Recent advances in the diagnosis and treatment of ectatic corneal disease have mandated a more modern staging system. The new Belin ABCD keratoconus staging system incorporates anterior and posterior curvature centered on the thinnest point of the cornea, thinnest pachymetry values and distance visual acuity in grades from 0-4. By including posterior curvature and thickness measurements based on the thinnest point, as opposed to apical, the new staging system better reflects anatomical changes seen in keratoconus and other ectatic diseases.

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Purpose: The aim of this study was to compare the visual outcomes of two monofocal intraocular lenses (IOLs), with emphasis on the defocus curve. Methods: A total of 116 consecutive eyes with cataract, undergoing phacoemulsification with IOL implantation were included in the observational case series, and divided into two groups. 71 eyes were implanted with Tecnis Eyhance and 45 with Tecnis 1 monofocal IOL. Eyes with ocular comorbidities, previous ocular surgeries and corneal astigmatism >1 Diopters (D) were excluded from the study. Complete ophthalmic evaluation including uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected intermediate visual acuity (UIVA), corrected intermediate visual acuity (CIVA), uncorrected visual acuity (UNVA), corrected near visual acuity (CNVA) was noted and defocus levels ranging from -4.00 D to + 1.00 D were plotted postoperatively in both groups. Results: Uncorrected intermediate visual acuity (UIVA) and uncorrected near visual acuity (UNVA) was significantly better in Tecnis Eyhance group compared to Tecnis 1 monofocal. Both the IOLs have similar performance for distance vision but visual acuity at intermediate and near is significantly better with Tecnis Eyhance compared to Tecnis 1 piece IOL. Conclusion: Tecnis Eyhance IOL with its better defocus curve, not only provides good distance, but intermediate vision as well. With significantly better visual acuity across the range of near and intermediate vision, Tecnis Eyhance IOL can prove to be a viable and reasonable option for patients who are more dependent on intermediate vision in daily activities.

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Keratoconus (KC) is a progressive ectatic corneal disorder. There are multiple topographic devices and their varied indices used for diagnosis, detecting progression, and deciding management. It is important to understand the repeatablility, intra- test variabililty, and comparability amongst various topographic devices. The Scheimpflug camera-based devices, such as the Pentacam (Oculus, Wetzlar, Germany), Galilei (Ziemer, Biel, Switzerland), and Sirius (Costruzione Strumenti Oftalmici, Florence, Italy) are known to assist in the detection of early keratoconus and subclinical keratoconus. This article reviews the various Scheimpflug camera-based devices in depth, addressing their different indices, diagnostic accuracy, repeatability, and agreement and identifying the strongest parameter of each device. It will guide the practicing clinician by giving practical tips for decision making in the diagnosis and management of keratoconus.

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Detailed clinical assessment of corneal biomechanics has the potential to revolutionize the ophthalmic industry through enabling quicker and more proficient diagnosis of corneal disease, safer and more effective surgical treatments, and the provision of customized and optimized care. Despite these wide-ranging benefits, and an outstanding clinical need, the provision of technology capable of the assessment of corneal biomechanics in the clinic is still in its infancy. While laboratory-based technologies have progressed significantly over the past decade, there remain significant gaps in our knowledge regarding corneal biomechanics and how they relate to shape and function, and how they change in disease and after surgical intervention. Here, we discuss the importance, relevance, and challenges associated with the assessment of corneal biomechanics and review the techniques currently available and underdevelopment in both the laboratory and the clinic.

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The past two decades have witnessed an unprecedented evolution in the management of keratoconus that demands a holistic approach comprising of inhibiting the ectatic progression as well as visual rehabilitation. The advent of corneal cross-linking (CXL) in the late 1990s resulted in long-term stabilization of the ectatic cornea along with limited reduction in corneal steepening and regularization of corneal curvature. However, CXL as a standalone procedure does not suffice in rehabilitating the functional vision especially in patients who are unwilling or intolerant towards contact lenses. The concept of “CXL plus” was proposed which incorporates adjunctive use of refractive procedures with CXL in order to overcome the optical inefficiency due to corneal irregularity, decrease the irregular astigmatism, correct the residual refractive error and improve functional visual outcome in keratoconus. Several refractive procedures such as conductive keratoplasty (CK), photorefractive keratectomy (PRK), transepithelial phototherapeutic keratectomy (t-PTK), intrastromal corneal ring segments (ICRS) implantation, phakic intraocular lens (PIOL) implantation and multiple other techniques have been combined with CXL to optimize and enhance the CXL outcome. This review aimed to summarize the different protocols of CXL plus, provide guidelines for selection of the optimum CXL plus technique and aid in decision-making for the comprehensive management of cases with primary keratoconus in addition to discussing the future and scope for innovations in the existing treatment protocols.

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Contact lens-assisted corneal cross-linking (CACXL) was introduced by Jacob et al. in 2012 for treating thin keratoconic corneas using riboflavin soaked soft contact lens to artificially increase the functional corneal thickness. It is advantageous over other thin corneal cross-linking techniques as it works independent of swelling properties of the cornea, is an epi-off technique and does not require additional time, additional expensive equipments or special solutions. The only additional requirement as compared to all other techniques is a UV barrier-free soft contact lens (Soflens^TM, B&L) which is easily available and inexpensive. Advantages include simplicity, easy adaptability, early visual rehabilitation, good visual outcomes, safety, and efficacy. Progression rates are acceptable and the need for re-treatment has been low. CACXL can help regularize corneal shape and may be used in isolation or synergistically with Intracorneal ring segments (ICRS) or Corneal allogenic intrastromal ring segments (CAIRS). It gives about 70% stiffening as compared to standard Dresden protocol CXL in less ideal porcine eye studies. Murine eye models that closely mimic thin corneas and show greater cross-linking effect as compared to porcine eyes may be a better model for evaluation of CACXL, however further studies are needed. Care should be taken in selecting the right kind of contact lens. Proper technique should be followed, especially by confirming thinnest functional pachymetry to be above 400 microns intra-operatively before application of UV-A. The sub-contact lens riboflavin film should be avoided as also an excessively thick supra-contact lens riboflavin film and too many re-applications.

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One of the leading challenges in refractive surgery today is the presence of underlying subclinical early-stage keratoconus (KC), which can lead to iatrogenic post laser in situ keratomileusis ectasia. Timely detection of this condition could aid the refractive surgeons in better decision-making. This includes being able to defer refractive surgery in subclinical cases as well as providing treatment for the same in the form of appropriate corneal collagen crosslinking treatments. Corneal topography is considered the gold standard for the diagnosis of corneal ectatic disorders. However, there is a likelihood that topographers are overlooking certain subclinical cases. The corneal epithelium is known to remodel, which may mask underlying stromal irregularities. Imaging and analyzing corneal epithelium and stroma independently will undoubtedly open newer avenues to supplement our understanding of postrefractive surgery outcomes and KC. This review encapsulates the various Optical coherence tomography-based epithelial mapping devices particularly RTVue (Optovue, Fremont, USA) and MS-39 (Costruzione Strumenti Oftalmici, Florence, Italy) in terms of their utility in these conditions. It will help guide the clinician on how including an epithelial mapping in clinical practice can aid in diagnosis, management, and interpretation of outcomes both for refractive surgery as well as KC.

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Purpose: The aim of this study was to compare the visual outcome of participants undergoing toric intraocular lens (IOL) implantation after cataract extraction using manual marking versus digital marking for intraoperative guidance. Methods: Randomized controlled trial of participants with cataract and corneal astigmatism of 1.00 D-4.50 D. The eyes were grouped into manual marking (Group 1) and digital marking (Group 2). Preoperative Uncorrected distance visual acuity (UDVA), Corrected distance visual acuity (CDVA), and corneal astigmatism were determined. IOL power and axis of alignment were determined using Barrett toric calculator. Eyes were marked by bubble marker and Mendez ring in group 1 and by VERION (Alcon, Fort Worth, Texas) digital overlay in Group 2. Postoperatively, UDVA, CDVA, residual refractive cylinder and IOL misalignment were determined (iTrace system, Tracey technologies) at 1 week, 6 weeks, and 3 months. Results: A total of 61 eyes of 50 participants, 31 in Group 1 and 30 in Group 2, were studied. The mean postoperative cylindrical error was 0.50 ± 0.39 D in Group 1 and 0.29 ± 0.34 D in Group 2 (P = 0.03). 67.74% (n = 21) and 93.55% (n = 29) eyes achieved a residual astigmatism of ≤0.50 D and ≤1.00 D, respectively, in Group 1, whereas 83.33% (n = 25) and 100% (n = 30) eyes achieved a residual astigmatism of ≤0.50 D and ≤1.00 D, respectively, in Group 2 at 3 months postoperatively. Toric IOL misalignment was 4.71 ± 3.12° in Group 1 and 4.03 ± 2.99° in Group 2 (P = 0.39). Conclusion: Accurate manual marking and digital marking are equally effective guides for toric IOL alignment, intraoperatively.

