Fellow-eye comparison of posterior capsule opacification with AcrySof SN60AT and AF-1 YA-60BB blue-blocking intraocular lenses.

PURPOSE: To evaluate intraindividual differences in posterior capsule opacification (PCO) and visual performance of AcrySof SN60AT (Alcon Laboratories) and AF-1 YA-60BB (Hoya Corp.) intraocular lenses (IOLs). SETTING: Ophthalmology Department, St. Thomas' Hospital, London, United Kingdom. METHODS: In this prospective single-surgeon standardized-surgical-procedure fellow-eye comparison, an AcrySof SN60AT or an AF-1 YA-60BB IOL was randomized to the first eye of 36 patients and fellow-eye surgery was performed within 4 to 6 weeks. Follow-up was at 1, 3, 6, 12, and 24 months. Best distance- corrected logMAR visual acuity was measured at 100% and 9% contrast. Contrast sensitivity was measured using the Functional Acuity Contrast Test (FACT) on the Optec 3500 instrument (Stereo Optical Company, Inc.). Color vision was assessed with the Farnsworth Munsell 100-hue test. After pupil dilation, digital retroillumination photographs were taken and the percentage area of PCO was calculated using POCO software. RESULTS: Posterior capsule opacification was significantly greater in the AF-1 YA-60BB group than in the AcrySof SN60AT group at all time points (P<.0001), with the difference greatest at 24 months. At 24 months, 100% contrast visual acuity was significantly better in the AcrySof SN60AT group than in the AF-1 YA-60BB group (P = .0313); 9% contrast visual acuity was significantly better in the AcrySof SN60AT group from 6 months onward. There was no significant difference between groups in color vision or contrast sensitivity. Electron microscopy showed the AcrySof SN60AT IOL has a much sharper posterior edge profile. CONCLUSIONS: The AcrySof SN60AT IOL had better PCO performance and thus visual performance than the AF-1 YA-60BB IOL. This is attributable to the differences in optic edge design.

Effect of intraocular lens edge profile on posterior capsule opacification after extracapsular cataract surgery in a developing country.

PURPOSE: To determine whether square-edged polymethyl methacrylate (PMMA) intraocular lenses (IOLs) reduce posterior capsule opacification (PCO) in the context of extracapsular cataract surgery in a developing country. SETTING: A rural hospital in India. METHODS: This was a prospective randomized double-masked fellow-eye controlled study. Over a 4-month period, 118 patients with normal eyes apart from age-related cataract were randomized to receive a square-edged or round-edged PMMA IOL in the first eye. The IOLs were identical apart from the edge profile. The fellow-eye had implantation of the alternative IOL within 1 month. Retroillumination images of the posterior capsule were taken using a dedicated camera system and analyzed to quantify the PCO area using POCO software 1 and 2 years postoperatively and the PCO area and severity using POCOman semiqualitative software at 2 years. Visual acuity was measured using a Gujarati logMAR chart. RESULTS: One hundred fifteen patients were available for examination at 1 year and 107 at 2 years. With POCO software, the PCO area was reduced in the square-edged IOL group at 1 year (median 30% versus 20%, P=.001) and at 2 years (median 45% versus 35%, P=.006). With POCOman, the PCO area and severity were reduced in the square-edged group at 2 years (median 41.5% versus 33.2%, P=.019 and 0.59 versus 0.46, P=.037, respectively). There was no significant difference in visual acuity between the 2 groups at 1 or 2 years. CONCLUSIONS: Sophisticated image analysis techniques can be used in developing countries to quantify PCO. Using extracapsular surgery, square-edged PMMA IOLs reduced the PCO area and severity compared with an identical round-edged IOL; however, the differences were not as marked as those reported with phacoemulsification. This may be due to the difficulty of performing a capsulorhexis that lies on the IOL surface in this situation. Nevertheless, square-edged IOLs offer a potential benefit for extracapsular surgery in the developing world.

Fellow-eye comparison of posterior capsule opacification rates after implantation of 1CU accommodating and AcrySof MA30 monofocal intraocular lenses.

