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

How do intraocular lens materials influence the outcome of cataract surgery?

PURPOSE OF REVIEW

This review summarizes the evidence on the effect of intraocular lens (IOL) material on the outcomes of cataract surgery, as well as on the surgical procedure itself.

RECENT FINDINGS

Differences in capsular biocompatibility between IOL materials lead to variations in capsular stability and posterior capsule opacification (PCO), while differences in uveal biocompatibility affect postoperative inflammatory response.

SUMMARY

Refractive outcomes are affected by both incision size and the rotational stability of toric IOLs. Small incision sizes favour hydrophilic IOLs. Rotational stability of hydrophobic and hydrophilic IOLs were comparable in recent studies. Visual outcomes are affected by chromatic aberrations, dysphotopsia, lens opacifications and PCO. Hydrophilic IOLs are associated with reduced chromatic dispersion. Hydrophobic IOL opacifications are caused by sub-surface glistenings, while hydrophilic IOL opacifications are due to surface calcifications. Some surgeries, including pars plana vitrectomy and lamellar corneal transplants, were shown to increase the risk of IOL calcifications, although the mechanism is still unknown. Hydrophilic IOLs have greater ease of manipulation, greater resistance to IOL damage, and higher uveal biocompatibility. Hydrophobic IOLs show better PCO prevention than hydrophilic IOLs, and should be preferred in highly myopic eyes where Nd:YAG capsulotomy might increase the risk of retinal detachment.

Incorrectly Focused Neodymium:Yttrium-Aluminum-Garnet (Nd:YAG) Laser Beam Leads to Massive Destructive Effects in Small-Aperture (Pinhole) Intraocular Lenses

INTRODUCTION

Pinhole intraocular lenses (IOLs) were developed to improve reading by compensating for loss of accommodative function. The IC-8® Apthera™ is a small-aperture presbyopia-correcting IOL that combines the proven principle of small-aperture optics with an aspheric monofocal lens to deliver a continuous range of vision for patients with cataracts from distance to near vision. Posterior capsule opacification is the most common sequela after cataract surgery. It is effectively treated by laser capsulotomy. However, if the laser beam is incorrectly focused, the IOL can be permanently damaged (pits/shots).

METHODS

In this experimental study, yttrium-aluminum-garnet (YAG) pits were purposefully created. Defects were analyzed and compared between the periphery of the ring in the clear area of the hydrophobic acrylic lens and at the carbon black (CB)-polyvinylidene fluoride (PVDF) filtering component (FilterRing™) of the pinhole lens. All defects were made using identical settings/energy levels (2.6 mJ). The damage induced to the IC-8® Apthera™ IOL was examined by low-magnification images, light microscopy, scanning electron microscopy, and micro-computed tomography (micro-CT).

RESULTS

YAG defects in the carbon black filter ring were much more severe than those in the clear zone due to the high absorption of the carbon black. Massive defects and destruction of the lens with tearing out of fragments and particles were observed. The missing volume calculated from the micro-CT reconstruction was 0.266 mm3, which is 1.6% of the entire IOL volume, or more than 1000 times the volume damaged in the largest shot in the periphery.

CONCLUSION

Based on the results, we highly recommend using the lowest possible energy levels, posterior offset setting, and circular pattern for maximum safety when performing laser capsulotomy with pinhole implants. Care should be taken to avoid creating irreversible iatrogenic defects that may affect overall quality. The safest area for performing capsulotomy seems to be the periphery of the ring segment. Video available for this article.

Evaluation of a Novel Zonular Tension Restoring Accommodating Silicone IOL Design: Pilocarpine and Cyclopentolate-Induced Effect 20 Months after Implantation

Purpose

To investigate a novel zonular-stress restoring accommodating 1-piece silicone IOL. Setting. Angeles City, Philippines.

Design

Prospective randomized bilateral study.

Methods

Each patient received a study IOL (ActaLens™, Emmetrope, La Canada, CA) in one eye and a control IOL (CrystaLens® AO, B&L, USA, or an AcrySof IQ®, Alcon, USA) in the contralateral eye to allow for intraindividual comparison. At the 20-month follow-up, two measurement days were set to measure all eyes before and after instilling 2% pilocarpine on the first day and 1% cyclopentolate on the second measurement day using an optical biometry device (Lenstar, Haag-Streit AG, Switzerland), respectively. PCO was graded by two examiners independently at the slit lamp.

Results

In total, 16 eyes of 8 patients were included. In the study group and the control group, the pilocarpine-induced ACD shift was 0.32 mm (SD: 0.12) (p=0.014) and 0.04 mm (SD: 0.16) (p=0.854), respectively. In the study group and the control group, the mean cyclopentolate-induced ACD shift was 0.14 (SD: 0.06) (p=0.014) and 0.03 mm (SD: 0.03) (p=0.181), respectively. PCO and Nd : YAG rates were higher in the study group, but differences were not found to be significant (AcrySof vs. ActaLens p=0.100 and CrystaLens vs. ActaLens p=0.174).

Conclusion

The investigated IOL is a novel concept for an accommodating IOL, and results showed a moderate pilocarpine-induced forward shift of the IOL 20 months following implantation. For all patients, the investigated IOL seems to have a higher PCO rate compared to standard monofocal IOLs.

Long-Term Clinically Significant Posterior Capsular Opacification Development Pattern in Eyes Implanted with an Aspheric Monofocal Intraocular Lens with a Square Optic Edge

Purpose

To analyse the posterior capsular opacification (PCO) development pattern in the long term in eyes implanted with a monofocal intraocular lens (IOL) with a square edge all around the optic.

