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

Factors Affecting Posterior Capsule Opacification in the Development of Intraocular Lens Materials

Posterior capsule opacification (PCO) is the most common complication arising from the corrective surgery used to treat cataract patients. PCO arises when lens epithelial cells (LEC) residing in the capsular bag post-surgery undergo hyper-proliferation and transdifferentiation into myofibroblasts, migrating from the posterior capsule over the visual axis of the newly implanted intraocular lens (IOL). The developmental pathways underlying PCO are yet to be fully understood and the current literature is contradictory regarding the impact of the recognised risk factors of PCO. The aim of this review is firstly to collate the known biochemical pathways that lead to PCO development, providing an up-to-date chronological overview from surgery to established PCO formation. Secondly, the risk factors of PCO are evaluated, focussing on the impact of IOLs’ properties. Finally, the latest experimental model designs used in PCO research are discussed to demonstrate the ongoing development of clinical PCO models, the efficacy of newly developed IOL technology, and potential therapeutic interventions. This review will contribute to current PCO literature by presenting an updated overview of the known developmental pathways of PCO, an evaluation of the impact of the risk factors underlying its development, and the latest experimental models used to investigate PCO. Furthermore, the review should provide developmental routes for research into the investigation of potential therapeutic interventions and improvements in IOL design in the aid of preventing PCO for new and existing patients.

Incidence of posterior capsule opacification following phacoemulsification in patients with uveitis

PURPOSE:

The purpose of this study was to evaluate the incidence of posterior capsule opacification (PCO) in patients with inactive uveitis who underwent phacoemulsification with acrylic hydrophobic intraocular lens.

METHODS:

Thus was a retrospective review of 25 consecutive patients (31 eyes) with uveitis who underwent phacoemulsification. A group of 100 patients (140 eyes) without uveitis served as historical controls.

RESULTS:

In patients with uveitis, PCO occurred in 11 eyes (35.5%), 6 (19%) of which were visually significant and required treatment with neodymium-doped yttrium aluminum garnet (Nd: YAG) laser. In the control group, PCO developed in 17 (12%) eyes which required treatment with Nd: YAG laser. The incidence of PCO was significantly higher in uveitis patients compared to the control group (P = 0.001), but the incidence of visually significant PCO requiring laser capsulotomy was not statistically significant (P = 0.3).

CONCLUSION:

The incidence of PCO in patients with uveitis was significantly higher than those without uveitis, but the need for Nd: YAG laser capsulotomy for visually significant PCO was not statistically significant.

A Review of Complicated Cataract in Retinitis Pigmentosa: Pathogenesis and Cataract Surgery

Retinitis pigmentosa (RP) is a set of inherited retinal degenerative diseases that affect photoreceptor and retinal pigment epithelial cells (RPEs), possibly associated with some ocular complications, including cataract. The complicated cataract formation is most likely the result of RP-related inflammation response, and the most common morphology category is posterior subcapsular cataract (PSC). Despite the absence of curative pharmacologic treatment, phacoemulsification with intraocular lens implantation to deal with opacification in the lens is preferred due to the considerable visual outcomes. However, the incidence of intraocular and postoperative complications is higher in RP patients than those without, including intraoperative phototoxic retinal damage, posterior capsular opacification (PCO), capsular contraction syndrome (CCS), pseudophakic cystoid macular edema (PCME), increased postoperative intraocular pressure (IOP), and intraocular lens (IOL) dislocation. Hence, it needs much attention to surgery progress and close follow-up. In this review, we discuss the current understanding of RP patients with complicated cataracts from morphology to potential pathogenesis to cataract surgical procedure and provide a concise description and the recommended management of related surgery complications to broaden the knowledge and lower the latent risks to yield better clinical outcomes.

Measurement of Force Required for Anterior Displacement of Intraocular Lenses and Its Defining Parameters

Intraocular stability during or after cataract and glaucoma filtration surgeries and vitreous surgery with a gas/silicone oil tamponade might differ among intraocular lenses (IOLs). We used six different one-piece IOL models and measured the force that displaced the IOLs from the vitreous cavity to anterior chamber as a measure of stability against the pressure gradient between the anterior and posterior IOL surfaces. We measured IOL hardness, haptics junction area, and posterior IOL bulge to identify what determines the IOL displacement force. The KOWA YP2.2 IOL (1.231 mN) required significantly greater force than the HOYA XY1 (0.416 mN, p = 0.0004), HOYA 255 (0.409 mN, p = 0.0003), Alcon SN60WF (0.507 mN, p = 0.0010), and Nidek NS60YG (0.778 mN, p = 0.0186) IOLs; J&J ZCB00V IOL (1.029 mN) required greater force than the HOYA XY1 (p = 0.0032) and HOYA 255 (p = 0.0029) IOLs; the Nidek NS60YG IOL required greater force than the HOYA 255 (p = 0.0468) IOL. The haptics junction area was correlated positively with the IOL displacement force (r = 0.8536, p = 0.0306); the correlations of the other parameters were non-significant. After adjusting for any confounding effects, the haptics junction area was correlated significantly with the IOL displacement force (p = 0.0394); the IOL hardness (p = 0.0573) and posterior IOL bulge (p = 0.0938) were not. The forces that displace IOLs anteriorly differed among one-piece soft-acrylic IOLs, and the optics/haptics junction area was the major force determinant.

Long-term outcome of cataract surgery: 20-year results from a population-based prospective study

PURPOSE

To report the longitudinal visual functional outcome after cataract surgery over 20 years.

SETTING

Eye clinic, Norrlands University Hospital, Sweden.

DESIGN

Prospective population-based cohort study.

METHODS

One hundred fourteen patients (86% of survivors) who had cataract surgery during a 1-year period (1997 to 1998) answered the same Visual Function Index-14 questionnaire (VF-14) preoperatively, 2 to 4 months postoperatively, and at 5, 10, 15, and 20 years after surgery. Most patients (100 [88%] of 114; 75% of survivors) also had a routine ocular examination, including corrected distance visual acuity (CDVA).

RESULTS

The mean age of the114 patients in the study was 60.6 years (range 36 to 80 years) at the time of surgery. Twenty years after surgery, the median CDVA in the operated eye had deteriorated from Snellen acuity 20/20 (logarithm of the minimum angle of resolution [logMAR] 0.0) postoperatively to 20/23 (logMAR 0.07) (P = .001). Patients aged 70 years or older at surgery had the largest loss of CDVA at 20 years compared with younger patients. At 20 years, 63 (55%) of the 114 patients had no deterioration in subjective visual function and most patients (82 [72%]) had 10 points decline or less. Patients who were older at surgery had a more pronounced decline in VF-14 total score over 20 years (P = .002). Fifty-six (58%) of 96 patients had never been treated for posterior capsule opacification.