PURPOSE: To measure posterior capsule opacification (PCO) and neodymium:YAG (Nd:YAG) capsulotomy rates between the AcrySof MA30 intraocular lens (IOL) (Alcon) and the 1CU IOL (HumanOptics) in a fellow-eye comparison. SETTING: Ophthalmology Department, St. Thomas' Hospital, London, United Kingdom. METHODS: Thirty patients who had bilateral cataract surgery with a 1CU IOL prospectively randomly allocated to 1 eye and an AcrySof MA30 monofocal IOL to the other eye were examined. Best corrected distance visual acuity was recorded using the Early Treatment Diabetic Retinopathy Study logMAR chart. Digital retroillumination images of the posterior capsule were taken with the pupil dilated and analyzed with POCO software. RESULTS: Eyes with the 1CU IOL had significantly higher PCO rates than eyes with the MA30 IOL at all time points. By 2 years after surgery, 50% of eyes with a 1CU IOL had required Nd:YAG capsulotomy compared with no eyes with an MA30 IOL. There was no significant difference in visual acuity at any time point when post Nd:YAG capsulotomy was taken in to account. CONCLUSIONS: The 1CU IOL has 4 broad optic-haptic junctions where the square-edged barrier is breached; this appeared to allow passage of lens epithelial cells, leading to an increase in PCO. However, the increased PCO cannot be attributed to this alone as the 1CU is hydrophilic, a factor known to be associated with higher PCO rates.

Hydrophobic acrylic and plate-haptic silicone intraocular lens implantation in diabetic patients: pilot randomized clinical trial.

PURPOSE: To compare the capsular and uveal reaction after implantation of a plate-haptic silicone intraocular lens (IOL) (C11UB, Chiron) and a hydrophobic acrylic (AcrySof MA60, Alcon) IOL in diabetic patients. SETTING: Moorfields Eye Hospital and St. Thomas' Hospital, London, United Kingdom. METHODS: Thirty-five diabetic patients were recruited consecutively and randomly assigned to have implantation of either of the 2 IOLs. The percentage area of posterior capsule opacification (PCO), anterior capsule contraction (ACC), and postoperative inflammatory indices (flare and cells) were assessed objectively at 2 to 3 weeks, 6 months, and 1 year. Between-group and within-group analyses were conducted using the Student t test or Mann-Whitney test and Friedmann test, respectively. RESULTS: Between-group analysis showed the percentage area of PCO was significantly greater in patients with plate-haptic silicone IOLs at 6 and 12 months (P = .002). At 6 months, ACC was significantly greater in the plate-haptic group (P = .04), but the difference was not significant at 12 months. There was higher flare in the hydrophobic acrylic IOL group than in the plate-haptic silicone IOL group at 2 to 3 weeks (P = .08). Within-group analysis showed that over the follow-up period, the plate-haptic silicone group, but not the hydrophobic acrylic group, had a progressive increase in PCO (P = .003). In the hydrophobic acrylic group, but not the plate-haptic silicone group, there was a significant reduction in the mean anterior chamber flare value (P = .01). There was no significant difference in visual acuity or contrast sensitivity at any postoperative visit. CONCLUSION: In diabetic patients, hydrophobic acrylic IOLs can lead to an increased flare in the early postoperative period but they seem to be more favorable than plate-haptic silicone IOLs because the latter lead to more PCO.

Fellow eye comparison between the 1CU accommodative intraocular lens and the Acrysof MA30 monofocal intraocular lens.

PURPOSE: To examine the near visual clinical performance of an accommodative intraocular lens (IOL) when compared with a standard monofocal IOL in a fellow eye comparison. DESIGN: Prospective, randomized fellow eye comparison. METHODS: Thirty patients (60 eyes) with bilateral cataracts but otherwise normal eyes were recruited from a single university hospital cataract waiting list. Patients were randomized to receive either the 1CU accommodative IOL in their first eye or the Acrysof MA30 monofocal IOL. The alternative lens was then implanted in the second eye 4 to 6 weeks later. At all follow-up visits, a full assessment was made of distance, near and reading visual performance, and accommodative amplitude. RESULTS: Data are available for all patients at 6 months and 20 patients at 1 year. At 6 months, no difference was found in distance-corrected visual acuity between the two IOLs. Of the 1CU eyes, nine patients (30%) could read J6 or better at a reading speed of 80 words/min or better. In these nine patients, the mean difference in the amplitude of accommodation between the two eyes was 0.71 diopters. CONCLUSIONS: No measurable variable distinguished eyes that developed functional reading vision from those that did not. The accommodative IOL appears to produce improved near vision in some eyes, but it does not work in all eyes, and in eyes where there is apparent accommodation, there is a discrepancy between subjective reading performance and the modest measured increase of accommodative amplitude.

Factors that influence the development of posterior capsule opacification with a polyacrylic intraocular lens.

