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.     

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.     

Effect of four different intraocular lenses on posterior capsule opacification

AIM: To evaluate the impact of 4 different intraocular lenses (IOLs) on posterior capsule opacification (PCO) by comparing the neodymium: yttrium-aluminum-garnet (Nd:YAG) laser capsulotomy rates. METHODS: This retrospective study included 4970 eyes of 4013 cataract patients who underwent phacoemulsification and IOL implantation between January 2000 and January 2008 by the same surgeon at one clinic. Four different IOLs were assessed. The outcome parameter was the incidence of Nd:YAG laser posterior capsulotomies. RESULTS: An Nd:YAG laser posterior capsulotomy was performed in 153 (3.07%) of the 4970 eyes. The mean follow-up time was 84mo for all of the IOL groups. The percentage of eyes developing PCO was significantly greater for the acrylic hydrophilic IOLs than for the hydrophobic IOLs, although eyes with acrylic hydrophilic IOLs did not require Nd:YAG laser capsulotomy as soon as eyes with acrylic hydrophobic IOLs. There was no difference between the long-term PCO rates when 1- and 3-piece acrylic hydrophobic IOLs were compared or when IOLs made of the same material but with different haptic angles were compared. CONCLUSION: In this study, eyes with acrylic hydrophilic IOLs were more likely to develop PCO than those with acrylic hydrophobic IOLs. The lens design (1-piece versus 3-piece and varying haptic angles) did not affect the PCO rate.     

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 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.     

Quantification of posterior capsule opacification with round and sharp edge intraocular lenses

PURPOSE: To quantitatively evaluate and compare intraocular lenses (IOLs) with a round or sharp optic edge design for posterior capsule opacification (PCO). STUDY DESIGN: Prospective comparative observational case series. PARTICIPANTS/MATERIALS: Photographs from 174 eyes were analyzed for PCO at the Department of Ophthalmology, Ruprecht-Karls-University of Heidelberg, Heidelberg, Germany. MAIN OUTCOME MEASURES: Part I: 121 eyes of 121 patients were analyzed for quantification of PCO. IOLs evaluated were Corneal ACR6 (n = 21), Alcon Acrysof (n = 20), Allergan AR40 (n = 27), Pharmacia 811 one-piece polymethyl methacrylate (PMMA) IOL (n = 24), and Pharmacia 911A silicone IOL (n = 29). Mean follow-up was 14.01 +/- 2.81 months; mean patient age was 73.2 +/- 7.3 years. The morphologic PCO formation was evaluated for the entire optic and in the central 3-mm zone. Part II: In 53 eyes of 46 patients aged 73.4 +/- 10.8 years with an Alcon Acrysof IOL, PCO formation and capsulorrhexis/optic overlapping were analyzed 34.2 +/- 4 months after cataract surgery using EPCO Software. RESULTS: Part I: The PCO values of the entire optic were for Corneal ACR6, 1.93 +/- 0.62; PMMA, 0.64 +/- 0.63; AR40, 0.55 +/- 0.28; Alcon Acrysof, 0.145 +/- 0.27; and 0.161 +/- 0.181 for the Pharmacia 911A IOL (P < 0.01). The PCO values of the central 3-mm zone were for Corneal ACR6, 1.64 +/- 0.96; PMMA, 0.49 +/- 0.39; AR40, 0.22 +/- 0.32; Alcon Acrysof, 0.08 +/- 0.21; and 0.06 +/- 0.11 for the Pharmacia 911A IOL (P < 0.01). Part II: Average overlapping of capsulorrhexis and Acrysof IOL optic was 40.5% +/- 12.4%. There was a significant correlation between PCO values and overlapping (r = -0.69, P < 0.001). CONCLUSIONS: The sharp-edge IOL types (Alcon Acrysof and Pharmacia 911A silicone IOL) resulted in statistically significantly lower PCO values for analysis of the entire optic area and central 3-mm zone. There was no statistically significant difference in PCO values between the two sharp-edge optic IOLs. An overlapping of capsulorrhexis rim and the anterior IOL optic surface of more than 20% resulted in significantly lower PCO values with the Acrysof IOL.     

Incidence of posterior capsule opacification in eyes with and without posterior chamber intraocular lenses

The incidence of posterior capsule opacification after extracapsular cataract extraction was significantly lower in eyes implanted with posterior chamber intraocular lenses than in nonimplanted eyes. The number of loops fixated in the bag was significantly smaller in the eyes that became opacified than in those that did not. These findings suggest that the posterior chamber lens suppresses the two processes that lead to opacification: the development of a ring-shaped opacity at the site of contact between the anterior capsule rim and the posterior capsule and the migration of lens epithelial cells toward the center of the capsule. These suppressive effects were greater when the posterior chamber lens was fixated in the bag.     