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Advances in phacodynamics and intraocular lenses (IOLs) has given second life to clear lens extraction (CLE) or refractive lens exchange (RLE) in recent years for the treatment of patients with high degrees of myopia, hyperopia, and astigmatism who are unsuitable for laser surgery. Furthermore, presbyopia treatment with RLE supplemented with multifocal or accommodating IOLs gives the dual benefit of correcting refractive errors with eliminating the need for cataract surgery. RLE should be consistent and effective for a good refractive outcome along with safety during the surgical procedure and in the postoperative period. Therefore, proper patient selection and accurate preoperative protocols for IOL power calculations and selection are important along with an appropriate choice of surgical procedure. Dysfunctional lens index is a new objective tool that helps surgeon to aid in diagnosing, counseling, and educating patients with dysfunctional clear lens. In this article, we give a brief overview about the application of RLE for individuals with presbyopia and refractive errors like myopia, hyperopia, and astigmatism who are not suitable for laser correction.

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Phakic intraocular lenses (pIOLs) are a common solution for the surgical correction of high myopia and myopia in thin corneas. Global trends result in increasing rates of patients with high myopia which will result in increased rates of pIOL implantation. Three types of lenses can be distinguished: anterior chamber angle-supported, anterior chamber iris-fixated, and posterior chamber phakic IOLs. The efficacy of phakic intraocular lenses is generally very good, but pIOLs have undergone many changes over the years to improve the safety profile and decrease pIOL-related complications such as endothelial cell loss, corneal decompensation and cataract formation. This article describes the efficacy and safety profiles of the most recent pIOLs, as well as suggests gaps of knowledge that are deserve additional research to optimize the results of pIOLs.

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The procedure of small incision lenticule extraction (SMILE) was introduced in 2011, and since then there has been an increase in the number of cases undergoing this procedure worldwide. The surgery has a learning curve and may be associated with problems in the intraoperative and postoperative periods. The intraoperative problems during SMILE surgery include the loss of suction, the occurrence of altered or irregular opaque bubble layer and black spots, difficulty in lenticular dissection and extraction, cap perforation, incision-related problems, and decentered ablation. Most of the postoperative problems are similar as in other laser refractive procedures, but with decreased incidence. The identification of risk factors, clinical features, and management of complications of SMILE help to obtain optimum refractive outcomes.

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PresbyLASIK is one of the most commonly used modalities of surgical correction in presbyopes with no cataract. Unlike monovision procedures, both the eyes are adjusted for near and distance, providing a good stereopsis. This works by creating a corneal multifocality and increasing the depth of focus. Most techniques of presbyLASIK currently employ hybrid methods, i.e., a component of monovision added on to a multifocal corneal ablation. Choosing an appropriate proportion of these two components according to the patients' requirements and meticulous patient selection are key to obtaining desirable outcomes. Being corneal-based procedures, presbyLASIK has shown to be reversible. Thorough updated knowledge of the different presbyLASIK procedures, their principles and outcomes based on previous studies is required before a refractive surgeon plans to start providing presbyLASIK services. We performed a comprehensive search on PubMed with the keywords “Presbyopia surgery,” “PresbyLASIK” “PresbyMAX,” “Supracor,” and “Custom-Q.” In this review article, we have explained the principles of the various presbyLASIK procedures, appropriate patient selection and planning on the devices with examples, and summarized the previously published outcomes of these techniques.

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Simultaneous corneal cross-linking (CXL) has been proposed as an adjunct therapy to corneal refractive procedures to prevent future ectasia, especially when performed in borderline corneas. This review analyses the currently available literature (minimum follow-up 6 months) on corneal refractive surgery and simultaneous CXL (PRK Xtra, LASIK Xtra, and SMILE Xtra) to evaluate the overall results including the safety, efficacy, and potential complications associated with these procedures. A comprehensive literature search of various electronic databases (PubMed, PubMed Central, Cochrane database, and MEDLINE) was performed up to 20^th May 2020. Four relevant studies were found for PRK Xtra, 12 for LASIK Xtra, and 3 for SMILE Xtra. The total number of eyes included in this review was 1,512: 294 for PRK Xtra, 221 for PRK-only, 446 eyes for LASIK Xtra, 398 eyes for LASIK-only, 91 for SMILE Xtra and 62 for SMILE-only. Current literature suggests that refractive surgery and simultaneous CXL is generally safe and delivers comparable results in terms of visual and refractive outcomes than refractive surgery alone. However, there is no consensus on a standard cross-linking protocol, and complications such as diffuse lamellar keratitis, central toxic keratopathy, and corneal ectasia following Xtra procedures have been reported. It is therefore suggested that surgeons exercise caution in case-selection and counsel their patients regarding the potential risks and benefits with Xtra procedures. Also, further studies are required to standardize the UV-A irradiation protocols and to evaluate the long-term effect on safety, refractive predictability, and stability of these procedures.

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Laser refractive surgery (LRS) is one of the most demanding areas of ophthalmic surgery and high level of precision is required to meet outcome expectations of patients. Post-operative recovery is of vital importance. Keratitis occurring after LRS can delay visual recovery. Both surface ablations [Photorefractive keratectomy (PRK)] as well as flap procedures [Laser in-situ keratomileusis (LASIK)/Small incision lenticule extraction] are prone to this complication. Reported incidence of post-LRS infectious keratitis is between 0% and 1.5%. The rate of infections after PRK seems to be higher than that after LASIK. Staphylococci, streptococci, and mycobacteria are the common etiological organisms. About 50–60% of patients present within the first week of surgery. Of the non-infectious keratitis, diffuse lamellar keratitis (DLK) is the most common with reported rates between 0.4% and 4.38%. The incidence of DLK seems to be higher with femtosecond LASIK than with microkeratome LASIK. A lot of stress is laid on prevention of this complication through proper case selection, asepsis, and use of improved protocols. Once keratitis develops, the right approach can help resolve this condition quickly. In cases of suspected microbial keratitis, laboratory identification of the organism is important. Most lesions resolve with medical management alone. Interface irrigation, flap amputation, collagen cross-linking and therapeutic penetrating keratoplasty (TPK) are reserved for severe/non-resolving cases. About 50–75% of all infectious keratitis cases post LRS resolve with a final vision of 20/40 or greater. Improved awareness, early diagnosis, and appropriate intervention can help limit the damage to cornea and preserve vision.

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We report a case series of patients who developed post-laser-assisted in situ keratomileusis (LASIK) ectasia or had a progression of keractesia during pregnancy. We reviewed the medical records of 12 patients (20 eyes) who had reported deterioration of vision during their pregnancy and were diagnosed with keractesia. All 12 patients had experienced symptoms of deterioration of vision between 2 months to 1 year of onset of their pregnancies. A total of 17 eyes of 10 patients had developed post-refractive surgery keractesia. Sixteen of these had undergone LASIK and one had undergone femtosecond lenticule extraction (FLEX). Three eyes of two patients had an exacerbation of keratoconus during pregnancy while one patient had associated hypothyroidism. The results indicate that the hormonal changes that take place in pregnant women can affect the biomechanical stability of the cornea and may trigger the onset of keractesia.

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Purpose: To evaluate the relation of the tear film on the quality of vision comparing parameters in normal patients to those having dry eye disease. Methods: 50 normal and 50 eyes with dry eye disease (DED) were included in the study. Patients were screened for dry eye with Schirmer's test, tear break up time, ocular surface staining, and assessment of meibomian gland disease. Their quality of vision was assessed using the Optical quality analysis system (OQAS). The results of dry eye evaluation were correlated with the parameters on the OQAS especially the mean objective scatter index (OSI). Results: Patients with dry eye and unstable tear film were found to have a significantly worse quality of vision and optical scatter (P < 0.05). They were also noted to have fluctuation of vision between blinks. Conclusion: Tear film optics can have an important bearing on the quality of vision and quality of life. A detailed assessment preoperatively will help improve surgical outcomes and patient satisfaction.

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Purpose: To report age-related variations in corneal biomechanical parameters in healthy Indians. Methods: A retrospective study where healthy Indian individuals aged between 5 and 70 years having undergone corneal biomechanics assessment using Corvis ST between January 2017 and December 2018 and having best corrected visual acuity of 20/20 were enrolled. Subjects with central corneal thickness <500 microns, intra-ocular pressure (IOP) ≥ 22 mmHg, refractive error ≥ 6.00D, history of any systemic and ocular disease, previous ocular surgery, poor scans quality, and subjects with any missing data were also excluded. Corneal biomechanical parameters were noted and compared across different age groups. Results: Total of 3125 eyes had undergone the Corvis ST analysis. After applying exclusion criteria, 718 right eyes of 718 patients were included for the analysis and were further divided into different age groups as per each decade (sample size), such as 5-10 (37), 11-20 (113), 21-30 (396), 31-40 (116), 41-50 (39), 50 and above (17). All the subjects were matched for IOP and central corneal thickness (p > 0.05). A total of 19 out of 26 corneal biomechanical parameters were significantly different across age groups (p < 0.05). Vinciguerra screening parameters, such as deformation amplitude ratio max, biomechanically corrected IOP, and stiffness parameter A1 were significantly different across different age groups (p < 0.05). Conclusion: Corneal biomechanical parameters are affected by age as cornea becomes progressively stiffer. The information reported here would serve as a reference for future corneal biomechanical researches and would help in differentiating the abnormal eyes from normal healthy eyes.

