|Year : 2009 | Volume
| Issue : 2 | Page : 165-169
Phakic intraocular lenses
Rajesh Sinha, Chandrashekhar Kumar, Jeewan S Titiyal
492, R. P. Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
|Date of Web Publication||17-Feb-2009|
492, R. P. Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, Ansari Nagar, New Delhi
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Sinha R, Kumar C, Titiyal JS. Phakic intraocular lenses. Indian J Ophthalmol 2009;57:165-9
Phakic intraocular lenses are fast becoming an important tool for the correction of ametropia. They are of various types and designs and can be used in various forms of refractive errors. We performed a review of some of the important articles published in indexed journals related to phakic intraocular lens.
| Indications and outcome|| |
Baikoff et al . ( J Refract Surg.1998;14(3):282-93 ) assessed the safety and efficacy of a second generation, anterior chamber (AC) phakic intraocular lens (PIOL) (Baikoff Model ZB5M) in patients of high myopia. One hundred and twenty one patients (134 eyes) with myopia of -7.00 to -18.80 diopters (D) were implanted with the ZB5M lens and followed for 18-52 months. They showed that implantation of AC PIOL produced a stable refractive outcome over three years, accompanied by marked improvement in uncorrected visual acuity (UCVA) and minimal, nonprogressive damage to the corneal endothelium.
Perez-Santonja et al . ( J Cataract Refract Surg.2000;26(9):1288-302 ) evaluated the effectiveness, predictability, and safety of a fourth-generation angle-supported AC PIOL in patients of severe myopia and found good results.
Maloney et al . ( Ophthalmology 2002;109(9):1631-41 ) evaluated the safety and efficacy of Artisan iris-supported PIOL in 155 eyes of 155 patients with myopia from -5.5 to -22.5 D. Patients were followed up for six months. Short-term results suggested that the Artisan lens is an accurate and safe method for the correction of high myopia.
Benedetti et al . ( J Refract Surg.2005;21(2):116-26 ) evaluated the safety and efficacy of iris claw PIOL (Artisan) in 93 eyes with high myopia. They confirmed that Artisan PIOLs are safe and effective for the correction of high myopia, with a stable refractive outcome but with a higher than normal rate of endothelial cell loss (ECL) during two-year follow-up.
Coullet et al . ( Am J Ophthalmol.2006;142(6):909-16 ) compared refractive performance of Artisan PIOL and its foldable version, Artiflex, for the correction of moderately high myopia. They found that to correct moderately high myopia, the Artiflex lens provides a faster visual recovery and a better UCVA than does the Artisan lens.
Gierek-Ciaciura et al . ( Graefes Arch Clin Exp Ophthalmol.2007;245(1):1-7 ) evaluated the efficacy, predictability, and safety of implanting two models of AC PIOLs for high myopia; ICARE myopia lens (angle supported lens) (20 eyes) and Verisyse iris fixated IOL (20 eyes). They showed that implantation of both AC PIOLs resulted in a stable and predictable refractive outcome.
Shen et al . (Zhonghua Yan Ke Za Zhi.2007;43(11):1000-4 ) evaluated posterior chamber (PC) PIOLs in 216 eyes of 113 patients of extreme myopia. The best corrected visual acuity (BCVA) improved by one or more lines in 168 eyes (77.8%) at one year after surgery. They concluded that PC PIOL is an effective, safe, and reliable method for the correction of extreme myopia.
| Hyperopia|| |
Pesando et al . ( J Cataract Refract Surg 2007;33(9):1579-84 ) evaluated collamer implantable contact lens (ICL) in 49 hyperopic eyes of 34 patients. Preoperatively, the spherical equivalent (SE) was between +2.75 D and +11.75 D and astigmatism was between +0.50 D and +1.00 D. The mean postoperative SE of the manifest refraction was +0.07 ± 0.54 D; refraction stabilized quickly and remained stable throughout the follow-up period. At 10 years, the safety index was 111 and the efficacy index 96.8. The results confirmed the long-term safety, efficacy, accuracy, and predictability of ICL for hyperopia.
