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.     

The effects of three-piece or single-piece acrylic intraocular lens implantation on posterior capsule opacification

PURPOSE: To evaluate the development of posterior capsule opacification (PCO) in patients implanted with 5.5 mm optics, single-piece or three-piece acrylic intraocular lens (IOL) in cataract surgery prospectively. METHODS: This study was carried out on 267 eyes of 249 patients implanted with three-piece, 5.5 mm optics, acrylic IOL and 252 eyes of 244 patients implanted with single-piece, 5.5 mm optics, acrylic IOL by phacoemulsification technique between September 2001 and February 2003. A total of 519 eyes of 493 patients were prospectively evaluated for PCO development during the 25-month period. All the patients were analyzed periodically with anterior segment retroillumination photography. The data provided were analyzed with chi-square method. RESULTS: The results between the two groups for PCO development were not statistically significant. However, there was a prominent opacification of the posterior capsule where the optic and haptic junction of IOL was positioned in some patients implanted with single-piece IOL. During the follow-up period, no patients implanted with either three-piece or single-piece acrylic IOL required Nd:YAG laser capsulotomy. CONCLUSIONS: Biocompatibility and reduced rate of PCO development are among the leading features of new generation IOLs. The intracapsular implantation of 5.5 mm optics acrylic IOLs resulted in decreased incidence of PCO and therefore greater patient satisfaction. Further studies investigating the effects of IOL optics, haptic structure and length, capsulorrhexis size, and IOL material and design features on PCO development will clarify the subject.     

A clinical comparison of single-piece and three-piece truncated hydrophobic acrylic intraocular lenses

PURPOSE: To determine the clinical differences between three-piece (3P) and single-piece (SP) truncated hydrophobic acrylic intraocular lenses (IOL). DESIGN: Retrospective cohort clinical study. METHODS: The setting was an academic clinical practice. The patient population consisted of subjects without confounding comorbidity that could effect central vision with at least 1-year follow-up after uncomplicated surgical placement of 3P or SP IOLs in the capsular bag and at least 20/25 best-corrected postoperative vision documented. Observation procedures were as follows: logarithm of the minimal angle of resolution (LogMAR) visual acuity (uncorrected and best corrected), digital retroillumination photographs to ascertain posterior capsular opacification (PCO), anterior capsular opacification (ACO), IOL centration, and refractive stability by comparing this refraction with the early postoperative refraction. Patients completed a dysphotopsia questionnaire. Main outcome measures were as follows: LogMAR visual acuity (uncorrected and best corrected), PCO, ACO, IOL centration, refractive stability, and dysphotopsia outcomes comparing 3P and SP. RESULTS: Seventy-five patients were enrolled (36 3P and 39 SP). Corrected and uncorrected visual acuity, refractive stability, and IOL centration were similar. Single piece truncated hydrophobic acrylic intraocular lenses had more PCO (P =.013), less ACO (P =.001), less central flash looking at a peripheral light (P =.044), and less unwanted images to the side of a light source (P =.025) . CONCLUSIONS: Although similar in centration and refractive stability, SP has more PCO, less ACO, and less dysphotopsia than 3P.     

Effect of the optic size of a single-piece acrylic intraocular lens on posterior capsule opacification

PURPOSE: To investigate the effect of the optic size of an intraocular lens (IOL) with sharp optic edges on posterior capsule opacification (PCO). SETTING: Nishi Eye Hospital, Osaka, Japan. METHODS: In 5 rabbits, a single-piece 5.5 mm optic AcrySof IOL (Alcon Laboratories) was implanted in 1 eye and a specially fabricated single-piece 7.0 mm optic AcrySof IOL was implanted in the contralateral eye. Histopathological examinations were performed 3 weeks after surgery. RESULTS: On posterior views, less PCO was noted with the 5.5 mm optic in all rabbits except 1. Histopathological sections demonstrated adhesion of the anterior and posterior capsules between the haptic and optic and the formation of a sharp capsular bend at the posterior optic edge in 3 eyes with the 5.5 mm optic but in no eye with the 7.0 mm optic. Abundant PCO was noted when a sharp capsular bend had not formed. CONCLUSIONS: Capsular adhesion is a prerequisite of capsular-bend formation. The sharp optic edge alone does not provide a substantial barrier when a capsular bend is not formed. Bulky haptics such as those of the single-piece AcrySof and large optics may hamper capsular adhesion and bend formation.     

