Formation Of Posterior Capsule Opacification Research Articles

Role of Decorin in Posterior Capsule Opacification and Eye Lens Development.

Decorin (DCN) is involved in a variety of physiological and pathological processes. Epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs) has been proposed as a major cause for the development of posterior capsule opacification (PCO) after cataract surgery. We investigated the plausible target gene(s) that suppress PCO. The expression of Dcn was significantly upregulated in rat PCO tissues compared to that observed in the control using a microarray-based approach. LECs treated with fibroblast growth factor (FGF) 2 displayed an enhanced level of DCN expression, while LECs treated with transforming growth factor (TGF)β-2 showed a decrease in DCN expression. The expression of tropomyosin 1 (Tpm1), a marker of lens EMT increased after the addition of TGFβ-2 in human LEC; however, upregulation of Tpm1 mRNA or protein expression was reduced in human LECs overexpressing human DCN (hDCN). No phenotypic changes were observed in the lenses of 8- and 48-week-old transgenic mice for lens-specific hDCN (hDCN-Tg). Injury-induced EMT of the mouse lens, and the expression patterns of α smooth muscle actin, were attenuated in hDCN-Tg mice lenses. Overexpression of DCN inhibited the TGFβ-2-induced upregulation of Tpm1 and EMT observed during wound healing of the lens, but it did not affect mouse lens morphology until 48 weeks of age. Our findings demonstrate that DCN plays a significant role in regulating EMT formation of LECs and PCO, and suggest that for therapeutic intervention, maintenance of physiological expression of DCN is essential to attenuate EMT progression and PCO formation.

Commentary: Anterior capsule polishing: The present perspective.

Commentary: Anterior capsule polishing: The present perspective.

Retrospective Analyses of Potential Risk Factors for Posterior Capsule Opacification after Cataract Surgery.

Purpose To evaluate the potential risk factors of posterior capsule opacification (PCO) after cataract surgery. Methods Data on PCO patients diagnosed from September 2015 to May 2017 were obtained from the Department of Ophthalmology at Qingdao Municipal Hospital, Qingdao, China. The factors associated with PCO were assessed using Pearson's χ2 test for univariate analyses and logistic regression for multivariate analyses. Results Eyes (652) from 550 patients were enrolled in this study. All patients were diagnosed with PCO/non-PCO and had <3 years of follow-up after surgery. The numbers of PCO and non-PCO were 108 eyes and 544 eyes, respectively. Statistically significant associations with PCO were found for age at the time of surgery (χ2 = 78.504; p < 0.001), diabetes (χ2 = 4.829; p=0.028), immune diseases (χ2 = 4.234; p=0.004), high myopia (χ2 = 5.753; p=0.016), lens nucleus hardness (χ2 = 11.046; p=0.026), surgery type (χ2 = 11.354; p=0.001), a history of vitrectomy (χ2 = 4.212; p=0.004), ocular inflammation (χ2 = 6.01; p=0.009), and the intraocular lens (IOL) type (χ2 = 8.696; p=0.003). Multivariable data analyses using logistic regression analyses of the variables showed that age at the time of surgery <60 years, diabetes, lens nucleus hardness of III–V, extracapsular cataract extraction (ECCE), postvitrectomy, and hydrophilic IOLs were significant independent risk factors associated with PCO. Conclusions Age <60 years, diabetes, lens nucleus hardness of III–V, ECCE, postvitrectomy, and a hydrophilic IOL were significantly associated with the formation of PCO. Estimation of the incidence of and risk factors for PCO should help in patients counseling and in the design of treatment protocols to reduce or prevent its development.

Expression of Dominant Negative K6W-Ubiquitin in the Lens Epithelium via an Adenoviral Vector Delays Posterior Capsule Opacification in a Rabbit Model.