PURPOSE: To identify factors that contribute to posterior capsule opacification (PCO) after implantation of a 5.5 mm polyacrylic (IOL). DESIGN: A retrospective analysis of a cohort of sequential images taken from the PCO database at St. Thomas' Hospital, London, to include all patients with an AcrySof MA30 lens and a 1-year retroillumination image. METHODS: Records of age, gender, axial length, and PCO measurements using the POCO software system were available. Images were divided into those with greater or less than 10% PCO. The degree of rhexis-IOL contact was recorded in clock hours. RESULTS: Images of 60 eyes were analyzed. Twenty-one eyes had more than 10% PCO. No correlation was found between PCO and age, gender, or axial length. Forty-eight eyes (80%) had some loss of rhexis-IOL contact. These eyes had increased PCO (P < .001) compared with eyes with complete IOL-rhexis contact. More PCO developed when the rhexis was partly on and partly off the IOL. CONCLUSIONS: PCO is reduced when the rhexis is in complete contact with the anterior IOL surface. The failure to achieve this accounts for the majority of increased PCO seen in patients implanted with this IOL model. PCO formation is related to surgical technique as well as IOL design, and comparisons cannot be made between IOLs without taking this into consideration. These results support the trend to the use of larger optic IOLs to prevent PCO and also support the "capsule compression" theory of PCO prevention.

Comparison of posterior capsule opacification rates between hydrophilic and hydrophobic single-piece acrylic intraocular lenses.

PURPOSE: To determine the effect of intraocular lens (IOL) material on the development of posterior capsule opacification (PCO) at 1 year. SETTING: Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom. METHODS: One hundred six eyes of 53 patients with bilateral cataract and no other ocular comorbidity were prospectively randomized to receive a hydrophobic acrylic or hydrophilic acrylic single-piece IOL in the first eye to have surgery. The alternate IOL was implanted in the fellow eye 4 to 6 weeks later. All surgery was performed by a single surgeon. Postoperative follow-up was 1 day, 1 and 6 months, and 1 year. At each visit, the best corrected high- and low-contrast visual acuities were assessed and a high-intensity digital retroillumination photograph was taken. Posterior capsule opacification was assessed from the digital images by a single operator using a dedicated software program and calculated as the percentage area of opacified capsule. RESULTS: One year postoperatively, the median percentage area of PCO was 50.3% in the hydrophilic IOL group and 4.9% in the hydrophobic IOL group (P<.001). The difference in PCO was not accounted for by loss of contact between the capsulorhexis and IOL surface. Further analysis showed that lens epithelial cells tended to invade the posterior capsule at the haptic-optic junction. This was more marked in the hydrophilic IOL group. CONCLUSIONS: The rate of PCO was significantly higher with the hydrophilic IOL. However, the results cannot be attributed to the IOL material alone as they show the importance of both IOL material and design.

In vitro model for the study of human posterior capsule opacification.

PURPOSE: To develop and evaluate a model for the organ culture of human lens capsules that reduces problems inherent in preexisting models for the study of in vitro posterior capsule opacification (PCO). METHODS: Human lenses (N = 110) were isolated from donor eyes and supported externally within a lens holder system by medical-grade cyanoacrylate glue, allowing visualization of the entire capsular bag. After capsulorhexis and lens extraction were performed, the capsule specimens were maintained at physiological conditions for up to 4 weeks. The area of lens epithelial cell (LEC) coverage over the posterior capsule surface was determined objectively on a daily basis using a graticule. Lens epithelial cell behavior was correlated with clinical data and other in vitro PCO models. RESULTS: Cyanoacrylate glue did not appear to be toxic to LECs at the concentration used. The amount of viable epithelium after nuclear extraction was dependent on the age and postmortem time of the specimen. Viable LEC cultures were obtained from eyes up to 9 days postmortem. The time from death to culture or from enucleation to culture did not influence LEC viability if it was fewer than 5 days. The LEC proliferation rates and confluence times were age dependent and correlated closely between pairs of eyes. CONCLUSIONS: Results show that the lens holder model is a more physiological method for supporting the capsule and is a robust, reproducible system for the study of LEC migration and proliferation. It allows visualization within the entire capsular bag. Intraocular lenses can be implanted in this system in a way that more closely resembles the in vivo scenario. This model can be used to evaluate therapeutic measures to prevent PCO.

Predicting posterior capsule opacification: value of early retroillumination imaging.