CONCLUSIONS

This prospective 20-year follow-up study provided estimates of longitudinal visual results. Cataract surgery also offered excellent long-term visual rehabilitation for the majority, especially younger patients, after 20 years, with a low requirement for Nd:YAG laser capsulotomy. The results in this study are of value for counseling younger patients with cataract and patients considering refractive lens surgery.

Intraindividual comparison of capsule behavior of 2 hydrophobic acrylic intraocular lenses during a 5-year follow-up

PURPOSE

To evaluate and compare the 5-year postoperative anterior (ACO) and posterior capsule opacification (PCO), the occurrence of glistenings, and the level of anterior capsule retraction after implantation of 2 designs of 1-piece hydrophobic acrylic IOLs.

SETTING

Hospital St. John, Vienna, Austria.

DESIGN

Randomized controlled prospective case series.

METHODS

Patients had an Acrysof SA60AT IOL (Group A) implanted in 1 eye and a Tecnis ZCB00 IOL (Group B) implanted in the fellow eye. At 1, 3, and 5 years, the PCO level was evaluated with the Evaluation of Posterior Capsule Opacification software. The level of ACO and capsule retraction was graded subjectively. Glistenings were scored as present or not present.

RESULTS

Fifty eyes of 25 patients were evaluated after 5 years. No significant differences in PCO scores were found between the 2 groups at all follow-up visits (1 year: 0.06 ± 0.12 [SD] versus 0.07 ± 0.13, P = .35; 3 years: 0.23 ± 0.36 versus 0.22 ± 0.32, P = .66; 5 years: 0.36 ± 0.41 versus 0.36 ± 0.54, P = .98). A significant increase in PCO score was found between 3 and 5 years (P < .01). Anterior capsule opacification was present in Group A and Group B in 18.0% and 2.7% of eyes (P = .03), in 92.0% and 24.0% of eyes, and in 100% and 52% of eyes (P < .01) at 1, 3, and 5 years, respectively. Glistenings (5 years 100%) were observed in Group A.

CONCLUSION

Both IOLs had a comparable PCO rate 5 years after surgery, although more ACO and retraction as well as glistenings were observed in Group A.

Five-Year Cumulative Incidence and Risk Factors of Nd:YAG Capsulotomy in 10 044 Hydrophobic Acrylic 1-Piece and 3-Piece Intraocular Lenses

PURPOSE

To evaluate the 5-year cumulative incidence and risk factors of Nd:YAG capsulotomy between hydrophobic acrylic intraocular lenses (IOLs).

DESIGN

A retrospective cohort study.

METHODS

A review of the registry of operations between the years 2007 and 2016 was carried out at the Ophthalmology Unit of Kymenlaakso Central Hospital, Kotka, Finland. A total of 10 044 eyes having cataract surgery and in-the-bag implantation of ZCB00 (Abbott Medical Optics Johnson & Johnson Vision, Inc, Abbott Park, Illinois, USA), SN60WF (Alcon Laboratories, Inc, Fort Worth, Texas, USA), or ZA9003 (Abbott Medical Optics Johnson & Johnson Vision, Inc) IOLs were included in the study. The cumulative incidence of Nd:YAG capsulotomy was estimated with competing risks methodology. Competing risks regression modeling was used to evaluate potential risk factors, including the patient's age, sex, type of IOL, dioptric power of IOL, and operating surgeon's seniority.

RESULTS

The 5-year cumulative incidence of Nd:YAG capsulotomy after cataract surgery was 13.2% (95% confidence interval [CI] 12.5%-14.0%) for all eyes and 18.1% (16.5%-20.0%), 11.5% (10.5%-12.6%), and 9.6% (8.2%-11.4%) for ZCB00, SN60WF, and ZA9003 IOLs, respectively. Implantation of SN60WF and ZA9003 IOLs was associated with a 38% and 47% subhazard reduction (SHR), respectively, compared to ZCB00, after accounting for other predictors (SHR = 0.62; 95% CI 0.54-0.71; P < .001 and SHR = 0.53; 95% CI 0.43-0.64; P < .001). Increased risk of Nd:YAG capsulotomy was associated with eyes of patients aged younger than 60 years, female sex, and eyes implanted with an IOL of <22.5 diopters power.

CONCLUSION

Real-world evidence suggests that the cumulative incidence of Nd:YAG capsulotomy is significantly lower in eyes receiving SN60WF or ZA9003 IOLs compared to ZCB00.

Biomaterial Influence on Intraocular Lens Performance: An Overview

There is strong evidence that the IOL material is the factor having the greatest impact on posterior capsule opacification (PCO), anterior capsule opacification (ACO) development, and glistening formation after cataract surgery, even though there are other IOL features—such as haptic material and design and edge and optic design—that also have some influence. We reviewed the published literature describing the adverse events that are mainly related to the intraocular lens (IOL) material, such as PCO, ACO, and the subsequent capsule contraction, as well as glistening formation. The adverse events presented in this overview are the most common ones in clinical practice, and therefore, they are generally included in the clinical protocols for IOL evaluation.

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.

Comparison of Nd: YAG capsulotomy rate between 1-piece and 3-piece acrylic intraocular lenses: A STROBE-compliant article

The aim of the study is to compare Nd:YAG capsulotomy rate between acrylic 1- and 3-piece intraocular lenses. Among 924 eyes of 762 patients who received cataract surgery, we selected the 303 patients (404 eyes) implanted with an SN60WF 1-piece intraocular lens (Alcon, Fort Worth, TX) or a YA-60BBR 3-piece intraocular lens (Hoya Co., Tokyo, Japan). For intraindividual comparison, we enrolled the 17 patients implanted with an SN60WF in 1 eye and a YA-60BBR in the contralateral eye. We compared Nd:YAG capsulotomy rate between acrylic 1- and 3-piece intraocular lenses 24 months after the operation. Of the 404 eyes in this study, Nd:YAG capsulotomy was performed in 20 of 268 eyes (7.5%) in the SN60WF 1-piece intraocular lens group and 24 of 136 eyes (17.6%) in the YA-60BBR 3-piece intraocular lens group; the difference was statistically significant (P = .002). Among the 17 patients (34 eyes) who were implanted with 2 different inraocular lenses, Nd:YAG capsulotomy was performed in only 2 eyes (12%) in the SN60WF group and 9 eyes (53%) in the YA-60BBR group; the difference was statistically significant (P = .020).The authors found a significantly greater incidence of Nd:YAG capsulotomy in eyes who received 3-piece lenses compared with those who received 1-piece lenses.