Anterior capsule relationship of the AcrySof intraocular lens optic and posterior capsule opacification: a prospective randomized clinical trial

OBJECTIVE: To evaluate the relationship of the anterior capsule and the AcrySof MA30BA intraocular lens (IOL) and its impact on the development of central posterior capsule opacification (PCO). DESIGN: Prospective, randomized, controlled trial. PARTICIPANTS: Two hundred two patients with senile cataracts received an AcrySof IOL between July and December 1998 at Iladevi Cataract and IOL Research Center, Ahmedabad, India. INTERVENTION: Patients were randomized prospectively to receive 1 of the 3 possibilities of anterior capsule and IOL optic relationship: group 1, total anterior capsule cover (360 degrees ) of the optic; group 2, no anterior capsule cover (360 degrees ) of the optic; group 3, partial anterior capsule cover (<360 degrees ) of the optic. After surgery, slit-lamp video photography was performed every 6 months for 3 years. Analyses of variance and chi-square tests were used to compare treatment groups. MAIN OUTCOME MEASURES: Incidence of PCO in the 3 groups. The posterior capsule was divided into 3 zones: peripheral, central 3 mm, and midperipheral (the space between the peripheral and the central zones). RESULTS: The average follow-up was 35.3 +/- 1.52 months in all the groups. At 3 years, the rate of central PCO was 6.4% in group 1, 7.1% in group 2, and 5.9% in group 3 (P = 0.9). Midperipheral PCO was present in 24.2% in group 1, 16% in group 2, and 20.6% in group 3 (P = 0.9). Peripheral PCO was seen in 100% of patients in all groups. The neodynium:yttrium-aluminum-garnet laser (Nd:YAG) posterior capsulotomy rate was 0% in all groups. CONCLUSIONS: There was no significant difference in the incidence of development of central PCO among the 3 groups. No patient experienced central PCO that required Nd:YAG capsulotomy. When using the AcrySof IOL model MA30BA, the relationship of the anterior capsule and the IOL does not seem to be a factor that relates to the development of central PCO.     

Effect of round-edged acrylic intraocular lenses on preventing posterior capsule opacification

PURPOSE: To clarify the extent to which the adhesiveness of an acrylic material influences the formation of posterior capsule opacification (PCO). SETTING: Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan. METHODS: Two types of AcrySof(R) intraocular lenses (IOLs) were prepared: round edged and tumbled. The AcrySof with round edges was implanted in 1 eye in a group of 4 rabbits and the tumbled IOL, in 1 eye in a group of 5 rabbits. In both groups, the contralateral eye received a conventional AcrySof with sharp optic edges. A histopathological examination was performed 3 weeks after surgery. RESULTS: With the round-edged AcrySof IOL, no capsular bend formed at the optic edge and abundant lens epithelial cells (LECs) migrated posteriorly. With the sharp-edged AcrySof lens, a sharp capsular bend formed and LEC migration was significantly inhibited. In eyes with a tumbled IOL, a capsular bend was created, but it was less marked than that created by the sharp-edged lens and there was slightly more LEC migration posteriorly. CONCLUSIONS: The AcrySof IOL lost its preventive effect on PCO when the optic was rounded. The effect of the AcrySof lens in preventing PCO is mainly a result of its rectangular, sharp-edged optic design. The acrylic material may play a complementary role by helping create a sharp capsular bend. Capsular bend formation is the key to the PCO preventive effect of an IOL.     

Comparison of posterior capsular opacification in heparin-surface-modified hydrophilic acrylic and hydrophobic acrylic intraocular lenses

Purpose  To compare posterior capsular opacification (PCO) in a heparin-surface-modified (HSM) hydrophilic acrylic intraocular lens (IOL) and a hydrophobic acrylic IOL. Methods  Seventy-eight patients with simple cataract were randomized to receive either the BioVue 3 HSM hydrophilic acrylic IOL (Ophthalmic Innovations International, Ontario, CA, USA) (n = 38) or the Sensar AR40e hydrophobic acrylic IOL (AMO, Santa Ana, CA, USA) (n = 40). Another 99 patients with complicated cataract received either the BioVue 3 (n = 49) or the Sensar AR40e IOL (n = 50). Twelve months after surgery, POCOman software was used to analyze digital retroillumination photographs of the PCO. Results  In the simple cataract group, the respective PCO areas, expressed as a percentage and PCO severity scores at 12 months were 6.12% and 0.081 in the BioVue 3 group and 5.91% and 0.075 in the Sensar AR40e group. There was no statistically significant difference in the PCO area or the PCO severity score between the two IOLs (P = 0.631, P = 0.495, respectively). In the complicated cataract group, the respective PCO areas and PCO severity scores were 35.80% and 0.181 in the BioVue 3 group and 27.17% and 0.110 in the Sensar AR40e group. There was no statistically significant difference between the two IOLs (P = 0.147, P = 0.162). Conclusion  There was no difference in the degree or severity of PCO between the HSM hydrophilic acrylic IOL and the hydrophobic acrylic IOL groups.     