PURPOSE: To investigate the value of early retroillumination imaging of the posterior capsule in predicting the eventual development of posterior capsule opacification (PCO). SETTING: Ophthalmology Department, St. Thomas' Hospital, and Department of Physics, King's College, London, United Kingdom. METHODS: All patients with retroillumination images of the posterior capsule taken 6 months and 2 years after uneventful phacoemulsification with in-the-bag intraocular lens (IOL) implantation were selected. The images were taken using the same hardware and analyzed with the same software to calculate the percentage area of the posterior capsule covered by lens epithelial cells. The percentage area of PCO with all IOL types 6 months postoperatively was correlated with that at 2 years. RESULTS: One hundred forty patients had analyzable images at 6 months and 2 years. Of these, 63 had a poly(methyl methacrylate) (PMMA) IOL (Pharmacia 812A or Storz P497UV), 33 an acrylic (Alcon AcrySof MA30 or SA30), 22 a silicone (Allergan SI-30), and 22 a hydrophilic acrylic (Bausch & Lomb Hydroview H60). The correlation of the percentage area of PCO at 6 months with that at 2 years resulted in an r value of 0.71 (P <.0001) in the entire group. The r value was 0.48 in the PMMA group and 0.86 in the foldable IOL group (P <.0001) (r value: AcrySof, 0.66; silicone, 0.82; Hydroview, 0.75). CONCLUSIONS: Retroillumination imaging of the posterior capsule 6 months after cataract surgery predicted the PCO outcome at 2 years in eyes with foldable IOLs.

Effect of 1-piece and 3-piece AcrySof intraocular lenses on the development of posterior capsule opacification after cataract surgery.

PURPOSE: To evaluate the effect of 1-piece and 3-piece hydrophobic acrylic intraocular lenses (IOLs) on posterior capsule opacification (PCO) after cataract surgery. SETTING: Ophthalmology departments of 3 hospitals in the United Kingdom and Germany and the Department of Physics at a United Kingdom university. METHODS: A series of 131 patients having cataract surgery had implantation of an acrylic 1-piece (SA30AL) or an acrylic 3-piece (MA30BA) IOL (AcrySof, Alcon). Surgery was performed according to standardized protocol by a single surgeon at each hospital. Posterior capsule opacification was assessed using digital retroillumination photography. All images were analyzed at a single center according to a standard protocol. Data were analyzed 6 months and 1 year after surgery. RESULTS: There was no statistically significant difference in the percentage area of PCO between the 1-piece (mean 16.0% +/- 15.7% [SD]) and 3-piece (mean 13.6% +/- 19.8%) cohorts 6 months and 1 year after surgery (P =.0664). CONCLUSION: There was no evidence of a difference in the area of PCO after cataract surgery between 1-piece and 3-piece IOLs, which were otherwise matched for material and lens geometry.

Effect of intraocular lens asphericity on posterior capsule opacification between two intraocular lenses with same acrylic material: a fellow-eye study.

PURPOSE: To evaluate intra-individual differences in posterior capsule opacification (PCO) and visual performance between spherical AcrySof SN60AT and an aspheric AcrySof SN60WF intraocular lens (IOL) with a posterior aspheric surface, both of which are made of same hydrophobic acrylic material. SETTING: Ophthalmology Department, St Thomas' Hospital, London, UK. METHODS: In this prospective randomized, fellow-eye comparison, an aspheric IOL, which is 9% thinner in comparison with the spherical IOL, was randomized to the first eye of 47 patients and fellow-eye surgery was performed within 3 weeks. Follow-up was at 1, 3, 6, 12 and 24 months. Corrected logMAR visual acuity (CDVA) was measured at 100% and 9% contrast. After pupil dilation, digital retroillumination photographs were taken and the mean PCO percentage was calculated using poco software at each follow-up visit. RESULTS: At 1, 3, 6, 12 and 24 months, 47 (94 eyes), 44 (88 eyes), 42 (84 eyes) and 41 (82 eyes) patients were followed-up respectively. Hundred per cent and 9% of LogMAR CDVA was not significantly different between the two IOLs (p = NS at all time-points). Percentage area PCO scores (mean ± SD) at 1, 3, 6, 12 and 24 months with the spherical IOL was 5.82 ± 9.89, 7.76 ± 16.83, 7.21 ± 12.46, 9.29 ± 18.25 and 14.39 ± 25.42, respectively, and with an aspheric IOL was 8.91 ± 12.79, 5.97 ± 10.32, 5.15 ± 7.92, 7.68 ± 11.18 and 12.18 ± 20.10, respectively (p = NS at all time-points). CONCLUSIONS: Posterior capsule opacification was not significantly different between the spheric and aspheric IOLs in this fellow-eye, randomized comparison. Additional asphericity on the existing model of IOL does not influence PCO performance.

Influence of different acrylic intraocular lens materials on optical quality of vision in pseudophakic eyes.