Comparisons of the in-the-bag stabilities of single-piece and three-piece intraocular lenses for age-related cataract patients: a randomized controlled trial

Background

To compare the in-the-bag stability and visual function of single-piece intraocular lenses (IOLs) and three-piece IOLs.

Methods

A total of 65 patients with age-related cataracts (80 eyes) were enrolled and randomly assigned to receive in-the-bag implantation of either a single-piece IOL (40 eyes) or a three-piece IOL (40 eyes). Follow-up visits were conducted at 1 week, 1 month and 3 months postoperatively. Visual acuity, refraction and total aberration were examined. IOL position stability (including axial movement, decentration and tilt) was measured using a Scheimpflug imaging system.

Results

At the 3-month follow-up visit, single-piece IOLs did not exhibit significant axial movement (0.07 ± 0.30 mm, p = 0.13) compared with their axial position at 1 week postoperatively, whereas three-piece IOLs displayed forward axial movement of −0.22 ± 0.23 mm (p < 0.0001). The mean manifest spherical equivalence (SE) of eyes with single-piece IOL was 0.15 ± 0.18D, whereas in eyes with three-piece IOLs, the mean manifest SE was −0.34 ± 0.15D (p < 0.001). There was no statistically significant difference in IOL decentration, tilt, uncorrected visual acuity, best-corrected visual acuity or total spherical aberration between the two groups.

Conclusions

Three months after implantation, single-piece IOLs exhibit better axial stability and more stable refractive outcome than three-piece IOLs, but both IOLs perform equally well in terms of decentration, tilt, visual acuity and total aberration.

Trial registration

ClinicalTrial.gov, NCT02609997, 11/18/2015, retrospectively registered.

Electronic supplementary material

The online version of this article (doi:10.1186/s12886-016-0283-4) contains supplementary material, which is available to authorized users.

Customized Clinical Practice Guidelines for Management of Adult Cataract in Iran

Purpose:

To customize clinical practice guidelines (CPGs) for cataract management in the Iranian population.

Methods:

First, four CPGs (American Academy of Ophthalmology 2006 and 2011, Royal College of Ophthalmologists 2010, and Canadian Ophthalmological Society 2008) were selected from a number of available CPGs in the literature for cataract management. All recommendations of these guidelines, together with their references, were studied. Each recommendation was summarized in 4 tables. The first table showed the recommendation itself in clinical question components format along with its level of evidence. The second table contained structured abstracts of supporting articles related to the clinical question with their levels of evidence. The third table included the customized recommendation of the internal group respecting its clinical advantage, cost, and complications. In the fourth table, the internal group their recommendations from 1 to 9 based on the customizing capability of the recommendation (applicability, acceptability, external validity). Finally, customized recommendations were sent one month prior to a consensus session to faculty members of all universities across the country asking for their comments on recommendations.

Results:

The agreed recommendations were accepted as conclusive while those with no agreement were discussed at the consensus session. Finally, all customized recommendations were codified as 80 recommendations along with their sources and levels of evidence for the Iranian population.

Conclusion:

Customization of CPGs for management of adult cataract for the Iranian population seems to be useful for standardization of referral, diagnosis and treatment of patients.

The effect of single-piece hydrophobic acrylic intraocular lenses on the development of posterior capsule opacification

PURPOSE

To evaluate the long-term effect of a single-piece hydrophobic acrylic intraocular lens (IOL), AcrySof SN60AT (Alcon Laboratories, Fort Worth, Texas, USA), on the development of posterior capsule opacification (PCO) 5 years postoperatively.

DESIGN

Prospective, observational, consecutive, case series.

METHODS

setting: Iladevi Cataract and IOL Research Center, Ahmedabad, India.

STUDY POPULATION

Three hundred and ninety eyes with uncomplicated age-related cataract were included. Patients with diabetes mellitus, glaucoma, high myopia, pseudoexfoliation, traumatic cataract, subluxated cataract, previous ocular surgeries, and allergy to dilating drops were excluded. intervention procedures: Digital retroillumination photographic documentation was performed and analyzed for PCO using Evaluation of Posterior Capsule Opacification software. The scores and areas were calculated.

MAIN OUTCOME MEASURES

PCO development and the influence of the anterior capsule cover (total on and part on) on the IOL optic was studied within the capsulorrhexis margin and the central 3.0 mm optic area.

RESULTS

There was a significant increase in PCO up to 3 years. No significant change in PCO was observed between 3 and 5 years within the capsulorrhexis margin and central 3.0 mm optic area. In the total on group, within the capsulorrhexis margin, significantly lower scores and areas were observed when compared with part-on scores and areas.

CONCLUSION

The increase in PCO up to 3 years was significant. Stabilization in PCO was observed between 3 and 5 years with no difference at 5 years. There was a low incidence of PCO in eyes with total anterior capsule cover over the IOL optic.

Intraindividual comparative analysis of capsule opacification after implantation of 2 single-piece hydrophobic acrylic intraocular lenses models: Three-year follow-up

PURPOSE

To compare the 3-year postoperative anterior (ACO) and posterior (PCO) capsule opacification and the level of anterior capsule retraction after implantation of 2 single-piece hydrophobic acrylic intraocular lens (IOL) models.

SETTING

Hospital of St. John of God, Vienna, Austria.

DESIGN

Comparative randomized controlled double-blind clinical trial.

METHODS

Eyes with bilateral cataract were evaluated. Each patient had an Acrysof SA60AT (interrupted optic edge) IOL implanted in 1 eye (Group A) and a Tecnis ZCB00 (continuous optic edge) IOL implanted in the fellow eye (Group B). One and 3 years postoperatively, PCO was evaluated using Evaluation of Posterior Capsule Opacification software and the ACO level and capsule-retraction level were evaluated and graded subjectively.

RESULTS

The study evaluated 100 eyes of 50 patients ranging from 61 to 80 years. Postoperatively, there were no statistically significant differences in PCO between Group A and Group B at 1 year (0.06 ± 0.12 [SD] and 0.07 ± 0.13, respectively; P = 4.35) or 3 years (0.23 ± 0.36 and 0.22 ± 0.32, respectively; P = .66). In Group A and Group B, ACO was present in 18.0% of eyes and 2.7% of eyes, respectively, at 1 year (P = .03) and in 92.0% and 24.0%, respectively, at 3 years (P < .01). Capsule phimosis (18.0% at 1 year; 30.0% at 3 years) and glistenings (66.0% at 1 year; 86.0% at 3 years) were observed in Group A only.

CONCLUSION

Both IOLs had similarly low PCO rates 3 years postoperatively, although more ACO and capsule retraction were observed in eyes with the interrupted optic edge IOL.