Leccisotti A ( J Cataract Refract Surg.2005;31(8):1598-602 ) evaluated the efficacy and safety of angle-supported PIOLs (Morcher) in 42 hyperopic eyes of 22 patients implanted through a 5.5 x 3.0 mm sclerocorneal tunnel along the steepest meridian. The mean preoperative defocus equivalent (DEQ) was 7.30 ± 1.89 D. The mean SE was 6.61 ± 1.47 D, and the mean refractive astigmatism was 1.51 ± 1.33 D. Postoperative mean SE was 0.38 ± 0.52 D; mean DEQ was 0.93 ± 0.98 D; mean astigmatism was 0.95 ± 1.17 D; and mean surgically induced astigmatism (SIA) (vector analysis) was 0.67 ± 0.58 D. They reported that high hyperopia was corrected safely and predictably by an angle-supported IOL.
Munoz et al . ( J Cataract Refract Surg.2005;31(2):308-17 ) performed Artisan PIOL implantation followed by laser in situ keratomileusis (LASIK) for the correction of high hyperopia. Thirty nine eyes with a mean preoperative SE of 7.39 ± 1.30 D and a cylinder between 0 and -4.25 D were studied. The Artisan iris-fixated PIOL (Ophtec) for hyperopia was implanted, and LASIK was performed 6-8 months later for residual error. The minimum follow-up was 12 months. The combination of Artisan PIOL implantation and LASIK was safe, predictable, and effectively reduced high hyperopia. A loss of one line of BCVA may be expected in about one-third of eyes implanted with this IOL.
| High astigmatism|| |
Dick et al . ( Ophthalmology 2003;110(1):150-62 ) evaluated Artisan toric phakic intraocular lenses (TPIOLs) for the correction of myopia or hyperopia with astigmatism in 70 eyes of 53 patients. The preoperative SE was between +6.50 D and -21.25 D and astigmatism was between 1.50 D and 7.25 D. A six-month clinical trial demonstrated that implantation of the Artisan TPIOL was safe, predictable, and could effectively reduce or eliminate high ametropia and astigmatism with one procedure. The refractive effect was stable at six months after surgery.
Guell et al . ( Am J Ophthalmol 2003;136(3):442-7 ) evaluated Artisan TPIOL for the correction of astigmatism higher than 2 D in 27 eyes of 16 patients with a mean preoperative SE of -11.78 ± 6.24 D and a mean preoperative astigmatism of -3.43 ± 0.81 D. Twelve months after the implantation of the lens, 62.90% of the eyes were within ± 0.50 D of emmetropia and 96.20% within ±1.0 D. Seventy percent of the eyes gained one or more lines of Snellen acuity over their preoperative BCVA, and 11.11% lost one Snellen line. Mean of the parallel and orthogonal components of cylinder correction were 1.97 D and 0.10 D, respectively, of the intended cylinder change. The mean of axis alignment error was 10.53º. They found that Artisan TPIOL is a safe and predictable method for the correction of high levels of astigmatism.
Alio et al . ( J Refract Surg.2005;21(4):324-31 ) assessed the safety and efficacy of Artisan TPIOLs in eyes with high degrees of compound myopic, hyperopic, and mixed astigmatism. Safety index of the procedure was 1.6, 1.3, and 1.3 in the myopic, hyperopic, and mixed astigmatism groups, respectively. The efficacy index of the procedure was 1.2, 1.0, and 1.0 in the myopic, hyperopic, and mixed astigmatism groups, respectively. They concluded that Artisan TPIOLs are safe for the correction of high degrees of astigmatism associated with myopic or hyperopic spherical refractive error.
Bartels et al . ( J Cataract Refract Surg.2006;32(2):243-9 ) evaluated the Artisan TPIOLs for the correction of hyperopia and astigmatism in 47 eyes of 28 patients. Safety index and efficacy index after six months were 1.06 and 0.87, respectively. They concluded that Artisan TPIOLs can correct moderate to high hyperopia combined with astigmatism with good refractive results. However, the predictability of the refractive results appeared to be lower than those for the correction of myopia and astigmatism with toric Artisan lenses.
Bartels et al . ( Ophthalmology2006;113(7):1110-7 ) evaluated postoperative astigmatism with regard to incision-induced astigmatism and deviation in axial alignment with the use of preoperative limbal marking with Javal keratometer in 54 eyes of 33 patients with myopia (mean: -9.67 D) and astigmatism (mean: -3.44 D) implanted with Artisan TPIOL. Eighty three percent of eyes achieved UCVA of 20/40 and 28% achieved 20/20. Vector analysis of total SIA revealed a mean cylindrical change of 3.21 ± 1.71 D. Average axis misalignment was 0.37 ± 5.34º. The mean incision-induced astigmatism was 0.74 ± 0.61 D at 0.2º. They concluded that a systematic undercorrection of -0.50 D for attempted cylindrical outcome could result in an achieved correction closer to emmetropia.