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Purpose: The purpose of this study was to evaluate wound healing abilities and efficacy of topical Vitamin C, Vitamin E, and acetylcysteine for their possible clinical use. Methods: The study was conducted on 36 eyes of 18 single-breed rabbits, Oryctolagus cuniculus, of both sexes. A 7.5 mm calibrated vacuum corneal trephine was used to induce a defect of 100 micron depth in center of both the corneas. The right eye of rabbits was selected as the control eye and the left eye as the trial eye, which received eyedrops as Group 1–10% Vitamin C eyedrops, Group 2–3% acetylcysteine eye drops, and Group 3–1% Vitamin E eye drops. Control eyes received ringer lactate. Evaluation was done for fluorescein stain positivity, epithelial defect size, and corneal haze on Day 2, Day 7, and Day 14 post induction of the epithelial defect. Results: On day 14, three eyes of control group, all Vitamin C and acetylcysteine treated eyes, and four Vitamin E treated eyes were fluorescein stain negative. The mean defect area on day 14 was 0, 0, 0.13, and 1.86 mm² in Vitamin C, Vitamin E, acetylcysteine, and control eyes, respectively. Vitamin C and Vitamin E control corneal haze better than acetylcysteine in experimentally induced corneal wounds in rabbits. Conclusion: The three trial drugs with different mechanism of action showed similar effect on healing of the experimentally created corneal wounds in rabbits, with comparison showing statistical insignificance.

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Phototherapeutic keratectomy (PTK) involves treating anterior corneal lesions by superficial corneal ablation using an excimer laser (193 nm). Some of the commonly treated conditions include recurrent corneal erosions (RCE), corneal dystrophies, spheroidal degeneration, keratoconus, and corneal scars. We discuss various techniques of PTK including large area PTK, focal PTK, and multifocal PTK and alternatives to PTK. Masking agents like hyaluronate, methylcellulose, and dextran are recommended to help achieve a better outcome when ablating irregular corneal surfaces. Antifibrotic agents like mitomycin C reduce the chances of recurrence of the disease, apart from minimizing the postoperative scarring. Some of the complications include induced hyperopia and irregular astigmatism, haze, recurrence, and corneal thinning. However, earlier postoperative recovery, possibility of a repeat procedure, and ability to control the depth of ablation make PTK a promising, minimally invasive alternative to keratoplasty in cases with anterior corneal pathologies.

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Dry eye disease (DED) is a condition that is fast reaching epidemic proportions around the world. Dry eye post-refractive surgery is the leading cause of iatrogenically induced DED. The wide variety of presentations and the disparity between signs and symptoms in many patients make this a very challenging aspect of our clinical practice. There has been a paradigm shift in the way we approach and treat this condition. The International Dry eye workshop has added new knowledge and focus to our management of dry eye. A wide range of newer diagnostic modalities are available for the diagnosis of DED. Dry eye is one of the most common side effects of refractive surgery and can have a bearing the patient's perception of surgical outcomes as well. A thorough understanding of the possible underlying etiopathologies of this disease and the difference in etiopathogenesis of postrefractive dry eye is essential for optimal outcomes. It is important to approach each case in a unique fashion and customize the therapy to the patient presentation. This review article compiles all these aspects of management of dry eye in general, and postrefractive surgery dry eye in particular; from the ones commonly practiced in the clinic to the newer modalities of therapy with insights into the disease from a more practical point of view.

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Refractive surgery has evolved from being a therapeutic correction of high refractive errors to a cosmetic correction. The expectations associated with such a surgery are enormous and one has to anticipate all possible complications and side-effects that come with the procedure and prepare accordingly. The most common amongst these is post-refractive surgery dry eye of which Meibomian gland dysfunction is a commonly associated cause. We present an understanding of various diagnostic imaging modalities that can be used for evaluating meibomian glands which can also serve as a visual aid for patient understanding. We also describe various common conditions which can silently cause changes in the gland architecture and function which are to be considered and evaluated for.

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Purpose: The aim of this study was to analyze the long-term changes in visual parameters, that is, contrast sensitivity (CS) and higher-order aberrations (HOAs), and corneal topography in the patients undergoing upper eyelid blepharoplasty (UEB) for dermatochalasis. Methods: This was a prospective, single surgeon, intervention study including patients (≥40 years age) having severe dermatochalasis with a minimum post-UEB follow-up of 12 months. The preoperative readings of CS (using Pelli–Robson chart), HOAs (using WaveLight ALLEGRO analyzer), and corneal topography (using topographic modeling system-4, Tomey corporation) were noted and compared at 3, 6, and 12 postoperative months. Results: We studied 30 patients (60 eyes) who underwent bilateral UEB. The majority of patients were females (n = 21,70%), and the mean age of patients was 56.53 ± 9.06 years. The preoperative and postoperative values of LogMAR visual acuity, log CS value, corneal topography measurements (K1, K2, cylinder value, and the axis), optical aberrations (total HOAs; third-order––trefoil & coma; four-order––spherical aberrations and secondary astigmatism, and tetrafoil) were compared. At 12 months, the mean CS value, the majority of HOAs, and corneal topography (only cylinder values) showed a stable, statistically significant difference in the postoperative period. Conclusion: The UEB may produce long-term, visually-beneficial, optical, and corneal changes. The patients undergoing cataract surgery aiming for spectacle independence may gain additional visual benefits with UEB.

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Corneal refractive surgeries are one of the commonly performed procedures for correction of refractive errors. Tear film abnormality is the most common postoperative complication of corneal refractive surgeries. Consequently, these procedures represent a clinically significant cause of dry eye disease. The mechanisms which lead to dry eye disease include corneal sensory nerve dysfunction, ocular surface desiccation, glandular apoptosis and ocular surface inflammation. Although transient tear film abnormalities occur in almost all patients following surgery, patients with pre-existing dry eye symptoms or dry eye disease are at significant risk of developing more severe or long-term ocular surface disease. As such, careful patient selection and preoperative evaluation is essential to ensuring successful surgical outcomes. This is particularly important with LASIK which has the strongest association with dry eye disease. Appropriate surface lubrication and anti-inflammatory therapy remains the cornerstone treatment. Timely and effective management is important to facilitate visual rehabilitation and reduce the risk of secondary complications. In this review we describe the causes, pathophysiology, risk factors, manifestations, and management of tear film dysfunction and dry eye disease following corneal refractive surgery.

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A young lady presented with very high vault and fixed dilated pupil along with optic capture of the implantable collamer lens (ICL). After thorough evaluation and ruling out the ICL sizing error, the optic capture was relieved and the ICL was rotated into vertical position. Single-pass four throw pupilloplasty was performed for the fixed dilated pupil. Postoperatively the ICL vault and the pupil size decreased and patient was asymptomatic. This case highlights a successful outcome of rotation of a nontoric ICL to reduce the high vaulting and optic capture along with single-pass four throw pupilloplasty.

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Purpose: To determine the changes in central corneal thickness (CCT) during the menstrual cycle in Indian women. Methods: A prospective observational clinical study at a tertiary care center between December 2015 and December 2018. One hundred and twenty sixty women between 18 and 45 years were included. The CCT was measured using an ultrasound pachymeter at three specific timelines of the menstrual cycle: at the beginning (1^st to 3^rd day), during ovulation time (14^th to 16^th day), and at the end of the cycle (28^th to 33^rd day). Phases of the cycle were confirmed by the urine luteinizing hormone level. Results: The mean CCT of both eyes was 541.76 ± 4.21 μm, 559.21 ± 4.50 μm, and 544.52 ± 8.06 μm at the beginning, mid, and end of cycle, respectively. The mean CCT of the right eye was 541.68 ± 4.15 μm, 559.08 ± 4.50 μm, and 544.44 ± 8.06 μm and of the left eye was 541.84 ± 4.27 μm, 559.35 ± 4.50 μm, and 544.61 ± 8.06 μm at the beginning, mid, and end of cycle, respectively. Conclusion: The CCT value was significantly (P < 0.001) higher during ovulation compared to the beginning and end of the menstrual cycle. Our study recommends adding menstrual history in the workup of women undergoing refractive surgery as physiological variations in the CCT may result in unexpected surgical outcomes.