Three-year incidence and factors associated with posterior capsule opacification after cataract surgery: The Australian Prospective Cataract Surgery and Age-related Macular Degeneration Study

PURPOSE

To assess 3-year incidence and associated factors of posterior capsule opacification (PCO) after phacoemulsification surgery.

DESIGN

Cohort study.

METHODS

A total of 1934 consecutive patients aged ≥64 years undergoing phacoemulsification surgery at Westmead Hospital were recruited, of whom 1495 (77.3%) had retroillumination anterior segment images taken of the surgical eyes after 1 month and at a further postoperative visit within 3 years. Severe PCO was defined if the view of the optic disc was obscured, or neodymium-yttrium-aluminum-garnet capsulotomy was performed. Cumulative incidence of PCO was estimated using Kaplan-Meier methods. Associations of PCO with surgeon groups and different types of implanted intraocular lenses (IOLs) were assessed, adjusting for age, sex, diabetes, and ethnicity.

RESULTS

Three-year cumulative incidence of PCO was 38.5% (95% confidence interval [CI] 36.1%-40.9%) among the 1495 patients, including 4.7% (95% CI 3.5%-5.8%) with severe PCO. PCO incidence was higher in: (1) eyes operated on by junior trainees (49%) compared to those by senior ophthalmologist surgeons (36%) (adjusted odds ratio [OR] 1.6, 95% CI 1.2-2.0); and (2) eyes with hydrophobic, 3-piece (either square-edged [51%, OR 2.3, 95% CI 1.4-3.6] or partial-round-edged [39%, OR 1.5, 95% CI 1.1-2.1]), or hydrophilic IOLs (64%, OR 2.9, 95% CI 1.9-4.4) compared to those with single-piece, square-edged, hydrophobic IOLs (34%), after additional adjustment for surgeon group.

CONCLUSIONS

Predominantly mild PCO occurred in one-third of eyes after phacoemulsification surgery. Possible predisposing factors associated with PCO development include surgery performed by ophthalmologic trainees and the use of hydrophilic or other hydrophobic IOLs apart from the single-piece, square-edged one.

Comparison of clinical efficacy: Nd:YAG laser rates after implantation of AcrySof® SN60WF, Akreos® AO-MI60 and Hoya® YA-60BB

PURPOSE

To compare Nd:YAG laser rates following implantation of AcrySof(®) SN60WF (Alcon), Akreos(®) AO-MI60 (Baush & Lomb), and Hoya(®) YA-60BB (Hoya) intraocular lenses.

METHODS

This retrospective study was conducted at three French centers with each implanting at least two of the three implants. Included patients had undergone uncomplicated cataract surgery with at least 3 years of follow-up. Records of patients implanted with one of the three IOL's were drawn randomly from the surgical logs. Postoperative data were obtained from the medical records of either the surgeon or the referring physician. Time elapsing until Nd:YAG laser was analysed using Kaplan-Meier survival curves.

RESULTS

Three hundred eyes were implanted (AcrySof(®) 126, Akreos(®) 89, and Hoya(®) 85). AcrySof(®) recipients were the youngest (AcrySof(®) 72.1, Akreos(®) 76.4, and Hoya(®) 75.2 years of age: P=0.0007). The sex ratio was 4:6 male:female. Follow-up was longest for Hoya eyes (AcrySof(®) 29.4, Akreos(®) 24.6 and Hoya(®) 34.6 months; P=0.0002). Eyes implanted with AcrySof(®) had 1.74 times less chance of Nd:YAG laser treatment than Hoya eyes (P=0.0327) and 3.50 times less than Akreos(®) eyes (P<0.0001). The results remained unchanged when the analysis was restricted to events in the first 24 months (Risk Ratios: Hoya(®)=2.64: P=0.02; and Akreos(®)=4.22: P=0.0001). Adjustment on unbalanced confounding variables did not alter the results.

CONCLUSIONS

Eyes with AcrySof(®) implants required significantly fewer Nd:YAG laser capsulotomies than those with Hoya(®) and Akreos(®) implants and were therefore less subject to Nd:YAG laser treatment complications, thus ensuring better vision at the lowest cost.

Negative dysphotopsia: the enigmatic penumbra

PURPOSE

To determine the cause of negative dysphotopsia and the location, appearance, and relative intensity of such images in pseudophakic eyes.

SETTING

Baylor College of Medicine, Houston, Texas, USA.

DESIGN

Reporting available data addressing a specific clinical question.

METHODS

Negative dysphotopsia was simulated using the Zemax optical design program. The nominal values for the pseudophakic eye model were as follows: IOL power, 20.0 diopters (D); corneal power, 43.5 D; Q value, -0.26; axial IOL depth behind pupil, 0.5 mm; external anterior chamber depth (corneal vertex to iris plane), 4.0 mm; optic diameter, 6.0 mm; pupil diameter, 2.5 mm.

RESULTS

From the first ray-tracing simulation, analysis of the image for the nominal parameters showed 2 annuli (ring-shaped) shadows. The inner annulus shadow was located from a retinal visual field angle of 86.0 to 100.0 degrees (width 14.0 degrees), and the outer annular shadow was located from 105.9 to 123.3 degrees (width 17.4 degrees). Superimposing the inner annulus on the human visual field showed that the shadow would be apparent only temporally, where it is within the limits of the visual field and functional retina. The patient would perceive this as a temporal dark crescent-shaped partial shadow (penumbra).

CONCLUSIONS

Primary optical factors required for negative dysphotopsia are a small pupil, a distance behind the pupil of 0.06 mm or more and 1.23 mm or less for acrylic, a sharp-edged design, and functional nasal retina that extends anterior to the shadow. Secondary factors include a high index of refraction optic material, angle α, and the nasal location of the pupil relative to the eye's optical axis.

FINANCIAL DISCLOSURE

Drs. Zhao and Reisin are employees of and Dr. Holladay is a consultant to Abbott Medical Optics, Inc. No author has a financial or proprietary interest in any material or method mentioned.

Pattern of posterior capsule opacification models 2 years postoperatively with 2 single-piece acrylic intraocular lenses

PURPOSE

To compare posterior capsule opacification (PCO) in eyes with 1 of 2 models of 1-piece acrylic intraocular lenses (IOLs).

SETTING

Ambulatory surgery center.