Mertens et al . ( J Refract Surg.2008;24(5):501-6 ) reported implantation of custom-designed PC TPIOL in a patient with high astigmatism of -5.25D x 6° OD and -5.00 D x 176° OS and achieved a UCVA of 20/20 and best-spectacle corrected visual acuity (BSCVA) of 20/16 in both the eyes at three and six months postoperatively.
| Keratoconus|| |
Leccisotti et al . ( J Cataract Refract Surg.2003;29(8):1530-6 ) in their study noted good visual results with angle-supported PIOLs to correct myopia associated with early stage keratoconus. Endothelial loss at 12 months was 7.2%. Although astigmatism did not improve by the creation of the incision, it was well tolerated by most patients.
Budo et al . ( J Refract Surg.2005;21(3):218-22 ) evaluated the use of Artisan TPIOL for correction of astigmatism and spherical ametropia in patients with keratoconus. Artisan TPIOLs were implanted uneventfully in both eyes of three patients with keratoconus with clear central corneas and contact lens intolerance.
Moshirfar et al . ( J Cataract Refract Surg.2006;32(7):1227-32 ) reported two patients with stable keratoconus and high myopia who benefited from implantation of an iris-supported PIOL (Verisyse, AMO) for correction of their refractive error. Both patients had a postoperative UCVA of 20/40. ECD showed at most a 4% decrease, and no evidence of keratoconus progression was witnessed.
El-Raggal and Abdel Fattah ( J Refract Surg.2007; 33:966-970 ) evaluated the safety, efficacy, and stability of sequential Intacs insertion and Verisyse PIOL implantation in selected cases of keratoconus. All eyes achieved UCVA of 20/40 or better. The final spherical error ranged from -1.75 to +1.00 D, and the cylindrical error from 1.25-2.50 D. No eye lost any line of preoperative BCVA. Sequential Intacs and a Verisyse PIOL implantation were safe, stable, and effective in selected cases of keratoconus.
| Pellucid marginal degeneration|| |
De-Vries et al . ( Cornea 2008;27(2):241-5 ) described a patient who underwent implantation of a Verisyse/Artisan iris-fixated PIOL for correction of high myopia in early pellucid marginal degeneration (PMD). The preoperative refraction of the right eye was -13.0 D/-3.0 D x 90º. The postoperative SE was +0.50 D after one year and +0.50 D after seven years. The preoperative refraction of the left eye was -13.0 D/-1.25 D x 55º. The postoperative SE was -0.38 D after one year and -0.13 D after seven years. Preoperative topographic astigmatism for the right and left eye was 2.94 and 0.81 D, respectively. Seven years later, topographic astigmatism for the right and left eye had changed to 4.45 and 0.71 D, respectively. This case shows that implantation of a Verisyse/Artisan PIOL may be effective in the treatment of refractive error in PMD.
| After penetrating keratoplasty|| |
Tehrani and Dick ( Klin Monatsbl Augenheilkd.2002;219(3):159-63 ) first reported implantation of PIOL for correction of keratoplasty related high astigmatism of 7.6 D x124°, which could not be successfully treated with glasses or contact lenses. An Artisan TPIOL with -3 D spherical and 7.0 D x 0° cylindrical power was implanted via a sclerocorneal tunnel incision into the anterior chamber. Six months after implantation the IOL was well-centered and UCVA was 20/20.
Moshirfar et al . ( J Cataract Refract Surg.2004;30(7):1578-81 ) implanted Artisan PIOL to correct high myopia in two cases after penetrating keratoplasty (PK) with good results.
Tahzib et al . ( Ophthalmology 2006;113(6):976-84 ) implanted Artisan toric iris-fixated PIOL after PK to correct high ametropia and astigmatism in 36 eyes of 35 patients who were contact lens intolerant or unable to wear glasses due to anisometropia and/or high astigmatism. The PIOL was effective for reduction of refractive astigmatism and ametropia. All patients were suitable for spectacle correction after implantation.
| Pediatric ametropia/anisometropia|| |
Chipont et al . ( J Cataract Refract Surg.2001;17(4):460-2 ) reported a case of myopic anisometropic amblyopia in an 8-year-old boy, treated successfully with implantation of an Artisan iris claw phakic anterior chamber IOL, combined with occlusion therapy.
