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GUEST EDITORIAL |
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Year : 2020 | Volume
: 68
| Issue : 12 | Page : 2641-2642 |
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Refractive surgery: Where are we today?
Mahipal S Sachdev
Managing Editor, Indian Journal of Ophthalmology; President, All India Ophthalmological Society; Chairman, Centre for Sight, B-5/24, Safdarjung Enclave, New Delhi - 110029, India
Date of Web Publication | 23-Nov-2020 |
Correspondence Address: Mahipal S Sachdev Managing Editor, Indian Journal of Ophthalmology; President, All India Ophthalmological Society; Chairman, Centre for Sight, B-5/24, Safdarjung Enclave, New Delhi - 110029 India
Source of Support: None, Conflict of Interest: None | Check |
DOI: 10.4103/0301-4738.301284
How to cite this article: Sachdev MS. Refractive surgery: Where are we today?. Indian J Ophthalmol 2020;68:2641-2 |
The journey began in 1898 when L.J. Lans conceived the idea of corneal remodeling by creating multiple incisions in the stromal tissue. Thereafter, the field of refractive surgery has witnessed numerous advancements in technique and technology.
The techniques in refractive surgery have diversified, with enhanced indications in eyes deemed unsuitable for refractive correction in the past. Lens-based procedures including phakic intraocular lens (IOL) and multifocal IOLs, alone or in combination with corneal based procedures (bioptics) have extended the spectrum of refractive errors and ectatic disorders that can be treated safely and effectively.
The role of preoperative assessment and screening can never be underestimated, with greater importance lying in detecting patients who should be rejected, rather than selecting those who are safe. Advancements in the field of optical coherence tomography (OCT) has expanded its application in refractive surgery, wherein epithelial mapping could potentially provide the earliest signs of ectasia.[1] Combining corneal biomechanics with tomography adds the fourth dimension to preoperative assessment, detecting subtle subclinical ectasia.[2] Artificial intelligence and machine/deep learning are on the horizon wherein population-based data analysis and specifically designed algorithms enhance preoperative and postsurgical decision making.[3],[4],[5] Understanding and implementing wavefront aberrometry plays an important role in giving us the “supervision,” however, a shift from the current monochromatic to polychromatic aberrometry is imminent.
Over the past decade, a gradual shift from flap-based keratorefractive procedures to flap-free lenticule extraction has occurred. This novel technique provides superior biomechanical strength and lower postoperative dry eye vis-à-vis its earlier predecessors, with comparable, if not better, visual outcomes.[6],[7],[8],[9] Innovative procedures utilizing the extracted lenticule from Small Incision Lenticule Extraction (SMILE) have been described including customized stromal expansion for cross-linking thin corneas, stromal implants for keratoconus, and treatment of hyperopia and presbyopia.[10],[11],[12],[13],[14],[15] Potential advantages include a more physiological treatment wherein the properties of the lenticule are similar to the underlying stromal tissue. Decellularized lenticule further reduces the risk of rejection.[11] However, further studies establishing long-term safety and efficacy are warranted.
Treatment of presbyopia has additionally witnessed numerous advancements over the past decade including laser blended vision, corneal inlays, trifocal IOLs, and multifocal phakic IOLs.[16] The refractive surgical world stands in very exciting times where the pharmacological treatment of refractive errors is also being assessed. Developments have been made in “reversing” presbyopia using eye drops, wherein the crystalline lens can be made “younger” by making it more flexible. Pharmacological management to arrest the progression of myopia has been tried with controversial results.[17] Breakthrough advancements in the pharmacological field can change the history and future of refractive surgery forever.
With cataract surgery providing us exceptional and predictable visual outcomes, it is now considered under the spectrum of refractive surgery. Cataract surgery is reaching new frontiers with both surgeons and patients striving for excellence. The post-laser vision correction cataract patient is now routine and expects postoperative unaided emmetropia. The concept of refractive index shaping (RIS) has been introduced wherein the refractive power of the intraocular implant can be altered postoperatively utilizing a femtosecond (FS) laser.[18] The FS laser creates an increase in hydrophilicity and a decrease in refractive index in the treated area, as the laser builds a RIS within the lens. RIS has also been shown to create an area of multifocality in monofocal lenses. This concept is being extrapolated for keratorefractive surgery in the form of laser-induced refractive index change (LIRIC).[19] LIRIC uses an FS laser at lower energies, and at a wavelength of 405 nm, to alter the collagen fibril density of the cornea, thereby altering the refractive index. It can be used to treat myopia, hyperopia, astigmatism, and higher-order aberration profile.
The current generation of refractive surgeons experience the unfortunate burden of complications of the refractive procedures of yesteryears, in addition to their own. We must aim at a perfect refractive surgery model, wherein the future generations can seamlessly connect with our patients, as their own, with minimal complications.
In conclusion, the field of refractive surgery is perhaps one of the most exciting avenues in ophthalmology with rapid advancements in technology and the optimization of preexisting techniques.