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Purpose: The aim of this study was to evaluate the safety, efficacy, and complications of V4c Toric implantable collamer Lens (TICL) implantation for myopic astigmatism in the south Indian population. Methods: In this retrospective observational case series, a total of 109 eyes of 67 patients who underwent V4c TICL implantation (ICL, V4C Staar Surgical, Nidau, Switzerland) between January 2012 and August 2019 were studied with a minimum follow-up period of 6 months (mean 24 months). The main outcome measures were objective and subjective refraction, uncorrected distance visual acuity, corrected distance visual acuity (CDVA), safety, predictability, adverse events, and postoperative complications. Results: At 6 months, mean manifest refractive spherical equivalent (SE) decreased from -10.90 ± 3.7D preoperatively to -0.02 ± 0.13D postoperatively (P < 0.001) and mean cylinder decreased from -2.3 ± 1.3 D preoperatively to -0.04 ± 0.2 D postoperatively (P < 0.001). Postoperatively, SE within ± 0.5 D and ± 1.0 D of attempted correction were achieved in 96.3 (105 eyes) and 100% (109 eyes), respectively. Manifest refractive cylinder within ± 0.5 D and ± 1.0 D of attempted correction were achieved in 97.2 (106 eyes) and 100% (109 eyes), respectively. Sixty-two percent (68 eyes) showed no change in CDVA postoperatively, and no eye had lost lines of CDVA. The safety index was 1.12, and the efficacy index was 1.10. Complications were seen in two eyes (1.8%) due to high postoperative vault requiring secondary surgical interventions. Conclusion: V4c TICL is a highly effective, safe, and predictable option in treating myopic astigmatism with excellent improvement in vision and spectacle independence.

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Over the past two decades, excimer laser-based refractive surgery procedures have been successfully established for their safety and satisfactory visual outcomes. Surface ablation procedures or photorefractive keratectomy (PRK) are practised commonly for the correction of refractive errors including myopia, astigmatism and hyperopia. Satisfactory visual outcomes are achieved in majority of cases, although a very small percentage have issues related to corneal haze, regression, and its associated visual disturbances. To ensure optimal outcomes and to minimize complications, certain keys to success have been designed on the basis of the current review of literature on surface ablation procedures.

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Over the last decade, refractive surgery has been revolutionized by advancements in ablation profiles, available for the treatment of both regular and irregular corneas. Advances in corneal imaging have helped highlight the presence of higher-order aberrations, the correction of which could result in a better quality of vision. Topographic measurements being static are more repeatable and pupil independent and therefore provide the ideal platform for correction of both lower and higher-order aberrations and could result in improved visual quality even in patients with seemingly regular corneas. The combination of topography-guided treatment with collagen cross-linking has further increased the scope of treating irregular corneas like keratoconus, post-laser in-situ keratomileusis ectasia, and pellucid marginal degeneration. This review delves into the current literature and guidelines available for the topographic treatment of regular and irregular corneas.

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Purpose: To calculate a modified percentage tissue altered (mPTA) in post laser-assisted in-situ keratomileusis (LASIK) eyes and to validate its role as an independent factor to evaluate ectasia in the Indian population. Methods: A total of 333 consecutive eyes with normal preoperative corneal topography by combined placido and scheimpflug imaging-based topography system (SIRIUS) who underwent LASIK using a microkeratome between 2011 and 2014 at a tertiary level teaching hospital in south India, were retrospectively analyzed. Preoperatively patient's refraction, flap thickness (FT), ablation depth (AD), residual stromal bed (RSB), and thinnest corneal thickness (TCT) were recorded. The formula used was mPTA = (FT + AD)/TCT. mPTA was grouped into <0.4 (low risk), 0.40 - 0.45 (moderate risk), and >0.45 (high risk). All patients were called for follow-up and underwent a topography to look for ectasia. Results: In total 60.1%, 29.1%, and 10.8% patients had mPTA of <0.4, 0.40 - 0.45 and >0.45, respectively. However, after a minimum follow-up of 2 years, none of the patients had any sign of ectasia. Conclusion: Careful selection of patients is mandatory before proceeding for LASIK. Factors like corneal thickness, RSB, degree of myopia, and AD are more important. The role of mPTA >0.4 as an independent risk factor for post LASIK ectasia is questionable in Indian eyes. Other factors or a modified formula suitable for Indian eyes needs to be investigated. A larger follow-up period is also required as ectasia has been known to develop even after 2 years.

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Purpose: Measurement, calculations, visual assessment, and refractive status after monofocal toric intraocular lens (IOL) implantation were the purpose of this study. Methods: This was a hospital-based interventional prospective study, where 40 eyes were included with astigmatism of more than 2D. They underwent biometric assessment using Lenstar. Toric IOL power calculation was done based on Barrett's Toric calculation method. Preoperative axis marking was done using both bubble marker and direct slit beam to avoid cyclotorsion in sleeping position. On table, axis marking was reassessed. Post phacoemulsification, monofocal Supra Phob Toric IOL was rotated till its marking matches corneal axis marking. Postoperative best-corrected visual acuity was measured at 1 and 3 months. Results: Mean of refractive astigmatism reduced from 3.55 ± 0.97 preoperatively to 0.81 ± 0.28 at 1 month and 0.79 ± 0.27 at 3 months postoperatively. In total, 92.5% had residual astigmatism less than 1D at 3 months postoperatively, while 7.5% eyes had residual astigmatism more than 1D. In total, 72.5% patients had IOL rotation of less than or equal to 5°, 20% patients had it between 6° and 10° and 7.5% eyes had more than 10° at day 7 postoperatively, which required IOL repositioning. Conclusion: Accurate measurement of parameters and proper calculation reduce the postoperative residual astigmatism after toric IOL.

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Purpose: The aim of this study was to discuss the possible risk factors predisposing to post photorefractive keratectomy (PRK) haze formation and develop and validate a risk scoring system, so that this could be applied to our clinical practice as an algorithmic approach. Methods: Study was divided into 2 arms, in the retrospective arm we looked at 238 eyes of patients undergoing PRK where certain presumed risk factors from literature and clinical experience were identified and statistical significance of association was studied in the development of corneal haze. The risk scoring system was applied to the 450 eyes in the prospective arm for validation. This was then used to formulate an algorithmic approach to manage post-PRK haze. Results: 22 out of 238 eyes in the retrospective arm developed haze where risk factors such as contact lens intolerance, altered tear film break up time, meibomian gland drop out and vitamin d levels were significantly associated with post-PRK haze (p < 0.05) and these factors were identified in the prospective arm. Treatment of these modifiable factors led to a significant reduction in post-PRK haze. Conclusion: Thus identifying and treating risk factors of haze in patients undergoing PRK could improve surgical outcomes and patient satisfaction.

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Purpose: The aim of this study was to compare the incidence of post laser in situ keratomileusis (LASIK) dry eye with and without intraoperative extended duration temporary punctal plug placement. Methods: This retrospective study included myopicastigmatic eyes without a preoperative diagnosis of dry eye disease that underwent LASIK surgery between January 2017, and March 2018. Patients who received punctal plugs during surgery in addition to usual postoperative care were compared to a control group who received usual postoperative care alone. Visual acuity, safety and efficacy indices, as well as predictability and presence of dry eye disease were assessed 3–6 months after surgery. Results: A total of 345 eyes of 345 patients were included, 172 eyes received punctal plugs and 173 did not. The mean age was 30.4 ± 10 years (range: 17–60 years) and 46.1% (N = 159) were female. Both groups were similar in terms of preoperative parameters, including age, gender, spherical equivalent, pachymetry or contact lens use. Patients treated with punctal plugs had significantly less postoperative dry eye complaints (N = 37 vs. 58, 21.5% vs. 34.1% respectively, P = 0.001). Patients treated with plugs that did develop dry eye disease did so later (51.2 ± 77.64 days' vs. 20.78 ± 26.9 days, P = 0.009). Postoperative visual acuities were similar between groups (P > 0.05) at all postoperative follow-up visits as were safety (0.95 ± 0.16 vs. 0.99 ± 0.09, P = 0.30) and efficacy (1.01 ± 0.13 vs. 1.00 ± 0.11, P = 0.52) indices. Conclusion: Preventative temporary punctal plug placement during LASIK appears to reduce dry eye disease in the short term, without affecting visual acuity outcomes.