Lesueur et al . ( J Refract Surg.2002;18(5):519-23 ) evaluated anatomical and functional outcomes of ICL for correction of high myopia with amblyopia in 12 eyes of 11 children, aged 3-16 years. Recovery of binocular vision was achieved in six patients and orthotropic position in seven patients. They concluded that PICL is an effective method to treat high myopia in children with amblyopia.
Saxena et al . ( J Cataract Refract Surg.2003;29(4):835-8 ) reported a child with anisometropic amblyopia implanted with artisan iris fixated PIOL. After IOL implantation, the child was put on amblyopia therapy and he had visual acuity of 20/20 after one year.
Tychsen et al . ( JAAPOS 2008;12(3):282-9 ) implanted iris fixated PIOLs in children with high ametropia and neurobehavioral disorders who had chronic difficulties with spectacle and/or contact lens wear. The mean myopic correction was 14.5 D (range: -10.0 to -22.75 D) and hyperopic correction was 9.4 D (range: 10.25-10.75 D) and the mean follow up was 9.1 months. They concluded that PIOL improved visual function substantially in neurobehaviorally impaired children with high ametropia.
BenEzra et al . ( Am J Ophthalmol.2000;130(3):292-6 ) reported a series of three cases of PC PIOL (ICL; STAAR Surgical AG, Nidau, Switzerland) to correct anisometropia. Binocular functions with development of fusional abilities and stereopsis were observed in two of these patients. In the third patient, the fusional abilities developed after surgical correction of the exotropia.
Assil et al . ( J Cataract Refract Surg.2007;33(11):1985-6 ) implanted a Verisyse PIOL in the eye of a 3-year-old child with unilateral high myopia and suspected dense amblyopia. Four years postoperatively, the BCVA was 20/30 with a refraction of -1.00 D/ -1.00 D x 77º. They concluded that Verisyse PIOL may be a treatment option to prevent dense amblyopia in children with high myopic anisometropia.
| After buckling surgery|| |
Chung et al . ( J Refract Surg.2006;22(8):820-3 ) reported three cases of Artisan PIOL implantation for the correction of myopic refractive error after previous buckling surgery for retinal detachment. There was no occurrence of new break, progressive vitreoretinal traction, or any other complications.
Leccisotti A ( Eur J Ophthalmol.2007;17(3):388-91 ) reported a case series of nine eyes of seven patients in which angle-supported PIOL implantation was performed after scleral buckling for retinal detachment. The mean SE before PIOL implantation was -16.36 ± 3.98 D; mean postoperative SE was -0.99 ± 0.51 D with a mean follow-up of 4.2 ± 0.8 years. The surgery was uneventful in all cases. This report showed that in selected eyes with no anterior chamber abnormalities, the implantation of angle-supported PIOL after scleral buckling surgery is associated with good refractive results.
| Presbyopia correction|| |
Alio et al . ( Ophthalmology2005;112(8):1368-74 ) in a pilot study investigated the potential of an anterior chamber phakic refractive multifocal IOL for the correction of near and far vision in those with myopic and hyperopic presbyopia and found good results.
| Investigations|| |
Oh et al . ( Ophthalmology2007;114(9):1685-8 ) determined the correlation of the ciliary sulcus diameter (CSD) measured by 35-megahertz ultrasound biomicroscopy (UBM) with white-to-white distance. They concluded that the posterior chamber has a vertically oval shape and the white-to-white technique is inaccurate at predicting the horizontal diameter of the ciliary sulcus. They further commented that 35-MHz UBM may provide a good means of measuring the CSD for implantation of a PC PIOL.
Choi et al . ( J Refract Surg.2007;23(4):362-7 ) assessed the efficacy of UBM in estimating the sulcus-to-sulcus horizontal diameter, to obtain optimal ICL length and vault for implanting Visian ICL, model V4. They found that ICL length determined by UBM method achieved significantly more ideal ICL vault than that of the conventional white-to-white method.
Rabsilber et al . ( J Cataract Refract Surg.2003;29(11):2115-21 ) evaluated the anterior chamber depth (ACD) according to refractive status, assessed the reliability of repeated ACD measurements using the Orbscan II Topography System, compared Orbscan II and IOL Master ACD measurements, and investigated the correlation between refraction, axial length (AL), and ACD. They concluded that significantly lower ACD values were found in the hyperopia group than in the emmetropia and myopia groups. There was no difference in ACD between the emmetropia and myopia groups even though the AL in the myopia group was 4.0 mm longer. No statistically significant difference in ACD measurements was found between the Orbscan II and IOL Master.