References | | |
1. | Silverman RH, Urs R, Roychoudhury A, Archer TJ, Gobbe M, Reinstein DZ. Epithelial remodeling as basis for machine-based identification of keratoconus. Investig Ophthalmol Vis Sci 2014;55:1580-7. |
2. | Ambrosio R Jr, Lopes BT, Faria-Correia F, Salomao MQ, Buhren J, Roberts CJ, et al. Integration of Scheimpflug-based corneal tomography and biomechanical assessments for enhancing ectasia detection. J Refract Surg 2017;33:434-43. |
3. | Arbelaez MC, Versaci F, Vestri G, Barboni P, Savini G. Use of a support vector machine for keratoconus and subclinical keratoconus detection by topographic and tomographic data. Ophthalmology 2012;119:2231-8. |
4. | Smadja D, Touboul D, Cohen A, Doveh E, Santhiago MR, Mello GR, et al. Detection of subclinical keratoconus using an auto- mated decision tree classification. Am J Ophthalmol 2013;156:237-46 e231. |
5. | Yousefi S, Yousefi E, Takahashi H, Hayashi T, Tampo H, Inoda S, et al. Keratoconus severity identification using unsupervised machine learning. PLoS One 2018;13:e0205998. |
6. | Vestergaard AH, Grauslund J, Ivarsen AR, Hjortdal JO. Efficacy, safety, predictability, contrast sensitivity, and aberrations after femtosecond laser lenticule extraction. J Cataract Refract Surg 2014;40:403-11. |
7. | Sekundo W, Gertnere J, Bertelmann T, Solomatin I. One-year refractive results, contrast sensitivity, high-order aberrations and complications after myopic small-incision lenticule extraction (ReLEx SMILE). Graefes Arch Clin Exp Ophthalmol 2014;252:837-43. |
8. | Moshirfar M, McCaughey MV, Reinstein DZ, Shah R, Santiago Caban L, Fenzl CR. Small-incision lenticule extraction. J Cataract Refract Surg 2015;41:652-65. |
9. | Randleman JB, Dawson DG, Grossniklaus HE, McCarey BE, Edelhauser HF. Depth-dependent cohesive tensile strength in human donor corneas: Implications for refractive surgery. J Refract Surg 2008;24:S85-9. |
10. | Sachdev M, Gupta D, Sachdev G, Sachdev R. Tailored stromal expansion with a refractive lenticule for crosslinking the ultrathin cornea. J Cataract Refract Surg 2015;41:918-23. |
11. | Alio Del Barrio JL, El Zarif M, Azaar A, Makdissy N, Khalil C, Harb W, et al. Corneal stroma enhancement with decellularized stromal laminas with or without stem cell recellularization for advanced keratoconus. Am J Ophthalmol 2018;186:47-58. |
12. | Mastropasqua L, Nubile M, Salgari N, Mastropasqua R. Femtosecond laser-assisted stromal lenticule addition keratoplasty for the treatment of advanced keratoconus: A preliminary study. J Refract Surg 2018;34:36-44. |
13. | Li M, Li M, Sun L, Ni K, Zhou X. Predictive formula for refraction of autologous lenticule implantation for hyperopia correction. J Refract Surg 2017;33:827-33. |
14. | Pradhan KR, Reinstein DZ, Carp GI, Archer TJ, Gobbe M, Gurung R. Femtosecond laser-assisted keyhole endokeratophakia: Correction of hyperopia by implantation of an allogeneic lenticule obtained by SMILE from a myopic donor. J Refract Surg 2013;29:777-82. |
15. | Jacob S, Kumar DA, Agarwal A, Agarwal A, Aravind R, Saijimol AI. Preliminary evidence of successful near vision enhancement with a new technique: PrEsbyopic allogenic refractive lenticule (PEARL) corneal inlay using a SMILE lenticule. J Refract Surg 2017;33:224-9. |
16. | A study to evaluate the safety and efficacy of EV06 ophthalmic solution in improving vision in subjects with presbyopia. Available from: Clinicaltrials.gov.clinicaltrials.gov/ct2/show/NCT02516306?term=UNR844&draw=2&rank=2. [Last accessed on 2020 Aug 12]. |
17. | Sathyan S. The use of atropine in childhood myopia: Experience in Indian eyes. Kerala J Ophthalmol 2019;31:24-7. [Full text] |
18. | Bille JF, Sahler R, Zhou S, Aguilera R, Schanzlin DJ. Refractive index shaping of intraocular lenses using the 2 phase wrapping algorithm. Invest Ophthalmol Vis Sci 2011;52:4733. |
19. | Zheleznyak L, Butler SC, Cox IG, Huxlin KR, Ellis JD, Knox W, et al. First-in-human laser-induced refractive index change (LIRIC) treatment of the cornea. Invest Ophthalmol Vis Sci 2019;60:5079. |
Authors | | |
Prof. Mahipal S Sachdev, MD
Prof. Mahipal Singh Sachdev, an alumnus of and a former faculty at the Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, is an Ophthalmic entrepreneur with deep academic passion. He received specialty training in Cornea at the Georgetown University, USA. He is the current President of the All India Ophthalmological Society and is the founding Chairman and Medical Director of Centre for Sight, a nation-wide network of 43 specialty eye hospitals. Dr Sachdev was one of the youngest to chair the All India Ophthalmological Society Scientific Committee; he was also the Secretary and President of Delhi Ophthalmological Society, and Secretary and Chairman, Scientific Committee of the Intraocular Implant and Refractive Society of India. Dr. Sachdev was honored with Padmashri award by the Government of India in 2007 for his contributions to Ophthalmology. Dr Sachdev is the Managing Editor of the Indian Journal of Ophthalmology.
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