PURPOSE: To analyze the effect of hydrophobic and hydrophilic acrylic intraocular lens (IOL) material on the optical quality in pseudophakic eyes with a clear posterior capsule and assess in vitro forward light scatter of these IOLs. SETTING: St. Thomas' Hospital, London, United Kingdom. DESIGN: Comparative case series. METHODS: Eyes with a hydrophobic or hydrophilic acrylic IOL and a clear posterior capsule within the central 4.0 mm at least 3 months postoperatively were identified from 2 ongoing studies. Data on 100% and 9% logMAR corrected distance visual acuities (CDVA) and total eye aberrations with a 4.0 mm pupil were collected. The 10% and 50% point-spread function (PSF) values of double-pass measurements were collected. In vitro forward light scattering was analyzed for the IOL models using a standardized laboratory technique. RESULTS: Twenty-eight eyes had hydrophilic IOLs, and 43 had hydrophobic IOLs. There was no significant difference in IOL power, postoperative spherical equivalent, or 100% logMAR CDVA between hydrophilic IOLs and hydrophobic acrylic IOLs. Nine percent logMAR CDVA (P=.000), 10% PSF (P=.005), 50% PSF (P=.008), and Zernike polynomial 4 (P=.000) were significantly different between the IOL groups. Although in vitro forward-scatter levels were low in both groups, hydrophilic IOLs had more forward scatter. CONCLUSIONS: Hydrophobic acrylic IOLs gave better low contrast visual acuity. Even within the acrylic subgroup, the optical quality varied significantly. The IOL material is an important factor influencing the optical quality of vision with different acrylic IOLs.

Islands of lens epithelial cells on the posterior capsule in pseudophakic eyes.

PURPOSE: To evaluate the natural history of focal collections (islands) of lens epithelial cells (LECs) on the posterior capsule after cataract surgery. SETTING: Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom. METHODS: Patients in previous studies with various intraocular lenses (IOLs) and at least a 2-year follow-up were identified. Postoperative digital retroillumination images of each eye taken at 1, 3, and 6 months and 1 and 2 years were assessed for the presence of LEC islands and their incidence, etiology, time of appearance, change with time, and relationship to IOL material. RESULTS: Islands of LECs were identified in 39 eyes with an AcrySof SA60AT IOL, 40 eyes with a Rayner Centerflex C570H IOL, and 27 eyes with a Hoya YA60BB IOL. In all groups, the islands tended to appear within 6 months with a decreasing incidence thereafter. Floating LECs that seeded on the posterior capsule (seeded LECs) or LECs left on the posterior capsule at surgery were seen in a small number of eyes. Most islands were derived from regression of a previous LEC membrane, and a majority continued to regress. Intraocular lens material had no influence on the natural history or morphology of the islands. CONCLUSION: Islands of LECs were common postoperatively. Equatorial LECs appeared to be the major cause of clinical posterior capsule opacification (PCO). Floating LECs in the aqueous that seeded on the posterior capsule or LECs left behind after surgery did not appear to contribute to clinical PCO. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Randomized intraindividual comparison of posterior capsule opacification between a microincision intraocular lens and a conventional intraocular lens.

PURPOSE: To evaluate the differences in posterior capsule opacification (PCO) and visual and optical performance between a microincision intraocular lens (IOL) and a conventional IOL. SETTING: Ophthalmology Department, St. Thomas' Hospital, London, United Kingdom. METHODS: Patients with bilateral cataract were prospectively randomized to receive a HumanOptics MC611MI microincision IOL (microlens group) or an Alcon AcrySof MA60AC 3-piece IOL (control group) in either eye and were followed for 24 months. Best corrected visual acuity (BCVA) (logMAR) was measured; PCO was quantified by POCO software analysis of retroillumination images. Aberrations and modulation transfer function (MTF) were measured at the 24-month visit. RESULTS: The study enrolled 32 patients. The mean percentage area PCO was greater in the microlens group than in the control group from 3 months onward and was statistically significant from 12 months onward. The greatest difference in PCO between groups was at 24 months: mean 25.45%+/-34.51% (SD) in the microlens group versus 7.82%+/-13.35% in the control group (P= .029). The BCVA in the control group was slightly better at all time points; the difference between groups was statistically significant at 3, 6, and 12 months. No significant difference in aberrations was detected. The MTF curves were comparable for both IOLs. CONCLUSIONS: Both IOLs provided good visual performance. There was no evidence of distortion of the microincision IOL in the capsular bag. The microincision IOL had poorer PCO performance, which was visually significant and was caused by migration of lens epithelial cells through its broad optic-haptic junctions.