METHODS

This paired-eye study evaluated patients who had implantation of a Tecnis AAB00 IOL with a continuous optic edge in 1 eye and an AcrySof SA60AT or SN60AT IOL with an interrupted optic edge in the fellow eye. Exclusion criteria were anterior capsule overlap onto the IOL optic of fewer than 360 degrees, neodymium:YAG laser capsulotomy, postoperative time fewer than 24 months or more than 30 months, pseudoexfoliation, glaucoma, history of iritis, and surgical complications that would affect the assessment of PCO. Posterior capsule opacification was assessed using the Evaluation of Posterior Capsular Opacification (EPCO) system on a scale of 0 (none) to 4 (severe opacity with a darkening effect).

RESULTS

In 13 of 14 patients, the eye with the interrupted-edge IOL had a higher EPCO score than the eye with the continuous-edge IOL. The mean EPCO score was 0.39 and 0.08, respectively; the difference was statistically significant (P = .012). The PCO density was greater in eyes with the interrupted-edge IOL, with 35% having an EPCO score of 3 or 4; no eye with a continuous-edge IOL had a score that high.

CONCLUSION

Eyes with an IOL with a continuous 360-degree square edge had significantly less PCO than eyes with an IOL with a square edge that was interrupted at the optic-haptic junction.

Satisfaction and dysphotopsia in the pseudophakic patient

OBJECTIVE

To examine factors that influence satisfaction after uncomplicated cataract surgery.

DESIGN

Retrospective case review and examination of patients.

PARTICIPANTS

Sixty-one consecutive patients, seen at the John A. Moran Eye Center, University of Utah School of Medicine, who had uncomplicated cataract surgery from 1 practice and 40 consecutive control patients who met the inclusion criteria and were willing to participate.

METHODS

Inclusion criteria were best-corrected visual acuity (BCVA) of at least 20/20, without any ocular disease that might affect vision. Patients were given a complete ophthalmic examination, had photos of the intraocular lens (IOL) and capsule taken, and were asked questions about dysphotopsia and satisfaction. A group of patients >65 years old with 20/20 BCVA and without other ophthalmic diagnoses were recruited, asked the same questions, and compared.

RESULTS

The only significant correlation with dissatisfaction was dysphotopsia (r = 0.602, CI 0.42-0.74, p < 0.0001). BCVA, uncorrected visual acuity, posterior capsular opacification, and anterior capsule overlap of the optic were not significantly correlated. The IOL patients were significantly worse for reported glare (p < 0.0001), photophobia (p < 0.0001), and flashes of light (p = 0.0002), but not for halos.

CONCLUSIONS

While satisfaction with cataract removal and IOL placement is high, dysphotopsia is the most important contributor to dissatisfaction and is relatively common. Furthermore, these symptoms are much worse than in age-matched controls. Research seeking to ameliorate dysphotopsia is clinically important.

Incidence of Nd:YAG laser capsulotomies after cataract surgery: comparison of 3 square-edged lenses of different composition

OBJECTIVE

To compare the incidence of Nd:YAG laser treatment following 3 square-edged intraocular lenses (IOLs) of different composition implanted during cataract surgery.

DESIGN

Patient chart analysis.

PARTICIPANTS

Patients aged 50-85 years and given a hydrophobic acrylic IOL (either SA60AT or AR40E) or hydrophilic acrylic IOL (XL-Stabi) were included. Analysis was conducted of 767 eyes treated with SA60AT (n = 250), AR40E (n = 254), or XL-Stabi (n = 263).

METHODS

This retrospective study involved patients who had undergone cataract surgery between 2001 and 2002. Ophthalmology centres were accepted into the study if they used at least 2 of the IOLs being investigated. The medical files of patients fulfilling the inclusion criteria were listed, and eligible cases were selected randomly. Patients' characteristics were obtained from their medical files. Data on postsurgical complications and Nd:YAG laser treatment over 3 years were also extracted. Follow-up data were obtained from the medical files and the patients' ophthalmologists. Time to Nd:YAG laser treatment was analysed using Kaplan-Meier survival curves adjusted with a Cox model.

RESULTS

After 3 years' follow-up the proportions of patients who had not received Nd:YAG laser treatment were 87.0% with SA60AT, 76.6% with AR40E, and 54.6% with XL-Stabi (p < 0.001). Cox's model adjusted for centre effects and the presence of diabetes estimated risk ratios of 2.8 for AR40E (p < 0.0005) and 5.1 for XL-Stabi (p < 0.0001), compared with the reference lens SA60AT.

CONCLUSIONS

Of the 3 square-edged lenses studied, the SA60AT was associated with a lower incidence of Nd:YAG laser treatment than either AR40E or XL-Stabi.

Visual acuity and contrast sensitivity in eyes implanted with aspheric and spherical intraocular lenses

PURPOSE

To compare visual acuity and contrast sensitivity (CS) in eyes implanted with aspheric and spherical intraocular lenses (IOLs) after cataract surgery.

DESIGN

Randomized, prospective study.

PARTICIPANTS

Five hundred twenty-four eyes from 262 cataract surgery patients implanted with 2 IOL models: the AcrySof IQ (262 eyes) and AcrySof SN60AT (262 eyes; Alcon Laboratories, Fort Worth, TX).

METHODS

High-contrast photopic best-corrected distance visual acuity (BCVA) and CS under photopic (85 cd/m(2)) and mesopic (6 cd/m(2)) conditions were measured. Pupil diameter was analyzed for distance vision under both lighting conditions. Follow-up was carried out for 6 months in all patients.

MAIN OUTCOMES MEASURES

Best-corrected distance visual acuity and photopic and mesopic CS after implantation under monocular and binocular conditions.

RESULTS

No statistically significant differences in BCVA were found between either IOL (0.06+/-0.06 and 0.05+/-0.07 logarithm of the minimum angle of resolution units for AcrySof SN60AT and AcrySof IQ groups, respectively; P = 0.091). One hundred percent of patients achieved BCVA of 20/32 or better in both groups. The percentage of patients who achieved BCVA of 20/25 or better was 86.3%. The AcrySof IQ IOL group showed better monocular and binocular CS at 6, 12, and 18 cpd under photopic conditions and at 3, 6, 12, and 18 cpd under mesopic conditions (P<0.001).

CONCLUSIONS

Eyes implanted with the aspheric AcrySof IQ IOL showed better photopic and mesopic CS at medium and high spatial frequencies than eyes implanted with the spherical AcrySof SN60AT IOL. High-contrast photopic BCVA was similar between both IOLs.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Optical coherence tomography evaluation of posterior capsule opacification related to intraocular lens design

PURPOSE

To evaluate posterior capsule opacification (PCO) and the impact of different intraocular lens (IOL) models on PCO characteristics using optical coherence tomography (OCT).