Evaluation of posterior capsule opacification using a new posterior view method in rabbits: single-piece acrylic versus 3-piece acrylic intraocular lens

PURPOSE: To introduce a new procedure for evaluating posterior capsule opacification (PCO) in rabbit eyes and to perform a comparative study of the single-piece and 3-piece acrylic intraocular lenses (IOLs) on PCO using the new evaluation method. SETTING: Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan. METHODS: A single-piece or 3-piece acrylic IOL was implanted in 1 eye and the other in the contralateral eye of 5 rabbits. Three weeks after surgery, PCO was scored by Evaluation of Posterior Capsule Opacification (EPCO) in posterior view. Before the posterior view was photographed, the anterior capsule was removed from the whole optic area to eliminate disturbing anterior capsule opacification (ACO) for the PCO evaluation. RESULTS: Posterior capsule opacification could be well observed and viewed in the posterior view so that it could be scored by EPCO without confusion with ACO. The mean PCO score of the single-piece and 3-piece acrylic IOLs was 3.12 +/- 0.19 and 2.41 +/- 0.70, respectively (P < .05 and P = .03, respectively). CONCLUSION: The removal of ACO allowed scoring of PCO by EPCO in rabbit eyes. The single-piece acrylic IOL showed significantly more PCO than the 3-piece acrylic IOL at least 3 weeks after surgery in rabbits.     

Intraoperative explantation of two single-piece hydrophobic acrylic intraocular lenses due to surface deposits

PURPOSE: To report clinical, pathological, and laboratory analyses of two cases of single-piece hydrophobic acrylic intraocular lenses (IOLs), which presented with significant surface deposits during implantation. METHODS: The lenses were implanted with the manufacturer's recommended injector (loaded with Viscoat and Healon GV, respectively). Immediately after injection into the anterior chamber, areas on the lenses' surfaces were covered by deposits, which could not be entirely removed by irrigation/aspiration. The lenses were explanted and replaced with lenses of the same design. They underwent gross analyses, light microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy for analysis of the elemental composition of the deposits. Liquid chromatography/mass spectroscopy was also performed to identify the presence of proteins. RESULTS: The deposits on the first lens had a granular appearance, forming a homogeneous layer mostly on the posterior lens surface. Larger crystal-like deposits were present mostly on the anterior surface of the second lens. Elemental analyses of the deposits in both cases revealed the presence of peaks of sodium, chloride, phosphate, and potassium, in addition to the peaks of carbon and oxygen (normal constituents of the lens material). Only protein components normally found in the anterior chamber during surgery, such as haemoglobin and albumin, were identified. CONCLUSIONS: The results obtained suggest that the deposits in both cases may have resulted from crystallization of the ophthalmic viscosurgical device normally used during the loading of the IOLs into the cartridges.     

Effect of an acrylic intraocular lens with a sharp posterior optic edge on posterior capsule opacification

PURPOSE: To compare the posterior capsule opacification (PCO) inhibiting effect of the sharp posterior optic edge design of the Sensar OptiEdge AR40e intraocular lens (IOL) (Allergan Surgical) with that of the round-edged design of the Sensar AR40 IOL.Setting Department of Ophthalmology, University of Vienna, Vienna, Austria.METHODS: This prospective randomized patient- and examiner-masked study comprised 106 eyes of 53 patients with bilateral age-related cataract. Each patient had cataract surgery in both eyes and received an AR40 IOL in 1 eye and an AR40e IOL in the other eye. Postoperative examinations were at 1 week, 2 and 6 months, and 1 year. Digital slitlamp and digital retroillumination images of each eye were taken. The amount of PCO was assessed subjectively at the slitlamp and objectively using automated image-analysis software.RESULTS: The AR40e group had significantly less regeneratory and fibrotic PCO 1 year after surgery. The mean automated image-analysis software PCO score (scale 0 to 10) was 2.19 in the AR40 group and 1.10 in the AR40e group (P <.001). The AR40e group had less peripheral fibrotic PCO. There was no significant difference in patient-reported edge glare between the 2 IOL groups.CONCLUSIONS: The sharp-edged design of the Sensar OptiEdge AR40e IOL led to significantly less PCO than the round-edged AR40 IOL 1 year postoperatively.     