Ubiquitin is involved in cell proliferation and differentiation, and the objective of this study is to investigate the potential of dominant negative Ubiquitin (Ub) with a lysine to tryptophan mutation at the 6 position (K6W) through an adenoviral expression vector in the prevention of posterior capsule opacification (PCO) in a rabbit PCO model. Recombinant dominant negative K6W-Ub adenovirus (RAd-K6W-Ub) with green fluorescent protein (RAd-K6W-Ub/GFP) and RAd-GFP viruses (control) were generated with QBI-HEK 293A cells. New Zealand rabbits receiving lens phacoemulsification were given an intraoperative anterior chamber injection of the viruses. The images of anterior segment photography taken by a slit lamp biomicroscopy were analyzed by posterior capsule opacification manual software (POCOman) for PCO grading. The intraocular pressure (IOP) was detected with a non-contact tonometer (NCT). The expression of α-smooth muscle actin (α-SMA) was assessed by Western blotting. Cell migration ability in cultured rabbit's lens epithelial cells (LECs) was evaluated by scratch healing assay. The expression of GFP and Ub in the lens epithelium was markedly upregulated after 48 hours vector injection. Eyes injected with RAd-K6W-Ub showed a significantly lower PCO degree compared with controls. Meanwhile, higher IOP and corneal edema was observed in groups with a higher RAd-K6W-Ub virus dosage. The expression of α-SMA was down-regulated in the RAd-K6W-Ub eyes as compared to controls at the 15th day after injection. Cell migration was inhibited by RAd-K6W-Ub infection. RAd-K6W-Ub at an appropriate dosage could inhibit the proliferation of LECs and the formation of PCO in rabbit models. However, a higher dosage of Rad- K6W-Ub viral vector caused toxic effects to the surrounding tissues, such as corneal edema and high IOP.

TGF beta and fibrosis‐ironing out the wrinkles

SummaryThe fibrotic disorder Posterior Capsule Opacification (PCO) is the leading secondary ocular complication following cataract surgery. PCO causes a significant loss of vision for approximately 10–30% of patients, 2–5 years post cataract removal. The formation of PCO requires additional surgical treatment, presenting an additional and substantial burden on health care providers and affects the overall well‐being of cataract patients. Fibrotic disorders affect many organs of the body and are associated with hyperproliferation, cell transdifferentiation, matrix modification and contraction. Identifying the major control of these features is essential to our understanding of PCO development. Transforming growth factor beta (TGFβ) has long been implicated in fibrotic disorders and is commonly defined as the “master switch” of fibrosis. However the actions governed by TGFβ can be complex and diverse involving multiple signalling pathways and cross‐talk between many signalling cascades. Significant understanding of the key pathways regulating TGFβ induced modifications in PCO has been identified using human cell and tissue culture models. These important findings and how they may be used as therapeutic targets will be presented.

Square-edge intraocular lenses and epithelial lens cell proliferation: implications on posterior capsule opacification in an in vitro model.

BackgroundTo evaluate lens epithelial cell (LEC) proliferation with two different designs (one-piece or three-piece) of hydrophobic acrylic IOLs with 360° square optic edge using an in vitro culture model of posterior capsule opacification (PCO).MethodsThis experimental study was conducted at the Department of NEUROFARBA, Section of Pharmacology, University of Florence, Italy. Human LECs were seeded and cultured in transwell cell culture inserts coated with a type-IV collagen membrane on which an IOL (one-piece Tecnis-1 or three-piece AR40E, Abbott Medical Optics Inc.) had been previously placed. As control, cells were plated on the insert membrane without an IOL. At day six (cells confluent in controls) IOLs were removed and cell counting, viability and cell density under and outside the IOLs were evaluated.ResultsNo statistically significant difference in the number of cells (p > 0.05) between inserts with the one-piece and three-piece IOLs was found. Cell density in the area under each IOL was significantly lower than in the area outside of it (p < 0.05), or in the control insert. (p < 0.05). Cell density under the single-piece IOL was not significantly different from that under the three-piece IOL (p > 0.05).ConclusionsA 360° sharp-edge played a crucial role in avoiding LEC migration under the IOL and preventing the formation of PCO after cataract surgery. Long term clinical evaluation is necessary to estimate functional results.