METHODS

Eighty-three eyes with PCO (fibrosis or pearl type) and 32 pseudophakic eyes without PCO were included. Horizontal 3.0 mm long OCT scans of the posterior capsule were obtained. Measurements and means of the peak posterior capsule intensity (PCI) and posterior capsule thickness (PCT) (distance between 2 spikes at posterior capsule) at 3 scan points were recorded. The PCI and PCT were compared with best corrected visual acuity (BCVA) and IOL data.

RESULTS

The PCT was high for IOLs with a rounded edge (P = .001) and with poly(methyl methacrylate) (PMMA) IOLs (P<.001). If the IOL optic was concave-convex, the PCT was higher than if the optic was biconvex (P = .001). The PCT of hydrophilic acrylic IOLs was higher than of hydrophobic acrylic IOLs (P = .04). Multivariate analysis of PCT showed that PMMA was the only factor statistically associated with PCT (P = .02). The worse logMAR BCVA correlated significantly with a higher PCT value (P<.001) but not with PCI (P = .42). An IOL size of 12.5 mm was related to fibrosis-type PCO (odds ratio, 3.14; P = .04).

CONCLUSIONS

The PCT was most affected by IOL characteristics. Poly(methyl methacrylate) IOLs and IOLs with rounded edges were associated with higher PCT. Hydrophilic acrylic IOLs were associated with greater PCT than hydrophobic IOLs. Posterior capsule thickness was a factor in decreased BCVA.

Long-term Effect of 1-Piece and 3-Piece Hydrophobic Acrylic Intraocular Lens on Posterior Capsule Opacification

PURPOSE

To compare the intensity of posterior capsule opacification (PCO) between the 1-piece and 3-piece haptic designs of the foldable hydrophobic acrylic AcrySof intraocular lens (IOL) over a 5-year period.

DESIGN

Randomized, prospective, patient- and examiner-masked clinical trial with intraindividual comparison.

PARTICIPANTS

Fifty-two patients with bilateral age-related cataract (104 eyes).

METHODS

Each study patient had cataract surgery in both eyes and received a 1-piece AcrySof IOL in 1 eye and a 3-piece AcrySof IOL in the other eye. Follow-up examinations were performed at 1 week, 1 month, 6 months, and 1, 2, and 5 years. Digital retroillumination images were obtained of each eye. The amount of posterior capsule opacification (score range, 0-10) was assessed subjectively at the slit lamp and objectively using automated image analysis software 1, 2, and 5 years after surgery.

MAIN OUTCOME MEASURE

Posterior capsule opacification score (scale, 0-10).

RESULTS

There was no significant difference between the 1-piece and 3-piece AcrySof IOL in best-corrected visual acuity, overlap of rhexis and IOL, capsular folds, anterior capsule opacification, and posterior capsule opacification (1-piece AcrySof PCO score, 1.7+/-1.7; 3-piece AcrySof PCO score, 1.3+/-1.4; P = 0.30).

CONCLUSIONS

Modification of the IOL haptic design of the sharp optic edged AcrySof IOL from a 3-piece to a 1-piece haptic design caused no significant change in PCO intensity and neodymium:yttrium-aluminium-garnet laser treatment rate 5 years after surgery.

New intraocular lens for achromatizing the human eye

PURPOSE

To describe the design of a new intraocular lens (IOL) capable of correcting spherical and chromatic aberrations when implanted in the human eye.

SETTING

University of Murcia, Murcia, and University of Valencia, Valencia, Spain.

METHODS

A hybrid singlet achromatic IOL was designed. The IOL has a combination of a refractive and a diffractive surface, with 1 of the surfaces being aspherical. Optical simulations were used to model the polychromatic modulation transfer function (MTF) in pseudophakic eyes to explain the differences in optical quality afforded by the achromatic IOL. Parameters such as focus shift, optical path difference, through-focus, and robustness to tilt and decentering of achromatic IOLs were obtained.

RESULTS

The polychromatic MTF in an eye with a centered, not tilted achromatic IOL was near the diffraction-limited MTF. The focus shift change for the achromatic IOL through the visible spectrum was approximately 0.1 diopter. The polychromatic MTF in an eye with the achromatic IOL would be similar to that in an eye with a spherically centered IOL if the achromatic IOL were decentered 1.0 mm or tilted 4 degrees. The range of centration and tilt error for the achromatic IOL to obtain an optical benefit in the polychromatic MTF was larger than the typical postoperative IOL decentration and tilt errors.

CONCLUSION

The hybrid singlet achromatic IOL design resolved the chromatic aberration problem, improving the overall optical quality in the human eye.

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.

Influence of three-piece and single-piece designs of two sharp-edge optic hydrophobic acrylic intraocular lenses on the prevention of posterior capsule opacification: a prospective, randomised, long-term clinical trial

BACKGROUND

Posterior capsule opacification (PCO) is still a major long-term complication of modern cataract surgery. We evaluated the impact of sharp-edged intraocular lenses (IOLs) with different haptic designs made from the same hydrophobic acrylic material on posterior and anterior lens capsule opacification.

SETTING

Eye clinic of Kaunas University of Medicine, Lithuania. Prospective randomised clinical study.

METHODS

Seventy-four eyes of 74 patients scheduled for cataract surgery were included in a prospective randomised clinical study. Thirty-seven eyes of 37 patients received a three-piece acrylic hydrophobic (AcrySof, MA3OBA, Alcon) IOL; and thirty-seven eyes of 37 patients received a one-piece acrylic hydrophobic (AcrySof, SA3OAL, Alcon) IOL. Visual acuity, anterior capsule opacification (ACO), capsular folds, capsulorrhexis/optic overlapping and posterior capsule opacification (PCO) were evaluated. ACO was assessed subjectively. PCO values in the entire IOL optic area and in the central 3 mm optic zone were assessed using a photographic image-analysis system (EPCO2000). Follow-ups were performed postoperatively at 1 day, 6 months, 1 year and 2 years.

RESULTS

There were no significant differences in best corrected visual acuity, grade of ACO and capsulorrhexis/optic overlapping between IOL types during the follow-up period. Patients in the one-piece acrylic hydrophobic IOL group more frequently presented with capsular folds behind the IOL optic area than those in the three-piece IOL group. In the three-piece acrylic hydrophobic IOL group, PCO values (mean (SD)) of the entire IOL optic area were significantly lower six months postoperative (three-piece: 0.002 (0.009); one-piece: 0.007 (0.017); p=0.04), one year postoperative (three-piece: 0.004 (0.016); one-piece: 0.026 (0.041); p=0.001) as well as one year postoperative in the central 3 mm optic zone (three-piece: 0.000 (0.0002); one-piece: 0.019 (0.049); p=0.001). However, two years postoperative, the PCO values of the groups did not show significant differences (entire IOL optic area: three-piece, 0.136 (0.223); one-piece, 0.154 (0.190); p=0.18; central zone: three-piece, 0.023 (0.065); one-piece: 0.020 (0.039); p=0.44).