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Photorefractive keratectomy (PRK) eye surgery is widely used for patients at risk for corneal ectasia to maintain an aspheric corneal shape. Wavefront-guided (WFG) ablation profile was designed to reduce pre-existing higher-order aberrations (HOA). We aimed to compare the corneal aberrations and visual outcomes between WFG and Wavefront Optimized (WFO) PRK in patients with myopia. Eight randomized clinical trials were included. We searched PubMed, Scopus, Web of Science and CENTRAL at March 2020, and updated the search in September 2020 using relevant keywords, The data were extracted and pooled as Mean Difference (MD) with a 95% Confidence Interval (CI), using Review Manager software (version 5.4). Pooled results showed no significance between Uncorrected Distance Visual Acuity (UDVA) and Corrected Distance Visual Acuity (CDVA) between both groups underwent WFG and WFO PPR after three months follow up (MD = -0.03; 95% CI: [-0.06, 0.00]; P = 0.07), (MD = -0.02; 95% CI: [-0.04, 0.01]; P = 0.22) respectively. Although, no significant difference between mean manifest cylinder after three and 12 months follow up, but the total MD for mean manifest cylinder difference was significantly lower with the WFG treatment method (MD = -0.12, (95% CI: [0.23:-0.01], P = 0.03). This shows a slight advantage of the WFG over the WFO method. The visual performance showed similarity and excellent refractive outcomes in both WFO and WFG PRK. No significant statistical differences between the two approaches. On further comparison, there was a slight advantage of the WFG over the WFO method.

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A 42-year-old female presented with pain, photophobia, and superficial corneal infiltrates in mid-periphery in the left eye, after 2 days of uneventful bilateral SMILE procedure. Inspite of the medical treatment with fortified antibiotics, the infection spread to the interface, close to visual axis reducing UDVA from 20/16 to 20/80. Immediate surgical intervention in the form of scraping of interface lesions with 26G needle, interface wash with antibiotics and photoactivated chromophore for keratitis (PACK-CXL) was performed. After 24 h of bacterial culture Staphylococcus aureus was yielded. Interface wash and PACK-CXL was repeated after 48 h by which infiltrates reduced and early scarring was observed by 10^th post-op day. Subsequent topical steroids helped in limiting scar formation and UDVA improved to 20/30 at the final visit. Combined approach of interface wash with antibiotics and PACK-CXL may be a safe and effective modality in treating early onset infectious keratitis following SMILE surgery.

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Purpose: To evaluate corneal biomechanical changes and their correlation with the percentage of tissue altered (PTA) in myopic femtosecond (FS)-flap LASIK. Methods: Prospective longitudinal observational study of 80 eyes of FS LASIK. Demographic details, LASIK parameters, preoperative and postoperative (day 1, month 1, 3, and 6), UCVA, BCVA, refraction, corneal topography, corneal hysteresis (CH), and a corneal resistance factor (CRF) were noted. Change in CH and CRF and its correlation with PTA were analyzed. Data were analyzed in three subgroups [subgroup 1: PTA 23 to <27%; subgroup 2: 27 to <33%; subgroup 3: 33 to <40%]. Results: FS LASIK for MRSE -3.5D ± 1.6D with mean PTA of 31.6 ± 4.4% (range 23.8–39.8%), showed statistically significant decrease in CH and CRF. Mean CH decreased from a preoperative value of 10.4 ± 1.9 to 8.1 ± 1.1; mean CRF from 10.5 ± 1.6 to 7.5 ± 1.3 at 6-months postoperative period, respectively. Mean preoperative CH decreased by 25%, 24%, 23%, and 21% and mean preoperative CRF decreased by 34%, 28%, 28%, and 28% at postoperative day 1, month 1, 3, and 6 follow-ups. Mean CH and CRF showed a significant negative correlation with PTA (CH: r = - 0.33 [P = <0.0001], CRF: r = -0.34 [P = <0.001]. Subgroup analysis noted greater decrease in CRF and CH in eyes with higher PTA (subgroup 3). Conclusion: Myopic FS LASIK causes a decrease in corneal biomechanics with a significant negative correlation with PTA indicating a greater decrease in corneal biomechanics with higher PTA.

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Purpose: The aim of this study was to evaluate visual quality after high-frequency transepithelial photorefractive keratectomy (t-PRK) by assessing the relationship between the operational parameters and the first-year postoperative corneal higher-order aberrations (HOAs). Methods: This was a retrospective study of low-to-moderate myopic eyes treated with t-PRK. The files of 46 low-to-moderate myopic patients (90 eyes; myopia up to −5D) were included in the study. Eyes having a cylindrical refractive error more than 2D and the patients not having completed a 1-year follow-up were excluded from the study. Factors including age, preoperative mean spherical equivalent (MSE), mean keratometry (Km), central corneal thickness (CCT), scotopic pupil, optical zone (OZ), transition zone (TZ), ablation zone (AZ), central ablation depth (CAD), and static cyclotorsion correction (SCC) were analyzed for association with the first-year postoperative corneal HOAs. Results: Corneal HOAs were found to be increased postoperatively with a 6-mm pupil (P < 0.05). The increased spherical aberration had a positive correlation with patient age, preoperative MSE, Km, TZ, and CAD, whereas it had a negative relationship with OZ and AZ (P < 0.05). The corneal coma had a significantly positive correlation with preoperative MSE and a significantly negative relationship with OZ (P < .05). Conclusion: Postoperatively induced corneal HOAs may affect patients' scotopic vision (night time driving, cinema) when the pupils get larger. The relationship between patient age, preoperative MSE, Km, CAD, TZ, OZ, AZ, and postoperative corneal HOAs underlines the need to consider the effects of these parameters on the final vision quality.

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Purpose: We aimed to compare transepithelial photorefractive keratectomy (TPRK) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for myopia treatment by analyzing corneal curvature, asphericity (Q-value), and corneal aberration. Methods: Corneal topography was measured before and 6 months after the TPRK or FS-LASIK surgery. We measured and compared corneal curvature (sagittal curvature in the 1- to 7-mm zones), change in keratometric measurements (Kmpost – Kmpre, ΔK), Q-values (from the vertex of the 6-, 7-, 8-, and 9-mm zones), higher-order aberration (HOA), vertical and horizontal trefoil (Z3^-3 and Z3³), vertical and horizontal coma (Z3^-1 and Z3¹), and spherical aberration (Z4⁰) between the two surgery groups. Results: The sagittal curvature Δ K in the 1-mm zone after TPRK was significantly higher than after FS-LASIK. The Δ K/ΔSE (ΔSE [spherical equivalent] = SEpre – SEpost) ratio in the 1- to 4-mm diameter zones was significantly higher after TPRK than after FS-LASIK. The preoperative Q-values of the 6- and 7-mm zones did not differ between the treatment groups, but postoperative values were significantly higher following FS-LASIK than following TPRK. HOA, Z4⁰, and Z3^-1 were all significantly higher after surgery in both groups. Postoperative Z3^-3 was significantly higher following TPRK but not following FS-LASIK. There were no postoperative differences in aberrations in either group; however, the change in HOA and Z3^-1 was significantly greater following FS-LASIK. Conclusion: TPRK changes the corneal curvature to a greater extent and the visual quality (Q-value, aberrations) to a lesser extent than FS-LASIK.

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Purpose: To estimate the time taken for topometric indices to stabilize in keratoconic corneas following cessation of habitual RGP contact lens wear. Methods: A total of 29 eyes of 20 patients, diagnosed with mild to severe keratoconus were included in this prospective observational study. All patients were experienced RGP contact lens wearers (either conventional RGP or Rose K2 lens) with each patient having used these lenses for at least a year. Corneal topography was performed immediately following discontinuation of habitual contact lens wear at baseline and each of four consecutive visits, 1-week apart. Results: An overall reduction in the keratometry and thickness values were noted on tomography immediately following cessation of contact lens wear and these indices increased significantly in the 1^st week (P < 0.001). Consecutive visits following the first visit did not show any significant change in the topometric parameters (P > 0.05). Subgroup analysis revealed a similar trend in eyes with “severe” keratoconus and in eyes fitted with the “three-point touch” philosophy. However, eyes with “mild-moderate” keratoconus and those fitted with “apical clearance” fitting philosophy showed marginal differences even within the 1-week period of lens cessation. Conclusion: Maximum changes in keratometry and pachymetry values following discontinuation of RGP lens wear stabilize within the 1^st week of cessation of rigid lens wear in a keratoconic cornea. These changes were more pronounced in patients with severe keratoconus and those with an apical bearing fit. This information would be useful for practitioners to assess the progression of keratoconus in RGP lens users before collagen cross-linking.