Retinal Straylight before and after Implantation of the Bag in the Lens IOL

To quantify the changes in retinal straylight that occur after implantation of the Bag in the Lens (BIL) IOL, which by design avoids the formation of posterior capsule opacification or any influence of the posterior lens capsule. This prospective study included 81 eyes of 53 cataract patients planned for surgery with the BIL. Preoperatively and 6 months postoperatively their straylight level was determined using the compensation comparison method. After implantation of the BIL straylight significantly improved from 1.59 ± 0.26 preoperatively to 1.19 ± 0.21 log units postoperatively (paired t-test, P < 0.001). Postoperative straylight was within age-normal levels in 56.1% of the eyes and went below age-normal values in 40.2% of the eyes. Average postoperative straylight remained 0.27 log units (or 1.87×) above the age-independent base straylight value of 0.931 + 0.200. Postoperatively straylight was not significantly correlated with age (r(2) = 0.001), but it was significantly correlated with a regression model that combines both age and axial length (r(2) = 0.199). Retinal straylight after implantation of the BIL is comparable to what has been published for the early follow-up of other IOL types, suggesting that a clear posterior lens capsule does not seem to add to straylight. However, for all IOL types average postoperative straylight remains above the expected base level, possible due to nonlenticular age-related parameters or to the physiological response of the ocular tissues to the surgical act. This should be examined in further detail in future studies.

Effect of tTG inhibitor on the expression of FN and Col-IV induced by TGF-β2 in human lens epithelial cells

BackgroundOur previous research and other reports disclosed that the expression of tissue transglutaminase(tTG)in lens epithelial cells(LECs) of patients with cataract is enhanced,indicating tTG is related to formation of posterior capsule opacification(PCO).ObjectivePresent study is to observe the effect of tTG specific inhibitor monodansyl-cadaverineon(MDC) on the expression of fibronectin(FN) and collagen Ⅳ(Col-Ⅳ) induced by TGF-β_2 in human LECs.MethodsHLE-B3 was cultured in vitro in DMEM containing 10% fetal bovine serum and then were divided into 5 groups.The free-serum culture was used as normal control group.Free-serum culture containing 10μg/L TGF-β_2 was utilized as treatment group.10μg/L TGF-β_2 plused 100μmol/L,200μmol/L and 400μmol/L MDC respectively in different concentrations as MDC-treatment group.Semiquantitative RT-PCR was used to assay the expression of tTG,FN and Col-Ⅳ in HLE-B3.A(tTG/β-actin),A(FN/β-actin) and A(Col-Ⅳ/β-actin) was calculated separately as the detecting indexes.ResultstTG,FN and Col-Ⅳ were positively expressed in cultured HLE-B3.The expression levels of tTG,FN and Col-Ⅳ in HLE-B3 were remarkably increased in the group with 10μg/L TGF-β_2 compared with normal control group(t=33.95,P<0.01;t=38.24,P<0.01;t=13.48,P<0.01).The expression levels of FN and Col-Ⅳ were gradually declined in 100,200 and 400μmol/L MDC groups in comparison with TGF-β_2 treatment(P<0.01).The significant differences were also found in the expressions of FN and Col-Ⅳ in HLE-B3 among 100,200 and 400μmol/L MDC groups(P<0.01).ConclusionMDC inhibits the expression of FN and Col-Ⅳ induced by TGF-β_2 in human LECs at a concentration-dependent manner.tTG may be involved in the formation of posterior capsule opacification through up-regulating the expressions of FN and Col-Ⅳ in human LECs. Key words: lens epithelial cells; tissue transglutaminase; extracellular matrix,posterior capsule opacification

The effects of connective tissue growth factor on bovine lens epithelial cells in vitro