Early opacification of a single-piece hydrophobic acrylic intraocular lens after a triple procedure

We report a case in which the optic of a single-piece AcrySof acrylic (SA60AT, Alcon) intraocular lens (IOL) became opacified. A 64-year-old man had a triple procedure of vitrectomy, phacoemulsification, and IOL implantation for cataract and a dense vitreous hemorrhage in the left eye. The IOL was clear on the day after surgery, but by the third day, a dusty haze was observed on the surface due to the presence of numerous, small brown corpuscles. The IOL was removed and replaced with another SA60AT. No optic opacification occurred on the replacement IOL. Analysis of the explanted IOL indicated the presence of proteinaceous material but no calcium on the surface. Early postoperative opacification of a single-piece acrylic SA60AT IOL might occur in combined cataract and vitreous surgery, even in eyes in which the posterior capsule is intact and there are no operative complications.     

Influence of 360-degree enhanced optic edge design of a hydrophilic acrylic intraocular lens on posterior capsule opacification

PURPOSE: To compare the rate of posterior capsule opacification (PCO) with the single-piece hydrophilic acrylic foldable Rayner Centerflex 570H intraocular lens (IOL), which has a sharp optic edge design excluding the optic-haptic junction, and the Rayner C-flex 570C IOL, which has an improved 360-degree sharp edge. SETTING: Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany. METHODS: As part of a multicenter U.S. Food and Drug Administration (FDA) study, 42 patients who had implantation of a C-flex IOL in 1 eye after uneventful phacoemulsification were enrolled. Six and 12 months postoperatively, PCO was evaluated by retroillumination photographs using Evaluation of Posterior Capsule Opacification (EPCO) 2000 image-analysis software. The data were then compared with those in a matched group of patients with a Centerflex IOL who participated in a previous FDA study. RESULTS: The mean age of the patients with the C-flex IOL was 71.5 years +/- 8.2 (SD) There was a statistically significant difference in EPCO scores between the C-flex group and Centerflex group. Six months after surgery, the mean EPCO value (total IOL optic) was 0.07 +/- 0.17 in the C-flex group (n = 37) and 0.20 +/- 0.20 in the Centerflex group (n = 36) (P<.01, Wilcoxon test). By 12 months, the mean had increased to 0.16 +/- 0.20 in the C-flex group (n = 37) and 0.35 +/- 0.22 in the Centerflex group (n = 31) (P<.01, Wilcoxon test). CONCLUSIONS: The C-flex IOLs showed good functional results and significantly lower PCO formation than the earlier model Centerflex IOL. The enhanced edge of the C-flex IOL seemed to improve PCO prevention clinically.     

Evaluation of 3 modern single-piece foldable intraocular lenses: clinicopathological study of posterior capsule opacification in a rabbit model

PURPOSE: To assess the development of posterior capsule opacification (PCO) with 3 modern single-piece foldable intraocular lenses (IOLs) in a histopathological study and to compare the potential preventive effects of the IOL design and biomaterial in retarding PCO. SETTING: Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. METHODS: Thirty-one rabbit eyes were randomly operated on with phacoemulsification and implantation of 3 single-piece foldable lenses: a hydrophilic acrylic design, the Rayner Centerflex 570H (n = 11); a hydrophobic acrylic design, the Alcon AcrySof SA30AL (n = 10); and a silicone large-hole plate design, the Staar AA-4203VF (n = 10). Central PCO (CPCO), peripheral PCO (PPCO), and Soemmering's ring formation were evaluated 3 weeks after surgery using the Miyake-Apple posterior photographic technique. Histological sections of each globe were prepared to document capsular bag status and performance of IOL geometry. RESULTS: The acrylic IOLs (Centerflex and AcrySof) had lower CPCO and PPCO scores than the silicone plate IOL (P <.05). There was no significant difference in Soemmering's ring formation among the 3 models. Pathological evaluations revealed effective blockage of migrating lens epithelial cells (LECs) at the site of the truncated optic edge of the Centerflex and AcrySof IOLs, even in the presence of large amounts of retained/regenerative cortical material. CONCLUSIONS: The AcrySof IOL has a hydrophobic surface and the Centerflex a hydrophilic surface, but no correlation to these characteristics could be identified. The single-piece AcrySof optic geometry created a clear-cut barrier effect equal to that of its 3-piece predecessor. The anatomic profile of the Centerflex IOL shows the same characteristics. The optics of both acrylic lenses have square truncated edges that functionally block ingrowth of migrating LECs toward the central visual axis, leaving clear posterior capsules. The square optic edge was an appropriate geometric configuration to create a barrier effect. There was no effect of the biomaterial on PCO prevention.