Three-year follow-up of posterior capsule opacification with two different silicone intraocular lenses

PURPOSE: To compare posterior capsule opacification (PCO) after cataract surgery with implantation of two silicone intraocular lenses (IOLs) with different designs. METHODS: We carried out a prospective, clinical study of 116 patients randomized to standardized phacoemulsification with implantation of CeeOn Edge (n = 57) or SI40NB (n = 59) IOLs. The follow-up period was 3 years. To evaluate PCO morphologically, digital images were obtained and analysed using evaluation of posterior capsule opacification computer software (epco). The neodymium:YAG (Nd:YAG) capsulotomy rate was recorded. RESULTS: At 2 and 3 years, the eyes with SI40NB IOLs had significantly more PCO than those with the CeeOn Edge IOLs (p = 0.00014 and p = 0.002). Nine Nd:YAG capsulotomies were performed in the SI40NB group and none in the CeeOn Edge group. This difference was statistically significant (p = 0.003). In some patients a regression of PCO was noticed and confirmed using epco. Statistically less PCO was noted when the capsulorhexis rim was placed so that it covered all 360 degrees of the optic of the IOL. CONCLUSIONS: A clinically and statistically significant difference in PCO development between CeeOn Edge and SI40NB IOLs at 2 and 3 years postoperatively was found. These findings support earlier studies indicating that a sharp edge of the optic is a more important factor in IOL design than IOL material in the prevention of PCO.     

Active oxygen processing for acrylic intraocular lenses to prevent posterior capsule opacification

PURPOSE: To evaluate active oxygen processing on the surface of acrylic intraocular lenses (IOLs) to prevent secondary posterior capsule opacification (PCO). SETTING: Department of Ophthalmology, Dokkyo Medical University School of Medicine, Mibu City, Tochigi, Japan. METHODS: Acrylic IOLs were prepared, and ultraviolet (UV)/ozone (UV/O3) or argon plasma was irradiated to the surface of the IOLs. Elemental analysis (electron spectroscopy for chemical analysis [ESCA]) of the IOL surfaces was performed to confirm surface modification. Changes produced by UV/O3 or argon plasma treatment were examined for fibronectin and lens epithelial cell (LEC) adhesion. To evaluate the PCO prevention by treated IOLs, 8-week-old albino rabbits were used. The rabbit eyes randomly had phacoemulcification and implantation of 3 different IOLs: the UV/O3-treated IOLs, argon plasma-treated IOLs, and the control IOLs. After 2 weeks, the rabbits were killed and their globes were dissected and fixed using formaldehyde 10%. The PCO was observed using light microscopy (DX51, ORIMPUS) after hematoxylin and eosin staining. RESULTS: Comparison of IOL surface composition by ESCA showed an increase in nitrogen content and hydroxyl substitute and carboxyl substitute groups on surfaces of treated IOLs. The fibronectin adhesion and the LEC adhesion on the UV/O3-treated and argon plasma-treated samples were increased. In the untreated group, there was statistically significant inhibition of PCO formation in the UV/O3-treated and argon plasma-treated groups. CONCLUSION: Active oxygen processing and argon plasma irradiation on the surface of IOLs was effective in preventing secondary PCO after cataract surgery.     

Relationship between posterior capsule opacification and intraocular lens biocompatibility

The type of healing process that occurs in response to cataract surgery and intraocular lens (IOL) implantation is dependent on a complex set of variables. Their interactions determine whether or not optical clarity is restored as a result of this procedure. In this process, wound healing entails cells undergoing either epithelial-mesenchymal transition, resulting in the generation of fibroblastic cells and accumulation of extracellular matrix, or lenticular structure formation. Such desperate cellular behaviors are regulated by the localized release of different cytokines, including transforming growth factor beta and fibroblast growth factors, which can result in post-operative capsular opacification. Other factors affecting the biological and mechanical outcome of IOL implantation are its composition, surface properties and shape.     