Objective This study was to observe the effects of connective tissue growth factor(CTGF) on migration and transdifferentiation of bovine lens epithelial cells(BLECs). MethodsThe culture and identification of BLECs adopted the method of Hu(reference 1).The 2-3 passages of BLECs were collected and used in this experiment at the concentration of 1×10~6 cells/hole.The free-serum DMEM containing 0.1 ng/L,0.5 ng/L,1.0 ng/L of CTGF was added into medium for 24 hours in different experimental group respectively,and only equal volume of free-serum DMEM was added in control group.Expression of α-smooth muscle actin(α-SMA) mRNA and protein in the BLECs were examined by semiquantitative RT-PCR and Western blot,respectively.The transwell inserts were used to evaluate the migration ability of BLECs. ResultsThe expression of α-SMA mRNA in cultrued BLECs was gradually increased in different concentrations of CTGF groups.Compared with control group,the expression of α-SMA mRNA in experimental group was significantly enhanced (F=66.56,P＜0.01).The expression of α-SMA protein followed the same pattern(F=65.43,P＜0.01).The migration ability of BLECs was obviously elevated after CTGF stimulation under the light microscope.The migration rate of BLECs was considerably increased in experimental group compared with blank control group (t=51.7,P＜0.01).ConclusionCTGF promotes the migration and transdifferentiation of BLECs at a dose-dependent manner in vitro.CTGF plays an important role in the formation of posterior capsule opacification. Key words: connective tissue growth factor; lens epithelial cells; migration; smooth muscle actin; cataract

Selenium functionalized intraocular lenses inhibit posterior capsule opacification in an ex vivo canine lens capsular bag assay

The purpose of this study was to determine the inhibitory effect of selenocystamine coated intraocular lenses (IOLs) on the formation of posterior capsule opacification (PCO) in an ex vivo canine lens capsular bag assay. Selenocystamine was covalently bound to the surface of poly(2-hydroxyethyl methacrylate) (poly(HEMA)) discs. Three groups of canine lens capsules (6 coated IOLs (SeIOLs), 7 non-coated control IOLs and 8 empty capsules) were cultured for 10 days. During the culture period PCO was scored based on visual inspection of the capsules using phase contrast microscopy. On day 10 all the capsules were prepared for light microscopic examination and lens epithelial cells (LECs) were quantified. Proliferating cell nuclear antigen (PCNA), α-smooth muscle actin (α-SMA) and cleaved caspase-3 were examined by immunohistochemistry. Additionally, cell viability assays were performed on LECs cultured in tissue culture medium pre-incubated with either a SeIOL or control IOL. The viability assays demonstrated that no detectable cytotoxic leachables were associated with the functionalized IOLs. The central posterior capsule was free of cells underneath all SeIOLs, although large numbers of LECs populated the capsular periphery. Apoptotic cells were observed underneath the periphery of some SeIOLs. Both the PCO scores and LEC counts of SeIOL containing capsules were significantly lower than those of control group capsules (p < 0.01 and p = 0.0004, respectively).The use of selenium functionalized IOLs resulted in a significant reduction of PCO in this ex vivo model. Binding of selenocystamine to a foldable IOL may provide an effective method to prevent population of the central posterior capsule with LECs.

A long-term follow-up study of different irrigation/aspiration techniques on formation of posterior capsule opacification

Background: This study was designed to determine the effect of 2 different irrigation/aspiration techniques on the formation of posterior capsule opacification (PCO) after cataract surgery in which CeeON Edge 911A (Pharmacia, Sweden) sharp-edged silicone lenses were implanted. Methods: In this prospective study, 60 eyes from 39 patients, average age 65 (range: 46–85) years, were analyzed. Lens extraction was performed by phacoemulsification, and CeeON Edge 911A intraocular lenses were implanted. Two different irrigation/aspiration techniques were used in which the cortex of 32 eyes was removed by coaxial irrigation/aspiration (this group was designated group I) and the cortex of 28 eyes was removed by bimanual irrigation/aspiration (this group was designated group II). Secondary cataract formation and visual acuity were evaluated and compared in both groups. Results: The average follow-up time was 44 (SD 11) months. In group I, secondary cataract formation causing 2 lines of decrease on visual acuity was observed in 1 eye 8 months after the operation. The secondary cataract developed in the form of cortex migration. This patient was treated with laser (Neodymium: Yttrium Aluminum Garnet [Carl Zeiss Meditech, Germany]) capsulotomy at the time of detection. Best corrected visual acuity for all eyes was 0.5 and higher; postoperative refractive error ranged between +1.0 and −2.0 diopters. Interpretation: Although CeeON Edge 911A silicone lenses with sharp edge prevent formation of PCO very effectively, in 1 eye in the coaxial irrigation/aspiration group, 2 lines of decrease on visual acuity were observed due to PCO. However, we did not find any significant difference between the 2 irrigation/aspiration techniques with respect to PCO formation. In terms of complete removal of the cortical material, the bimanual irrigation/aspiration technique was found to be superior to the coaxial irrigation/aspiration technique because of the better accessibility to all areas of the capsular bag.