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Purpose: Assessment of repeatability of Orbscan III in measuring steep keratometry (sKm), flat keratometry (fKm), thinnest corneal thickness (TCT), anterior chamber depth (ACD), white-to-white diameter (WTW) and 3 mm and 5 mm zonal irregularity in healthy eyes. Methods: In this prospective observatioanl study 100 eyes of 50 participants underwent three consecutive scans on Orbscan III by a single examiner with a gap of 5 minutes between scans. Statistical analysis was performed to assess the repeatability of sKm, fKm, TCT, WTW, ACD and parameters of 3- and 5 mm irregularity. Within subject standard deviation (Sw), coefficient of variation (CoV) and test retest variability (TRT) was calculated for the commonly used parameters, were the main outcome measures. The repeatability of sKm, fKm, TCT, WTW, ACD, 3 mm and 5 mm zonal irregularity on Orbscan III. Results: Total of 50 patients (25 male and 25 female) who fulfilled inclusion and exclusion criteria were assessed. sKm, fKm, TCT and WTW were found to have a TRT of 0.31, 0.29. 21.5 and 0.27, respectively, and the ICC values were found to be over 0.9, denoting high repeatability. Repeat measurements of parameters of irregularity and ACD were found to be statistically similar, again denoting similarity between repeat measurements. Conclusion: Orbscan III provides repeatable measurements of Sim-k, anterior chamber depth, thinnest corneal thickness, 3 mm and 5 mm zonal irregularity and white-to-white diameter in healthy eyes.

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Purpose: The purpose of this study is to establish the safety of clear lens extraction (CLE) for the correction of high myopia in patients unfit for implantable contact lenses (ICLs) and laser in situ keratomileusis in the central Indian population. Methods: In this retrospective observational study performed at a tertiary care centre, medical records of the patients who had undergone CLE with implantation of intraocular lens (IOL) to treat high myopia were retrieved. Details of the demographic profile, surgical procedure, complications, power, and type of IOLs implanted were recorded. Results: The average postoperative follow-up period was 64.1 ± 4.2 months. The average postoperative spherical power was −1.4 ± 0.6 D, which was much lower than the preoperative spectacle power -15 ± 4.4 D. There was improvement in the postoperative visual acuity (0.4 ± 0.2 logMAR) from the preoperative distant uncorrected visual acuity (0.8 ± 0.2 logMAR). No significant change in intraocular pressure (IOP) was observed. The postoperative average anterior chamber depth (ACD) (2.66 ± 0.1 mm) was significantly deeper than the preoperative ACD (2.61 ± 0.1 mm) P = 0.00. Barrage laser was required for lattice degeneration in one patient before CLE and in two patients during follow-up. Two patients (8.7%) required Nd:YAG capsulotomy for posterior capsular opacification. None of the patients had corneal decompensation, retinal detachment, or endophthalmitis. Conclusion: CLE with implantation of IOL is the safe procedure for correcting high myopia in patients who are unfit for ICL. None of the patient had eye loss in the follow-up period of 5 years. The low incidence of complications can be attributable to the closed chamber lens removal and implantation of IOL and prophylactic retinal treatment.

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Phakic intraocular lenses (IOL) are a boon for patients who want spectacle independence but are unable to get refractive correction through laser platforms due to high refractive error or certain corneal contraindications. Phakic IOL's (PIOL) have their own set of complications and challenges, the most important being getting the sizing right. This paper attempts to solve the problem of accurate sizing of PIOL's. Parameters needed for calculating the ideal size of PIOL's have been studied in a step by step manner using all possible tools depending upon the availability and preference of the surgeon. The pros and cons of using a particular tool for measurements have been highlighted along with illustrative case examples to help surgeons who are starting PIOL implantation surgery.

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We are in the midst of a shift towards using novel polynomials to decompose wavefront aberrations in a more ophthalmologically relevant way. Zernike polynomials have useful mathematical properties but fail to provide clinically relevant wavefront interpretation and predictions. We compared the distribution of the eye's aberrations and demonstrate some clinical applications of this using case studies comparing the results produced by the Zernike decomposition and evaluating them against the lower degree/higher degree (LD/HD) polynomial decomposition basis which clearly dissociates the higher and lower aberrations. In addition, innovative applications validate the LD/HD polynomial basis. Absence of artificial reduction of some higher order aberrations coefficients lead to a more realistic analysis. Here we summarize how wavefront analysis has evolved and demonstrate some of its new clinical applications.

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Two preteen siblings with the anterior-stromal variant of granular corneal dystrophy type 1 underwent multiple phototherapeutic keratectomies (PTK) (due to recurrences of the dystrophy) with progressively increasing hyperopia after each procedure. The last procedure performed was an additional photorefractive keratectomy along with the PTK which led to a decrease in the hyperopia with better refractive outcomes. The addition of mitomycin C may have led to a delay in the recurrence of the dystrophy.

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We report the clinical history and histopathology of the longest known postoperative course of a myopic cornea lenticule implanted via epikeratoplasty that also had been subjected to excimer laser and mitomycin. Despite the mechanical and photochemical processes the allogenic cornea stroma had sustained, it is notable that it retained structural integrity and clarity. This report affirms the potential long-term clarity and resilience of allogenic stromal cornea and supports its use as a potential stabilizing option in cornea allogenic intrastromal ring segments for keratoconus and variations thereof for other cornea disorders.

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A 24-year-old female underwent small incision lenticule extraction (SMILE) for myopic astigmatism OU. In the left eye, cap-lenticular adhesion along with tearing of the cap occurred, resulting in a gaped incision and transverse striae involving the visual axis on the first post op day. Uncorrected distance visual acuity (UDVA) was 20/32. The case was managed with interface wash and stretching of the cap, in order to iron out the striae. Post intervention, the UDVA improved to 20/20, striae resolved, and interface remained clear through a follow-up of nine months, suggesting that cap striae in SMILE may be similarly managed as the flap striae in laser-assisted in situ keratomileusis (LASIK), resulting in satisfactory visual outcomes.

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A 27-year-old female patient came for a routine postoperative check-up, with a history of bilateral ReLEx small incision lenticule extraction (SMILE) surgery done 1.5 years back. On examination, epithelial ingrowth was noticed in the left eye at 8–9'o'clock position. Topography showed excess flattening in the area of ingrowth. Anterior Segment OCT showed hyper-reflectivity and was measured to be at a depth of 120 microns from the corneal surface. As the ingrowth appeared non-progressive, with no involvement of the pupillary axis and no visual complaints, no active intervention was done. Nonetheless, treatment options available include mechanical scraping and Nd:YAG laser procedure.

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Ocular trauma can range from trivial to significant, with varying implications on the visual acuity and prognosis. A 32-year-old woman presented with complaints of blurring of vision following blunt ocular trauma with a previous history of having undergone implantable phakic contact lens (IPCL V2.0) implantation 2 years back. The corrected distance visual acuity (CDVA) was 20/20 in the right eye and 20/30 in the left eye. Slit-lamp examination revealed a prolapse of inferonasal IPCL footplate into the anterior chamber with pupillary entrapment. No corneal endothelial touch was noted. Immediate repositioning of the IPCL was performed and the patient regained a CDVA of 20/20 in the left eye, postoperatively. Traumatic dislocation of IPCL is a rare occurrence, which can be successfully managed by prompt surgery, thus avoiding further complications like corneal endothelial decompensation.

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We present an interesting case of a 58-year-old woman who presented coincident keratoconus and Fuchs' endothelial dystrophy. During the 7months following initial presentation, a decline in visual acuity was associated with an apparent improvement in keratoconus, as characterized by corneal tomography parameters, while an increase in corneal pachymetry was also observed. The patient has been managed with left endothelial keratoplasty. This case poses the interesting question of how to classify coincident corneal disease, as traditional parameters for grading the severity of KC are altered by the presence of Fuchs' Endothelial Corneal Dystrophy and vice versa. In such cases, it is important to be aware of coincident disease to more accurately assess progression when considering treatment options and timing.

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Pellucid marginal corneal degeneration (PMCD) is a progressive corneal ectasia that ultimately results in high regular astigmatism and correction of this astigmatism is always challenging. However, when a PMCD patient develops a cataract, it provides a golden opportunity to treat this coexisting astigmatism with toric intraocular lens (IOL) implantation. Regular toric IOLs would correct astigmatism only up to 6 diopters in the IOL plane but higher astigmatism would require customization of such IOLs. Our case report describes the long term outcomes of customized toric IOL to tackle this high astigmatism during cataract surgery in PMCD cases.

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Purpose: Assessment of pupil diameter in various light conditions and the corresponding corneal spherical aberrations in a cohort of Indian eyes with bilateral senile cataracts and the possible use of this data in aberrometric customization of intraocular lenses (IOLs). Methods: In this prospective observational study done at a tertiary eye care centre in India, the selected patients were subjected to measurement of their pupil diameters in scotopic, mesopic, and photopic conditions as well as the corresponding corneal spherical aberrations, using the Sirius Topographer (Costruzione Strumenti Oftalmici, Florence, Italy). Shapiro–Wilk test, Independent t-test, ANOVA with Bonferroni correction on post-hoc testing were used for statistical analysis. Results: 104 eyes of 52 patients were enrolled for the study. The mean age was 53 ± 11.88 years. The mean scotopic, mesopic, and photopic pupil sizes were 4.37 mm (4.11–4.63 mm), 3.92 mm (3.71 mm–4.15 mm), and 3.37 mm (3.18–3.67 mm), respectively. There was a statistically significant difference (P = <0.001) in the mean corneal spherical aberration measured at the 6 mm zone (0.23 ± 0.02 microns) and at the 4 mm zone (0.06 ± 0.01 microns). Conclusion: The mean corneal spherical aberration corresponding to the average mesopic pupil size of our patient population was substantially lower than that of the scotopic pupil size and also less than the amount corrected by most of the negative aspheric IOLs. This perhaps indicates the need for customising IOLs based on the spherical aberrations of cornea at the zone corresponding to the mesopic pupil diameter for optimal residual total postoperative spherical aberrations.