CONCLUSION

The 2 year follow-up after cataract surgery showed no significant difference in ACO and PCO development between three-piece and one-piece acrylic hydrophobic intraocular lenses.

Evaluation of lens epithelial cell migration in vivo at the haptic-optic junction of a one-piece hydrophobic acrylic intraocular lens

PURPOSE

To evaluate the pattern of lens epithelial cell (LEC) ingrowth behind the intraocular lens (IOL) optic in patients implanted with the AcrySof SA60AT one-piece IOL.

DESIGN

Retrospective case series.

METHODS

Patients implanted with the AcrySof SA60AT one-piece IOL with complete overlap of the capsulorrhexis and IOL optic and no ocular pathology were selected from the practices of six surgeons. High-resolution digital images of the distribution of LECs were captured. Circumferential location and extent of LEC growth behind the optic were measured.

RESULTS

Mean +/- SD follow-up was 13.2 +/- 1.7 months for 40 patients (mean age 72 years). LEC migration beyond the edge of the IOL optic was displayed by 57.5% (23/40) of patients. LECs migrated into the visual axis in 22.5% (9/40) of patients, leading to a visual acuity of <6/9 (20/30) in 10% (4/40) of patients. Cell migration was located preferentially at the optic-haptic junction. Serial photographs were used to monitor LEC migration over time. In some cases, LECs extended from the opposing optic-haptic junctions to converge in the center of the IOL, creating a path across the optic.

CONCLUSIONS

The optic-haptic junction of the AcrySof one-piece IOL is a point of weakness in the barrier effect of the square-edge IOL design that provides migrating LECs access to the posterior capsule.

Prospective, non-randomised, long term clinical evaluation of a foldable hydrophilic single piece intraocular lens: results of the Centerflex FDA study

BACKGROUND

Owing to the improvement of modern intraocular lenses (IOLs) in terms of design and material, posterior capsule opacification (PCO) usually takes 2-3 years to develop. Thus, long term clinical evaluation of new implants is important.

METHODS

As part of a prospective, non-randomised FDA trial, the Rayner Centerflex, a foldable hydrophilic acrylic, single piece IOL was implanted in one eye of 83 patients (mean age 73.5 (SD 7.0) years). Over 3 years postoperatively, a standardised FDA protocol concerning IOL safety and efficacy was followed including evaluation of spherical equivalent (SE), best corrected distance visual acuity (BCDVA), endothelial cell count (ECC), flare meter values, PCO development, and anterior capsule shrinkage.

RESULTS

Postoperatively, mean SE was stable ranging between -0.3D and 0.17D. After 1-2 months, all patients achieved a BCDVA of 20/40 or better. At 3-6 months postoperatively, mean ECC decreased from 2612 (SD 346) cells/mm2 to 2380 (316) cells/mm2. Mean PCO score for the entire optic increased from 0.20 (0.20) months (3-6 months postoperatively) to 0.87 (0.57) resulting in a Nd:YAG rate of 29.41% after 3 years. No anterior capsule shrinkage was found.

CONCLUSION

The Centerflex showed excellent functional results, low values for endothelial cell loss and inflammatory signs, and no anterior capsule shrinkage. PCO formation was higher compared to other IOLs, which could be explained by the incomplete sharp edge at the optic-haptic junctions representing an "Achilles' heel" for cell ingrowth.

Prospective Intrapatient Comparison of 6.0-Millimeter Optic Single-Piece and 3-Piece Hydrophobic Acrylic Foldable Intraocular Lenses

PURPOSE

To compare postoperative performance and stability of 6.0-mm optic single- and 3-piece acrylic foldable intraocular lenses (IOLs).

DESIGN

Prospective, randomized, self-controlled trial.

PARTICIPANTS

Eighty eyes of 40 patients with bilateral senile cataracts.

INTERVENTION

Phacoemulsification and IOL implantation were performed. One eye of a patient was randomly assigned to the SA60AT single-piece IOL, and the contralateral eye was allocated to the MA60AC 3-piece IOL.

MAIN OUTCOME MEASURES

Best-corrected visual acuity (BCVA), spherical equivalent, aqueous flare intensity, anterior chamber depth, amount of IOL decentration and tilt, area of anterior capsule opening, and degree of posterior capsule opacification (PCO) were measured 2 days, 1 week, and 1, 3, 6, and 12 months after surgery. Specular microscopy was performed at 12 months postoperatively.

RESULTS

In the SA60AT group, the anterior chamber depth did not show significant changes after surgery (P>0.05; paired t test), and the refraction remained highly stable throughout the 1-year study period. The MA60AC group showed significant shallowing of the anterior chamber (P<0.05) and a myopic shift (P<0.05) up to 1 month after surgery. There were no significant differences between the 2 groups (P>0.05) in BCVA, aqueous flare intensity, the amount of IOL decentration, IOL tilt, area of anterior capsule opening, and degree of PCO throughout the 12-month follow-up period.

CONCLUSIONS

Both the SA60AT single-piece and MA60AC 3-piece lenses showed a minimum amount of decentration, tilt, anterior capsule contraction, and PCO. Although the MA60AC showed significant forward shift and myopic refractive changes after surgery, the SA60AT displayed little axial movement associated with highly stable refraction after surgery. This feature of the SA60AT should facilitate earlier spectacle prescription and quicker visual/social rehabilitation of patients after cataract surgery.

Effect of optic material and haptic design on anterior capsule opacification and capsulorrhexis contraction

PURPOSE

To examine the influence of optic material (silicone and hydrophobic acrylic) and haptic design (one-piece and three-piece open loop) of sharp optic edge intraocular lenses (IOL) on anterior capsule opacification (ACO) and capsulorrhexis contraction.

DESIGN

Randomized, controlled, double-blind clinical trial with intraindividual comparison.

METHODS

This study was performed at the Department of Ophthalmology, Medical University of Vienna, Austria, and comprised 210 eyes of 105 patients with bilateral age-related cataract. In group 1 (n = 53 patients), a three-piece acrylic IOL was compared with a three-piece silicone IOL. In group 2 (n = 52 patients), the three-piece acrylic IOL was compared with the one-piece acrylic IOL. One year after the operation, standardized digital slit-lamp images of ACO were taken; 1 week and 1 year after the operation, digital retroillumination images were taken to assess capsulorrhexis size. The intensity of ACO was graded objectively (score, 0% to 100%), and the capsulorrhexis area (square millimeters) was determined objectively.