Contact inhibition of migrating lens epithelial cells at the capsular bend created by a sharp-edged intraocular lens after cataract surgery

To investigate whether the lens epithelial cells (LECs) at the capsular bend created by a sharp-edged intraocular lens (IOL) are in the G(0) phase of the cell cycle. Nishi Eye Hospital, Osaka, Japan. A CeeOn Edge silicone IOL (AMO) with sharp edges was implanted in 1 eye and a PhacoFlex II silicone IOL (AMO) with rounded edges in the contralateral eye after standard cataract surgery in 6 rabbits. Immunohistochemical staining for the Ki-67 antibody was performed 1 day, 3, 4, and 7 weeks after surgery. In eyes with the sharp-edged IOL, LECs with thin, elongated nuclei accumulated at, but did not extend beyond, the capsular bend and stained negative for the Ki-67 antibody, indicating that they were in the G(0) phase of the cell cycle. In contrast, in the eye with the round-edged IOL, continuous migration of a predominantly monolayer of LECs over the IOL and onto the posterior capsule occurred. These cells were Ki-67 positive, indicating that they were proliferating. Lens epithelial cells at the capsular bend of sharp-edged IOLs were in the G(0) phase of the cell cycle, indicating that they were contact inhibited. These findings support the theory the sharp posterior optic edge of the IOL inhibits LEC migration, reducing formation of posterior capsule opacification. Whether these LECs can reactivate when the capsular bend is eliminated by later formation of a Soemmerring's ring requires further studies.

Posterior capsule opacification after phacoemulsification in patients with postoperative steroidal and nonsteroidal treatment

Purpose: To evaluate the effect of dexamethasone, diclofenac, and a placebo given for 3 weeks after phacoemulsification and intraocular lens (IOL) implantation on the formation of posterior capsule opacification (PCO). Setting: St. Erik's Eye Hospital, Stockholm, Sweden. Methods: In a 2-year prospective randomized double-blind study, a laser flare meter was used to measure aqueous flare intensity preoperatively and 3 days, 2 weeks, and 2 years after phacoemulsification and IOL implantation. Posterior capsule opacification was evaluated 2 years postoperatively using retroillumination images taken with a Scheimpflug camera. The Evaluation of Posterior Capsule Opacification system was used to score the areas of PCO density. Results: The median rate of PCO 2 years after phacoemulsification was 0.72 (range 0.32 to 1.57) in the dexamethasone group, 0.78 (range 0.19 to 2.14) in the diclofenac group, and 0.70 (range 0.35 to 1.70) in the placebo group. The differences were not statistically significant ( P>.05; Kruskal-Wallis analysis of variance, multiple comparisons). The rate of neodymium:YAG laser posterior capsulotomy during the 2 years after surgery was not statistically different between groups ( P>.05, chi-square test). There was no correlation (Spearman rank coefficient) between laser flare measurements and PCO formation in any group during the study ( P>.05). Conclusion: Topical instillation of diclofenac, dexamethasone, or a placebo in the immediate period after phacoemulsification and IOL implantation did not seem to influence the formation of PCO 2 years after cataract surgery.

Analysis of cytoskeletal proteins in posterior capsule opacification after implantation of acrylic and hydrogel intraocular lenses