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Purpose: The aim of this study was to compute the sensitivity, specificity and inter-reader variability of ultra-widefield retinal imaging (Optomap 200Tx) for screening retinal lesions before myopic refractive surgery. Methods: Two hundred and eight eyes of 109 consecutive refractive surgery candidates were included in this study. All subjects underwent Optomap 200Tx, mydriatic slit-lamp lens examination and dilated retinal examination with scleral indentation by a retinal specialist. Retinal findings by indirect dilated examination by retinal specialist was considered as the gold-standard. Sensitivity analyses for the readers were calculated between the Optomap images and the gold-standard retinal examination. Results: Seventy-three of the 208 eyes (35.1%) had peripheral retinal lesions diagnosed by the retinal specialist on dilated fundus examination. Peripheral lesions were seen on the Optomap images in 111 (53.4%) eyes. Compared to the dilated retinal examination, the detection rate with the Optomap 200Tx was 78.1% and specificity rate was 60%. The accuracy rate between the 3 readers ranged from 72% to 87%. The highest accuracy was noted with the reader post 1 year of retinal training (86.54%). Conclusion: The Optomap 200Tx showed a high sensitivity and moderate specificity for identifying peripheral retinal lesions in eyes undergoing refractive surgery. The Optomap examination is a convenient, fast and feasible method for detecting the pathological fundus changes in myopic eyes. The reliability of the examination improves when the images are interpreted by a reader with prior retinal training.

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Purpose: Sterile infiltrates following laser refractive surgery is an uncommon complication. This study was undertaken to analyze the visual outcomes of sterile infiltrates following photorefractive keratectomy (PRK). Methods: This retrospective study included 14 eyes that developed sterile infiltrates following PRK out of a total of 6280 eyes that underwent PRK between 2014 and 2017. Medical records of these patients, including patient demographics, characteristics of the infiltrate, presenting visual acuity, and treatment outcomes were recorded and analyzed. Results: The incidence of sterile corneal infiltrates post-PRK in our study was 0.22% (14/6280). The mean age of the patients was 27.42 ± 4.87 years. The uncorrected visual acuity (UCVA) at presentation was 0.49 ± 0.13 log MAR units. The mean size of the infiltrate was 3.22 ± 2.85 mm². All cases were successfully managed medically with topical steroids. The mean UCVA and best-corrected visual acuity (BCVA) at the last follow-up visit were 0.08 ± 0.08 and 0.05 ± 0.07 log MAR units, respectively. The mean time taken for resolution of the infiltrate was 8.91 ± 4.57 days. Conclusion: Sterile infiltrates following PRK can be effectively treated with aggressive topical steroids. The outcome is generally favorable and does not require surgical intervention if treatment is instituted early.

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Purpose: To evaluate the long-term contrast sensitivity (CS) after laser in-situ keratomileusis (LASIK) for myopia. Methods: This retrospective, single-center, cohort study involved 190 eyes of 95 patients who underwent bilateral LASIK between January 2001 and October 2007. This study includes patients who underwent CS and higher-order aberration (HOA) measurements in a five-year postoperative period. For all enrolled patients, visual acuity, refractive error (RE) in diopters (D), CS at 3-, 6-, 12-, and 18-cycles per degree (cpd), and HOA in a 4 mm area of the dilated pupil were measured before surgery and 6 months, 1 year, and 5 years after it. Results: The mean RE measured before the surgery and after 6 months, 1 year, and 5 years after was -6.08 ± 2.50D, −0.26 ± 0.65D, −0.28 ± 0.65D, and −0.48 ± 0.80D, respectively. There were no clinically significant changes between preoperative results and the measures taken 6 months, 1 year, and 5 years after surgery. The slight increase in HOA had little effect on CS over the mid to long-term postoperative period. Conclusion: Our findings show that CS does not clinically change post LASIK. Although we were unable to identify the specific mechanism, we theorize that after LASIK there is a possibility for the compensation of HOA.

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Purpose: The aim of this study was to compare the predictability and accuracy of the American Society of Cataract and Refractive Surgery (ASCRS) online calculator with the Haigis-L formula for intraocular lens (IOL) power calculation in post myopic laser-assisted in-situ keratomileuses (LASIK) eyes undergoing cataract surgery and also to analyze the postoperative refractive outcome among the ASCRS average, maximum and minimum values. Methods: A retrospective study was conducted on post myopic LASIK eyes which underwent cataract surgery between June 2017 and December 2019. IOL power was calculated using both Haigis-L & ASCRS methods. Implanted IOL power was based on the ASCRS method. The expected postoperative refraction for IOL power based on the Haigis-L formula was calculated and compared with the Spherical Equivalent (SE) obtained from the patient's actual refraction. Prediction error (PE) & Mean Absolute Error (MAE) was calculated. Intragroup analysis of ASCRS values was done. Results: Among the 41 eyes analyzed, pre-operative and post-operative mean best-corrected visual acuity was 0.58 ± 0.21 and 0.15 ± 0.26 logMAR, respectively. In the ASCRS method, 36 (87.8%) and 40 (97.6%) eyes had PE within ± 0.5D and ± 1.0 D, respectively, whereas, in the Haigis-L method, 29 (70.7%) eyes, and 38 (92.7%) eyes had PE within ± 0.5D and ± 1.0 D, respectively. Among the ASCRS subgroups, ASCRS average, maximum and minimum values had 83%, 80.6%, and 48.8% eyes with SE within ± 0.5D, respectively. Conclusion: ASCRS method can be considered as an equally efficient method of IOL power calculation as the Haigis-L method in eyes which have undergone post myopic LASIK refractive surgery. ASCRS maximum & average values gave better emmetropic results.

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Refractive surgeries are one of most commonly performed surgeries for correcting visual impairment due to refractive errors. With the increase in demand for refractive surgeries, there is an enormous strain on the operating surgeon for delivering ideal outcomes i.e 20/20 visual acuity. Regression, under-correction and ectasia are the most dreaded complications post-refractive correction, for the surgeon as well as the patient. They have significant effects on the quantity of the vision and most importantly on the quality of life of the patient. With the advent of digital era and jobs requiring the eyes being glued to the screen for hours there has been a surge in the patients presenting with complaints of asthenopia, glare, halos, and difficulty in focusing; pointing towards diagnosis of non-strabismic binocular vision anomalies (NSBVA). NSBVA in a postrefractive surgery patient may masquerade as regression or under-correction. However, timely diagnosis of NSBVA in such patients would prevent the greater harm caused by wrongful re-correction. Home- and office-based vision therapy results in improvement in visual acuity in a large majority of these patients. This preferred practice pattern intends to guide the refractive surgeons to diagnose and treat the postrefractive surgery NSBVA following a case-based and algorithmic approach. It also emphasizes the inclusion of the binocular vision assessment as a part of the pre-operative workup for patients undergoing refractive procedures.

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Over the past decade, small incision lenticule extraction (SMILE) has revolutionized the field of keratorefractive surgery. With the promise of superior corneal biomechanics and reduced postoperative dry eye, SMILE afforded a distinct advantage over flap-based procedures. Our evolving understanding of the surgical technique and management of its unique complications has further enhanced the outcomes. This review will highlight specific pearls on various preoperative and intraoperative principles allowing optimization of outcomes with SMILE.

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Pigment dispersion syndrome predominantly affects young myopes. It is not uncommon for such patients to seek refractive surgery. It may also be encountered after an uneventful refractive surgery. We report a case of a young myopic male who presented with bilateral pigment dispersion syndrome 9 months after an uneventful photorefractive keratectomy. A meticulous ocular examination is the cornerstone of a successful refractive surgery. Through this report, we highlight the need for gonioscopy to be included as a routine examination in screening for refractive surgery.

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Transepithelial photorefractive keratectomy (tPRK) promotes faster re-epithelialization which in turn can reduce the risk of infectious keratitis in the postoperative period. We present a case of a 22-year-old man with infectious keratitis in his left eye 8 days after an uneventful bilateral tPRK. A 2 mm × 5 mm anterior stromal area of corneal infiltration with a same sized overlying epithelial defect was noted at the time of presentation. His uncorrected distance visual acuity was 20/63 in his left eye. Corneal scrapings showed Bordetella bronchiseptica. The infection responded to intensive treatment with topical levofloxacin 0.5% eye drops. The final visual acuity was 20/20 in the left eye.