Frisch et al . ( Eur J Ophthalmol.2007;17(3):327-31 ) compared ACD measurements using Orbscan II (Bausch and Lomb, Rochester, NY) and IOL Master (Carl Zeiss Meditec AG, Jena, Germany) and found that both systems were equally good and interchangeable in clinical practice in terms of ACD evaluation.
Lee et al . ( J Refract Surg.2007;23(5):487-91 ) compared the measurement of ACD exclusive of corneal thickness using Orbscan IIz and UBM and evaluated the repeatability of each method. They concluded that the mean ACD with Orbscan IIz was 0.087 mm less than that with UBM and both methods were precise. Orbscan IIz seems to be a useful and more convenient method to measure ACD for PIOL implantation.
Kim et al . ( J Cataract Refract Surg.2008;34(4):632-7 ) evaluated correlations between horizontal CSD measured by 35-MHz UBM and other ocular measurements. They found that mean corneal curvature was significantly and negatively correlated with horizontal sulcus diameter. They derived regression formula based on mean corneal curvature measurements that may help predict sulcus diameters for proper sizing of PC PIOL.
Savant et al . ( J Refract Surg.2008;24(6):615-8 ) assessed the comparability and intra-/ inter-observer reliability of central ACD measurements obtained by Pentacam and IOL Master and found that good agreement exists between the two modalities and the two are interchangeable.
| Complications|| |
Ardjomand et al . ( J Cataract Refract Surg.2002;28(6):1080-1 ) described pupillary block after phakic anterior chamber IOL (NuVita, Bausch and Lomb) implantation. The anterior chamber deepened again, and the IOP decreased to 16 mm Hg after a Nd:YAG iridotomy. They advocated prophylactic peripheral iridotomy in cases of PIOL surgeries.
Smallman et al . ( J Cataract Refract Surg.2004;30(4):905-7 ) described development of pupillary block glaucoma in patient implanted with PC PIOL for high myopia in both eyes. Laser peripheral iridotomy was already performed before the surgery in both eyes and the IOL implantation was performed uneventfully. The IOLs were subsequently removed due to development of further attack of pupillary block glaucoma despite apparently patent iridotomies.
Kodjikian et al . ( J Cataract Refract Surg2002;28(12):2217-21 ) described a case of malignant glaucoma induced by a PC PIOL for myopia. The patient was implanted with ICM130 V2 myopic PIOL (Staar Surgical AG) in the posterior chamber for myopia of -14.00 D. Three days later, the patient developed malignant glaucoma. Pupillary block glaucoma and choroidal hemorrhage or effusion, were ruled out. Maximum medical treatment failed, and a sclerotomy with aspiration in the mid-vitreous cavity, and removal of the IOL was performed.
Sanchez-Galeana et al . ( Am J Ophthalmol 2002;134(1):121-3 ) described a case which developed pigmentary glaucoma resulting from the implantation of a PC PIOL. The intraocular pressure did not respond to medical therapy and even IOL removal. Trabeculectomy was required to reduce the pressure.
Vetter et al ( J Cataract Refract Surg 2006;32(6):1065-7 ) reported a case of pupillary block within 24 hours after implantation of an ICL due to inappropriate sizing of ICL. Immediate explantation of the ICL was performed. Then, using preoperative iris photography as guidance, an anterior chamber iris-claw TPIOL was implanted. On postoperative examination, the anterior chamber was deep, the angle open, the natural lens clear, and UCVA was 20/40.
| Corneal decompensation|| |
Marcon et al . ( J Fr Ophtalmol 1996;19(2):149-52 ) reported a case of silicon IOL in the posterior chamber for the correction of myopia in phakic eye. One year after surgery there was total bilateral corneal decompensation which required corneal transplantation.
Patel et al . ( J Cataract Refract Surg.2005;31(11):2212-5 ) reported three patients who experienced corneal decompensation and cataract progression following angle-fixated AC PIOL placement.
Coullet et al . ( J Cataract Refract Surg 2007;33(8):1477-81 ) reported three eyes in which the foldable angle-supported PIOL was implanted to correct high myopia. Rapid and severe postoperative ECL occurred in all three eyes. An over-sized PIOL that induced excessive vaulting into the anterior chamber was the main risk factor. In two eyes, the PIOL was explanted uneventfully; one eye required Descemet's stripping automated endothelial keratoplasty because of total endothelial decompensation.