Purpose: To analyze selected lens cytoskeletal proteins in posterior capsule opacification (PCO) 2 weeks after intraocular lens (IOL) implantation in rabbits. Setting: Department of Ophthalmology, Dokkyo University School of Medicine, Tochigi, Japan. Method: Eight 10-week-old albino rabbits were prepared and anesthetized for phacoemulsification and aspiration of the crystalline lens and implantation of an acrylic or a hydrogel IOL. Two weeks postoperatively, the rabbits were killed and the IOLs removed for immunohistochemistry. Deparaffinized tissue sections were processed with antibodies against α-smooth muscle actin (α-SMA) and β-crystallin to observe the types of PCO with the 2 IOL types. The proteins in the PCO tissue and the normal lens were homogenized, centrifuged, and analyzed using SDS-polyacrylamide gel electrophoresis (SDS-PAGE) densitometric analysis and Western immunoblotting for actin and vimentin. Results: Immunohistochemistry demonstrated a fibroblastic cell type expressing α-SMA and partial regeneration of epithelial cells, resulting in a lenticular structure that stained irregularly for β-crystallin. The immunoreactivity of fibroblast-like cells to β-crystallin appeared weaker than that of the regenerated lenticular structure. SDS-PAGE showed variability in the content of cytoskeletal proteins in the insoluble fractions of the PCO. Degradation of the cytoskeletal components was greater with the acrylic IOL than with the hydrogel IOL. Conclusion: Cytoskeletal proteins expressed during the formation of PCO and IOL implantation may have potential as therapeutic target proteins to improve the biocompatibility of IOLs.

Implantation of a single-piece, hydrophilic, acrylic, minus-power foldable posterior chamber intraocular lens in a rabbit model: Clinicopathologic study of posterior capsule opacification

Purpose To compare the extent of posterior capsule opacification (PCO) after implantation of a standard-power biconvex Centerflex® intraocular lens (IOL) and a newly introduced biconcave high-minus-power Centerflex design in rabbit eyes. Setting The Center for Research on Ocular Therapeutics and Biodevices, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, and the David J. Apple, MD, Laboratories for Ophthalmic Devices Research, John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, Utah, USA. Methods Twelve rabbits had phacoemulsification and implantation of 2 foldable single-piece hydrophilic acrylic Centerflex posterior chamber IOLs. The right eyes received a standard-power (+21.00 diopters [D]) biconvex-optic lens and the left eyes, a minus-power (–7.00 D) biconcave-optic IOL. Formation of PCO was evaluated 3 weeks after surgery using the Miyake-Apple posterior photography technique. Histological sections from each globe were prepared to analyze capsular bag status and assess postsurgical intracapsular lens epithelial cell (LEC) proliferation, especially ingrowth of LECs across the visual axis. The data were analyzed using the Kruskal-Wallis 1-way analysis of variance for nonparametric measurements and the Mann-Whitney rank sum test. Results There was no significant difference in Soemmering's ring formation between the 2 IOL models. The biconcave minus-power IOL showed significantly lower central and peripheral PCO scores than the biconvex standard-power lens ( P<.05). Pathological evaluations revealed that the effective site of blockage of LECs was at the truncated optic edge of both lenses, even in the presence of retained and/or regenerative cortical material. Conclusions This study confirms the efficacy of a truncated IOL optic in helping reduce the incidence of PCO. Both IOL designs have optic geometries that create clear-cut barrier effects. However, the biconcave minus-power IOL, which has a thicker, square, truncated optic edge with a ridge that encircles the periphery of the optic for 360 degrees, appears to have an enhanced barrier effect, especially at the optic–haptic junction. This further minimizes the ingrowth of migrating LECs toward the visual axis.

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® 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.

Posterior capsule opacification and neodymium:YAG capsulotomy with heparin-surface-modified intraocular lenses

Purpose: To compare the effect of heparin-surface-modified (HSM) and conventional unmodified poly(methyl methacrylate) (PMMA) intraocular lenses (IOLs) on the formation of posterior capsule opacification (PCO).Setting: Department of Ophthalmology, Vejle Hospital, Denmark.Methods: This prospective, randomized, double-blind study comprised 250 eyes of 246 patients who had uneventful extracapsular cataract extraction in otherwise healthy eyes with implantation of a biconvex IOL or a convex-piano lens with a continuous laser ridge. Patients were examined once a year for 3 years, at which time the degree of PCO was recorded. A neodymium:YAG laser capsulotomy was performed if certain criteria were met.Results: The incidence of PCO was statistically significantly higher in eyes with an HSM convex-piano laser-ridge IOL than in those with an unmodified convex-piano lens (P < .005). There were no significant differences between any other groups.Conclusion: The incidence of PCO was higher in eyes with an HSM convex-piano IOL with a laser ridge.