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A 28-year-old male underwent microkeratome assisted Laser-assisted in situ keratomileusis (LASIK) for, myopia. On postoperative day 1, patient had a large epithelial defect in OD. The corneal epithelial defect healed within 72 hours, but sub-optimal vision persisted. The patient was referred for further management to us. On evaluation, patient had non-healing of flap margin at 5 o'clock. Fluoroscein stain revealed no corneal epithelial defect, but a large pool of dye beneath the LASIK flap. A clinical diagnosis of non-adherence of LASIK flap was considered. Application of bandage contact lens was done. LASIK flap completely healed in 1 week. Possible etiologies are discussed and literature is reviewed.

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Recurrence of myopia after myopic LASIK reduces the outcome of the procedure. Important causes include post-LASIK ectasia, regression of myopia, accommodative strain, and lens or axial length changes. Herein, we present a case of myopia recurring after LASIK and try to arrive at the possible diagnosis among these, as the treatment differs for each. The detailed evaluation showed that our patient had regression of myopia after LASIK. Of the multiple causes for recurrence of refractive error after myopic laser vision correction, it is important to identify the relevant reason as the treatment and prognosis for each of these is different.

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A 23-year-old male presented to us wanting spectacle removal for cosmetic purposes. He underwent bilateral wavefront optimized (WFO) laser-assisted in situ keratomileusis (LASIK) on the Alcon Wavelight ^® EX-500 excimer laser with an incorrectly treated astigmatism axis for left eye due to a manual data entry error in the laser. WFO LASIK treats the sphere and cylinder only. LASIK enhancement with topographic-guided ablation resulted in the elimination of all refractive errors and gave excellent results. Wavelight ^® topographic-guided treatment can perform two separate layers of correction in the same ablation: The first is to treat the corneal irregularities for the higher order aberration (HOA) removal, the second one meant to treat the sphere and cylinder if indicated.

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A 25-year-old male patient presented with chief complaints of itching in both eyes (OU) for the past one month. Detailed ophthalmic examination showed best-corrected visual acuity of 6/6 OU. On slit-lamp examination of the left eye, Vogt's striae were documented and rest of the anterior segment was normal OU. Pentacam-HR and ASOCT confirmed the diagnosis of keratoconus. The patient was started on Trehalose containing preparation for both eyes. On follow-up visit at 8 months, progression was documented on Pentacam-HR. MS-39 showed epithelial remodeling, but no stromal or posterior elevation, indicative of a pseudo-progression. Corneal epithelial remodeling post topical trehalose containing eye drops application has been very sparsely reported in literature. It is an important differential to consider when faced with a situation of a likely progression of keratoconus, especially to differentiate true from pseudo-progression.

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Purpose: The aim of this study was to measure blur thresholds before and after refractive surgery. Methods: In this prospective cohort study conducted in a tertiary eye hospital in South India. Blur thresholds were measured for 30 young adult myopic patients 1 month prior to and after refractive surgery. Patients were asked to report three stages of blur, namely Detectable Blur (DB), Bothersome Blur (BB), and Non-resolvable Blur (NB). Blur was created by adding plus lenses (in steps of 0.12D) over their optimal subjective refraction. The blur judgments were made both monocularly and binocularly when looking through a 3 mm artificial pupil at one line above the best-corrected visual acuity. Results: A total of 30 participants were included in this study (mean age = 25.5 ± 3.8 (20–36) years; 77% female). The mean binocular preoperative blur of this group was: DB = 0.39 ± 0.26D, BB = 0.74 ± 0.28D and NB = 1.04 ± 0.42D. The corresponding mean binocular blur one-month post-operatively was DB = 0.46 ± 0.28D, BB = 0.83 ± 0.35D, and NB = 1.21 ± 0.44D. Although there was a marginal increase in the blur thresholds postoperatively, the difference was not statistically significant (DB: P = 0.320; BB: P = 0.229; NB: P = 0.054). Conclusion: All three blur thresholds showed an insignificant minimal increase at 1 month post-operatively suggesting that patients adapt to the induced blur following refractive surgery. A longer follow up would reveal how the adaptation to blur would change with time.

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Purpose: The aim of this study was to analyze the effect of timolol maleate (0.5%) eye drops in the treatment of myopic regression after laser-assisted in-situ keratomileusis (LASIK). Methods: The study was conducted at a tertiary care eye hospital in north India between April 2017 & March 2018 as a prospective interventional study. Patients who underwent uneventful myopic LASIK with hansatome mechanical keratome and presented with regression were included in the study. Baseline demographic characteristics, time to presentation with regression best-corrected visual acuity (BCVA), refraction, intraocular pressure, central corneal thickness and keratometry were recorded at baseline and at each follow-up visit. The enrolled patients were prescribed timolol maleate (0.5%) eyedrops twice daily. They were followed up every month till 3 months on timolol maleate (0.5%) eyedrops and at 6 months post stopping the treatment. Results: Twenty-nine eyes of 15 patients were enrolled in the study. Mean pre LASIK spherical equivalent (SE) was – 7.48 ± 2.9 Diopters (Range-3.125 to –11.75 Diopters) and mean regression spherical equivalent was –1.02 ± 1.1 Diopters. There was a decrease in mean SE from presentation (intervention start point) up to 6 months follow-up (–1.34 ± 0.89 to –0.30 ± 0.29 Diopters). While posterior corneal curvature (K1 and K2 Back) changed significantly over treatment period (P = 0.0029, P = 0.0024 respectively), changes in anterior corneal curvature (K1 and K2 Front) were not significant (P = 0.05, P = 0.06 respectively). Central corneal thickness (CCT) and intraocular pressure (IOP) did not change significantly over treatment course. Conclusion: Timolol maleate (0.5%) eyedrop is an effective modality for the treatment of refractive regression post LASIK circumventing the need for laser re-treatment in such patients. The most probable mechanism is reversal of the anterior bowing of the cornea in response to intraocular pressure changes.

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Purpose: The aim of this work was to study the change in contrast sensitivity (CS) in relation to depth of stromal ablation after wavefront-optimized (WFO) myopic laser in situ keratomileusis (LASIK). Methods: This was as prospective, longitudinal, comparative study. The study participants were divided into two groups: Group 1 ≤50 μ ablation depth; 60 eyes and group 2 >50 μ ablation depth; 60 eyes. All underwent WFO LASIK. Uncorrected and corrected distance visual acuity (UDVA and CDVA) and CS were measured preoperatively and postoperatively at 1 week, 2 weeks, and 2 and 6 months. Two-way repeated-measures analysis of variance (ANOVA), Unpaired t test and one-way repeated measures ANOVA were used to test differences across time periods within each treatment group. A value of P < 0.05 was considered as statistically significant. Results: The mean ablation depths in groups 1 and 2 were 39.30 μ ± 7.22 μ and 69.90 μ ± 12.09 μ, respectively; the maximum depth was 94.62 μ. In group 1, the preoperative mean CS was 1.91 ± 0.07, which improved postoperatively at 1 week (1.93 ± 0.06) and remained stable in subsequent follow-ups (1.94 ± 0.05). In group 2, the mean CS preoperatively was 1.87 ± 0.12, which postoperatively at 1 week and 6 months were 1.93 ± 0.07 and 1.94 ± 0.03, respectively (P < 0.05). Between the groups, preoperative CS was significantly different (P = 0.04), but the change in CS post-LASIK was insignificant (P > 0.05). Conclusion: There was a significant improvement in CS after WFO myopic LASIK in all patients irrespective of ablation depth (up to 94.62 μ).

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The need and demand for surgical correction of refractive errors, particularly myopia, has been increasing. Degenerations involving the peripheral retina are common in myopes and can result in a rhegmatogenous retinal detachment. There are no clear guidelines for retinal screening and management of asymptomatic retinal degenerations prior to refractive surgery or for follow-up of these patients. This article aims to provide a set of guidelines for the management of retinal degenerations in eyes undergoing refractive surgeries.

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Ablation-related complications following the refractive procedures are a major challenge for a refractive surgeon, considering the elective nature of the procedure. The use of topography-guided customized ablation has revolutionized the management of irregular corneas postrefractive surgery. This preferred practice highlights various hurdles encountered while managing cases of decentered ablation, small ablation zones, and planning a cataract surgery in patients with irregular corneas. It will give insight to the refractive surgeon on the planning of corneal regularization on various modern-day refractive platforms available, such as the WaveLight^® EX-500 (Alcon Laboratories, Inc., Fort Worth, TX, USA), Schwind Amaris 1050 (Peramis; SCHWIND eye-tech-solutions, Kleinostheim, Germany), and Technolas Teneo 317 model 2 excimer laser (Bausch & Lomb, Rochester, NY, USA). The algorithmic approach outlined will enable the refractive surgeon to choose between the wavefront optomized and the topography-guided ablations.

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