Effect of intraocular lenses on preventing posterior capsule opacification: design versus material

PURPOSE: To compare the preventive effect of 4 types of design- and material-matched intraocular lenses (IOLs) on posterior capsule opacification (PCO). SETTING: Jinshikai Medical Foundation, Nishi Eye Hospital, Osaka, Japan. METHODS: After phacoemulsification, 1 of 2 matched IOLs in 3 groups was implanted in 1 eye and the other IOL in the contralateral eye of 4 to 6 rabbits. Three weeks postoperatively, posterior view and histopathological evaluations were performed and the capsular bending effect and amount of PCO evaluated. RESULTS: The capsular bending effect was similar between a sharp-edged acrylic IOL (Sensar 40e, AMO) and a sharp-edged silicone IOL (ClariFlex, AMO) and between the Sensar 40e IOL and a sharp-edged acrylic IOL (AcrySof, Alcon Laboratories). There was no significant difference between IOL types in the amount of PCO. The capsular bend effect was slightly better and the PCO amount slightly less with the ClariFlex IOL than with the round-edged silicone PhacoFlex II IOL (AMO). CONCLUSIONS: There was no substantial difference in PCO prevention between IOLs with sharp posterior optic edges, regardless of the IOL's material composition. The anterior edge design appeared to have no preventive effect. These results confirm that a sharp posterior optic edge is the main factor in preventing PCO.     

Clinical evaluation of posterior capsule opacification in eyes with different small-incision intraocular lenses

BACKGROUND AND OBJECTIVE: To present a new method to quantify posterior capsular opacity with an anterior eye segment image analyzer (EAS 1000, NIDEK). PATIENTS AND METHODS: This study was comprised of patients who underwent phacoemulsification intraocular lens (IOL) implantation. Three types of IOLS, acrylic, silicone, and polymethylmethacrylate (PMMA) were allocated to 30 eyes and clinically evaluated. Patients were observed for 3 years postoperatively using an anterior eye segment image analyzer (EAS1000). Opacity was determined by calculating the area of opacity from a retroillumination image. In the retroillumination mode of analysis, the measurement was limited to a 4-mm-diameter region of the pupillary zone to eliminate the influence of anterior capsular opacity. For color map analysis, the threshold level was expressed as the color tone of 0-255 CCT (computer compatible tape). The glare disability was measured to evaluate the three types of IOLs. RESULTS: The color map analysis revealed a time-related increase in the opacity level of patients receiving the PMMA IOL implant. Three years after surgery, the levels were significantly higher in the PMMA group (P < 0.01) compared to the acryl and silicone groups: acryl (17.5 +/- 3.8), silicone (18.0 +/- 6.2%), and PMMA 36.5 +/- 32.9%. CONCLUSION: Quantitative evaluation using an anterior eye segment image analyzer is effective for observing the degree of posterior capsule opacification. The color map analysis using an anterior eye segment image correlated with the visual function revealed that the time-related increase in the opacity level was significant during the third year in patients receiving PMMA IOL implantation.     

Digital retroilluminated photography to analyze posterior capsule opacification in eyes with intraocular lenses

PURPOSE: To compare the formation and rates of posterior capsule opacification (PCO) in eyes with poly(methyl methacrylate) (PMMA) versus silicone intraocular lenses (IOLs) using an in vivo objective method. SETTING: Taipei Municipal Yang-Ming Hospital, Taipei, Taiwan, Republic of China. METHODS: This prospective study comprised 40 eyes with senile cataract receiving phacoemulsification with capsular implantation of an IOL from March to April 1997. The uneventful surgeries were performed using the stop and chop method by the same surgeon. Twenty eyes received a PMMA IOL (Pharmacia 812A) and 20, a silicone IOL (AMO SI-30NB). One year later, digital retroillumination images taken with the EAS-1000 anterior segment analysis system (Nidek) were used to analyze posterior capsule transparency over the central 3.0 and 5.0 mm optic zones and evaluate the degree of PCO over the central and peripheral zones. RESULTS: Over the central 5.0 mm optic zone, mean transparency of the capsule was 87.71% +/- 11.35% (SD) in the silicone group and 79.22% +/- 21.10% in the PMMA group (P = .17). Over the central 3.0 mm optic zone, the means were 97.17% +/- 5.96% and 86.32% +/- 19.60%, respectively (P = .048). Mean opacity in the central zone was 75.18 +/- 13.22 digital opacity units (OUs) in the silicone group and 80.24 +/- 7.93 OUs in the PMMA group (P = .18). The means in the peripheral zone were 88.49 +/- 18.47 OUs and 90.35 +/- 9.98 OUs, respectively (P = .71). CONCLUSION: The posterior capsule in the silicone IOL group was more transparent than in the PMMA IOL group over the central 3.0 mm optic zone after 1 year follow-up.