Kim et al . ( J Cataract Refract Surg2008;34(3):517-9 ) reported a case of corneal decompensation following iris-claw PIOL (Artisan, Ophtec) implantation.
Saxena et al . ( Ophthalmology2008;115(4):608-613 ) reported correlation of ECD to ACD after implantation of Artisan iris-fixated PIOL in 318 eyes of 173 myopic patients. After three years, a significant ECD loss was revealed. This ECD loss was significantly negatively correlated to the ACD. Therefore, they suggested that eyes just meeting the minimum ACD requirement should have greater ECD to compensate for a possible greater ECL. Artisan phakic lens implantation in young eyes narrowly meeting the minimum criteria of ECD (2,000 cells/mm 2 ) and ACD (2.6 mm) should perhaps be reevaluated, due to longer exposure to higher rates of ECL.
| Cataract formation|| |
Chen et al . ( J Cataract Refract Surg2008;34(7):1181-1200 ) performed a systematic literature review to determine the incidence of and predisposing factors for cataract after PIOL implantation. Of the 6338 eyes reported, 4.35% were noted to have new-onset or progression of preexisting cataract. The incidence of cataract formation was 1.29%, 1.11%, and 9.60% with anterior chamber, iris-fixated, and PC PIOLs, respectively. The rate of progression of preexisting cataract was 29.5% after PIOL surgery.
Guell et al . ( J Cataract Refract Surg2007;33(8):1398-404 ) studied dynamics of the relationship between Verisyse (AMO) and Artiflex (Ophtec B.V.) PIOLs and anterior chamber structures during accommodation, using optical coherence tomography (OCT) (Visante, Carl Zeiss Meditec, Inc.). They noted a decrease in the distance between the PIOL and corneal endothelium, whereas the distance between PIOLs and the crystalline lens remained constant in the accommodative state. This suggests that the risk for cataract from intermittent contact between the crystalline lens and IOL from accommodative effort is unlikely with Verisyse or Artiflex PIOLs.
Koivula et al . ( Ophthalmology2007;114(11):2031-7 ) evaluated the dynamics of the phakic refractive lens (PRL) in myopic and hyperopic eyes in the nonaccommodated state and during subjective accommodation with Visante OCT. The PRL moved forward during accommodation in all the eyes, with some distance preserved between the PRL and the anterior lens surface (ALS). In 85% of cases, there was no mechanical contact with the ALS during accommodation.
| Retinal detachment|| |
Ruiz-Moreno et al . ( Am J Ophthalmol1999;127(3):270-5 ) studied 166 consecutive eyes (98 patients) that underwent implantation of AC PIOL for the correction of severe myopia (follow-up: 45.26 ± 14.65 months). Retinal detachment (RD) occurred in eight eyes (4.8%). The time between implanting surgery and RD was 17.43 ± 16.4 months. In seven eyes, the retina was reattached successfully with single RD surgery.
Martinez-Castillo et al . ( Ophthalmology2005;112(4):580-5 ) reported a 2.07% incidence of rhegmatogenous RD after PC PIOL implantation. The characteristics of RRD did not differ from the natural history of retinal detachment and surgery was successful.
Ruiz-Moreno et al ( J Refract Surg.2006;22(3):247-52 ), in their series, reported an incidence of 2.87% of RD occurring after PIOL implantation. They reported a higher risk in eyes with axial length >30.24 mm.
| Contrast sensitivity and aberrations after phakic intraocular lens|| |
Lombardo et al . ( Ophthalmology2005;112(2):278-85 ) determined the effects of Artisan iris-fixated PIOL implantation on contrast sensitivity in 49 eyes of 30 patients with myopia and myopia with astigmatism. They found that contrast sensitivity was increased under photopic conditions and slightly decreased under mesopic conditions.
Chung et al . ( Ophthalmologica 2007;221(3):167-72 ) evaluated higher-order aberrations (HOAs) and contrast sensitivity (CS) after implantation of Artisan PIOL for high myopia (greater than -8.00 D) in 25 eyes of 15 patients. They showed a small increase of HOAs under photopic conditions. At one month, CS was decreased, but returned to baseline at three months under photopic conditions.