RESULTS

One year after surgery, the mean ACO score was 21% for the acrylic and 20% for the silicone IOL (P = .4) in group 1 and 18% for both the three-piece and one-piece acrylic IOLs (P = .87) in group 2. Concerning the amount of capsulorrhexis contraction, there was no significant difference between the IOL types that were evaluated in this study (after Bonferroni-Holm correction, P > .05).

CONCLUSION

In the hydrophobic sharp optic edge IOLs that were examined, neither the optic material nor the haptic design had an influence on the amount of ACO or capsulorrhexis contraction.

Evaluation of posterior capsule opacification using a new posterior view method in rabbits

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.

Nd:YAG capsulotomy rates after use of the AcrySof acrylic three piece and one piece intraocular lenses

BACKGROUND/AIM

Acrylic lens size and shape may influence the rate of posterior capsule opacification (PCO) and need for Nd:YAG capsulotomy. The aim of this study is to compare the Nd:YAG capsulotomy rate of the three piece acrylic/PMMA AcrySof MA series lens with the one piece acrylic AcrySof SA series lens.

METHODS

434 eyes of 329 patients who had cataract extraction and implantation of one of four types of intraocular lenses (IOLs) were evaluated for rate of Nd:YAG capsulotomy. 176 eyes received the acrylic AcrySof MA30AC IOL, 71 eyes the acrylic AcrySof MA60AC IOL, 45 eyes the acrylic AcrySof SA30AL IOL, and 142 eyes the acrylic AcrySof SA60AT IOL.

RESULTS

The rates of Nd:YAG capsulotomy with the three piece IOL (MA30AC/MA60AC) and the one piece IOL (SA30AL/SA60AT) were 1.2% and 2.1% at 6 months, 2.8% and 5.9% at 12 months, and 3.6% and 7.5% at 24 months, respectively. The incidence of Nd:YAG capsulotomy was higher in patients who received the one piece IOL (p=0.01, log rank test). There was no difference in Nd:YAG capsulotomy rates when comparing lens optic size, age, sex, history of pars plana vitrectomy, and diabetes mellitus.

CONCLUSIONS

This study shows a greater incidence of Nd:YAG capsulotomy in patients who receive one piece acrylic AcrySof lenses when compared to those who receive three piece acrylic AcrySof lenses.

Changing indications for and improving outcomes of intraocular lens exchange

PURPOSE

To evaluate the indications for and outcomes of intraocular lens (IOL) exchange at the same clinical setting over the past decade, as well as compare the efficacy and safety of anterior chamber lens (AC-IOL) and posterior chamber lens (PC-IOL) implantation for IOL exchange.

DESIGN

Retrospective, nonrandomized case series.

METHODS

The charts of all patients who had an IOL exchange at the Eye Institute of Utah between January 1998 and December 2004 were reviewed. The rate, indications, and outcomes are compared with the data of our previous study conducted between 1986 and 1990.

RESULTS

This study comprised 51 eyes of 51 consecutive patients. The rate of IOL exchange was 0.77% of all cataract surgeries during the time considered. Incorrect IOL power (41.2%), decentration/dislocation (37.3%), and glare (7.8%) were the most common indications for IOL exchange. An AC-IOL was used in 14 eyes (27.5%) and a PC-IOL in 37 eyes (72.5%) for IOL exchange. None of the PC-IOLs was sutured to the sclera or iris. Overall, 90.2% of patients obtained a best-spectacle corrected visual acuity (BSCVA) of 20/40 or better. All eyes in AC-IOL group and 94.6% of eyes in PC-IOL group maintained within 1 line or improved 2 to 5 lines of the pre-exchange vision.

CONCLUSIONS

The improvements in IOL design and materials as well as surgical techniques have greatly minimized the incidence, changed the indications for, and improved the visual outcomes of IOL exchange over the past decade. Our study suggests that the open loop, flexible AC-IOL poses no greater risk than PC-IOL with respect to visual outcome and safety for IOL exchange. An AC-IOL may be preferable to a PC-IOL suture fixation for IOL exchange in the absence of posterior capsular support.

[Influence of intraocular lens material and design on the development of posterior capsule opacification]

Based on the literature of 1999-2005, we attempted to clarify the influence of material and design of an intraocular lens (IOL) on the development of posterior capsule opacification (PCO) and identify the future problems to be solved. The sharp edge design of an IOL has significantly reduced PCO in recent years. Histopathological studies showed that a sharp capsular bend was formed at the sharp posterior optic edge, and the migration of lens epithelial cells was obviously inhibited at the site. Experimental and clinical studies suggest that the sharper the edge is, the sharper the capsular bend, and the greater the preventive effect, regardless of IOL material. The sharp capsule bend appears to represent a physical hindrance, which may induce contact inhibition of cell movement. How material participates in the preventive effect should be clarified in a future study. Thus, at the moment, the formation of capsular bend at the posterior optic edge appears to be the decisive criterion to evaluate the influence of IOL material and design on the development of PCO. Optimization of design and material of an IOL, which facilitates capsular bend formation as sharply and quickly as possible, may reduce PCO to a clinically negligible level.

Choice of intraocular lens may not affect refractive stability following cataract surgery

PURPOSE

To assess whether the choice of an intraocular lens (IOL) with rigid haptics (Sensar) or an IOL with pliable haptics (Acrysof) has an effect on refractive stability following cataract surgery.

METHODS

Seventy-three patients were recruited consecutively as they returned for their 6-month visit following cataract surgery. There were 37 patients who had received an Acrysof IOL and 36 who had received a Sensar IOL. Each patient had their refractive error measured at the 1-month postoperative visit. At the 6-month follow-up visit, refraction was repeated. The change in refractive error was then compared between IOL groups and other factors that may affect postoperative refractive stability including preoperative refraction, axial length, keratometry, wound type and wound meridian.

RESULTS

An Acrysof IOL showed minimal myopic movement, whereas a Sensar IOL was more likely to move hypermetropically. However, this difference was not statistically significant (t=1.92; P=0.06). The magnitude of the shift in spherical equivalent in either direction for the Acrysof group was 0.37 +/- 0.35 D and for the Sensar group was 0.28 +/- 0.31 D. Again, this difference was not statistically significant (t=1.17; P=0.25). However, preoperative anterior chamber depth was associated with postoperative refractive shift (t=2.66; P=0.009). Furthermore, patients with a scleral wound showed a small against-the-rule shift in cylindrical refractive error. No other factors were associated with postoperative refractive shift amongst the sample.

CONCLUSIONS

There were no clinically significant differences in postoperative refractive stability between the Acrysof and Sensar groups. However, preoperative anterior chamber depth was associated with the magnitude of shift in spherical equivalent.