Yu et al . ( Ophthalmologica2008;222(1):53-7 ) in their study, reported that in comparison to PC PIOLs, angle-supported and iris-fixated PIOLs seem to produce a better visual quality in terms of CS.
| Traumatic dislocation of iris fixated phakic intraocular lens|| |
Yoon et al . ( J Refract Surg.2002;18(4):481-3 ) reported a case of dislocation of iris fixated PIOL following blunt trauma, which was later repositioned, and the claw was re-enclaved to the iris.
de Sanctis et al . ( J Refract Surg.2008;24(5):546-8 ) evaluated long-term ECL after traumatic dislocation and repositioning of an Artisan PIOL. They found that progressive and long-term endothelial loss after traumatic dislocation and repositioning of the Artisan PIOL may be comparable to that reported after uneventful implantation.
| Causes of phakic intraocular lens explantation|| |
Alio et al . ( Ophthalmology2006;113(12):2213-20 ) in their study ( N = 100) reported that the main causes of PIOL explantation were cataract development ( n = 64; 64%), progressive ECL (24%), and pupil ovalization (10%).The mean time between IOL implantation and explantation due to cataract was 10.04 ± 3.66 years and the same due to progressive ECL was 8.97 ± 2.21 years.
Guell et al . ( Ophthalmology2008;115(6):1002-12 ) in their five-year experience of 399 Verisyse PIOL implantations, reported three explantations due to an unacceptable ECL, three repositioning of lens (two ocular trauma and one inappropriate iris capture), and three lens exchange due to refractive errors.
| Post phakic intraocular lens phacoemulsification|| |
Alio et al . ( J Cataract Refract Surg.2000;26(9):1303-11 ) implanted angle-supported PIOLs in 263 eyes of 160 patients. Nuclear cataract developed in nine cases (3.42%) after 42.91 ± 17.7 months after implantation. PIOL explantation, phacoemulsification, and PC IOL implantation were successfully performed.
| Comparison of phakic intraocular lenses versus excimer laser procedures|| |
Chandhrasri et al . ( J Refract Surg.2006;22(3):231-6 ) evaluated HOAs and CS after LASIK ( n = 20), implantation of the Verisyse PIOL ( n = 11), and refractive lens exchange with Array multifocal IOL ( n = 12). They concluded that all three increase HOAs at large pupil sizes, but no increase was noted at small pupil sizes with LASIK or the Verisyse IOL. CS in photopic conditions was normal with LASIK and Verisyse IOL, but slightly reduced with Array IOL.
Tsiklis et al . ( J Refract Surg.2007;23(9):935-7 ) compared the long-term results (nine years) of LASIK in one eye and PIOL (ICL) in the fellow eye of the same patient. At nine years, the mean SE was -1.00 D in the eye with the ICL and -1.75 D in the eye that underwent LASIK. During the first six postoperative months in the LASIK eye, refraction regressed, but remained stable during the remainder of follow-up. The UCVA was 20/25 in the eye with ICL and 20/30 in the LASIK eye, whereas BSCVA was 20/20 in both eyes. Less night vision problems (glare and halos) were experienced in the eye with ICL. Nine years after treatment of high myopia with the ICL and LASIK in the same patient, better quality of vision, stability, and satisfaction score were achieved in the eye with the ICL.
Schallhorn et al . ( J Refract Surg2007;23(9):853-67 ) compared TPIOL and photorefractive keratectomy (PRK) in the correction of moderate to high myopic astigmatism. The TPIOL performed better than PRK in terms of safety (BSCVA), efficacy (UCVA), predictability, and stability.
Kamiya et al . ( Nippon Ganka Gakkai Zasshi.2008;112(6):519-24 ) compared the modulation transfer function and the retinal magnification after myopic correction by spectacles, LASIK, and PIOL implantation. There was no significant difference in the modulation transfer function after PIOL implantation and LASIK. The retinal magnification was least affected by PIOL implantation, more affected by LASIK, and most affected by spectacle correction.
Meltendorf et al . ( Ophthalmologica2008;222(2):69-73 ) performed LASIK for correction of residual refractive errors following implantation of iris-fixated PIOLs. They concluded that LASIK was safe and effective in such eyes.
Guell et al . ( J Refract Surg.1999;15(5):529-37 ) evaluated the results of combined surgery, implantation of an Artisan phakic iris claw IOL followed by LASIK to correct high myopia. They reported accurate refractive outcome, absence of major complications, stability of results, and improvement in quality of vision.