Methods

Longitudinal retrospective study is data analyzed from a total of 7059 eyes from 4764 patients (mean age: 75.8 years) undergoing cataract surgery with implantation of an aspheric monofocal IOL (Bi-Flex HL 677AB/677P, Medicontur, Budapest, Hungary). These data were retrospectively collected using the electronic medical record of the hospitals involved. Nd : YAG capsulotomy rates were calculated per year during a follow-up of more than 10 years. The Kaplan–Meier analysis was used to establish the transparent capsule survival rate.

Results

The Nd : YAG capsulotomy rate increased from 1.1% at 1 year postoperatively to 17.2% at 5 years after surgery. No significant differences were found between eyes with and without capsulotomy in terms of age (p = 0.202), gender (p = 0.061), type of anaesthesia used (p = 0.128), and presence of conditions such as hard cataract (p = 0.111) or pseudoexfoliation (p = 0.137). IOL power was significantly lower in those eyes of patients requiring Nd : YAG capsulotomy during the follow-up (p < 0.001). Significantly more eyes implanted with the preloaded model of the IOL required capsulotomy (p < 0.001). Mean survival time and rate were 9.38 years and 85.9%, respectively.

Conclusions

Most eyes undergoing cataract with implantation of the Bi-Flex IOL do not develop a clinically significant PCO requiring Nd : YAG capsulotomy in the long term. IOL material and design may be the main factors accounting for this finding.

Intraocular lens optic edge design for the prevention of posterior capsule opacification after cataract surgery

BACKGROUND

Posterior capsule opacification (PCO) is a clouding of the posterior part of the lens capsule, a skin-like transparent structure, which surrounds the crystalline lens in the human eye. PCO is the most common postoperative complication following modern cataract surgery with implantation of a posterior chamber intraocular lens (IOL). The main symptoms of PCO are a decrease in visual acuity, 'cloudy', blurred vision and reduced contrast sensitivity. PCO is treated with a neodymium:YAG (Nd:YAG) laser to create a small opening in the opaque capsule and regain a clear central visual axis. This capsulotomy might cause further ocular complications, such as raised intraocular pressure or swelling of the central retina (macular oedema). This procedure is also a significant financial burden for health care systems worldwide. In recent decades, there have been advances in the selection of IOL materials and optimisation of IOL designs to help prevent PCO formation after cataract surgery. These include changes to the side structures holding the lens in the centre of the lens capsule bag, called IOL haptics, and IOL optic edge designs.

OBJECTIVES

To compare the effects of different IOL optic edge designs on PCO after cataract surgery.

SEARCH METHODS

We searched CENTRAL, Ovid MEDLINE, Ovid Embase, Latin American and Caribbean Health Sciences Literature Database (LILACS), the ISRCTN registry, ClinicalTrials.gov and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) up to 17 November 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared different types of IOL optic edge design. Our prespecified primary outcome was the proportion of eyes with Nd:YAG capsulotomy one year after surgery. Secondary outcomes included PCO score, best-corrected distance visual acuity (BCDVA) and quality of life score at one year. Due to availability of important long-term data, we also presented data at longer-term follow-up which is a post hoc change to our protocol.

DATA COLLECTION AND ANALYSIS

We used standard methods expected by Cochrane and the GRADE approach to assess the certainty of the evidence.

MAIN RESULTS

We included 10 studies (1065 people, 1834 eyes) that compared sharp- and round-edged IOLs. Eight of these studies were within-person studies whereby one eye received a sharp-edged IOL and the fellow eye a round-edged IOL. The IOL materials were acrylic (2 studies), silicone (4 studies), polymethyl methacrylate (PMMA, 3 studies) and different materials (1 study). The studies were conducted in Austria, Germany, India, Japan, Sweden and the UK. Five studies were at high risk of bias in at least one domain. We judged two studies to be at low risk of bias in all domains. There were few cases of Nd:YAG capsulotomy at one year (primary outcome): 1/371 in sharp-edged and 4/371 in round-edged groups. The effect estimate was in favour of sharp-edged IOLs but the confidence intervals were very wide and compatible with higher or lower chance of Nd:YAG capsulotomy in sharp-edged compared with round-edged lenses (Peto odds ratio (OR) 0.30, 95% CI 0.05 to 1.74; I² = 0%; 6 studies, 742 eyes). This corresponds to seven fewer cases of Nd:YAG capsulotomy per 1000 sharp-edged IOLs inserted compared with round-edged IOLs (95% CI 9 fewer to 7 more). We judged this as low-certainty evidence, downgrading for imprecision and risk of bias. A similar reduced risk of Nd:YAG capsulotomy in sharp-edge compared with round-edge IOLs was seen at two, three and five years but as the number of Nd:YAG capsulotomy events increased with longer follow-up this effect was more precisely measured at longer follow-up: two years, risk ratio (RR) 0.35 (0.16 to 0.80); 703 eyes (6 studies); 89 fewer cases per 1000; three years, RR 0.21 (0.11 to 0.41); 538 eyes (6 studies); 170 fewer cases per 1000; five years, RR 0.21 (0.10 to 0.45); 306 eyes (4 studies); 331 fewer cases per 1000. Data at 9 years and 12 years were only available from one study. All studies reported a PCO score. Four studies reported the AQUA (Automated Quantification of After-Cataract) score, four studies reported the EPCO (Evaluation of PCO) score and two studies reported another method of quantifying PCO. It was not possible to pool these data due to the way they were reported, but all studies consistently reported a statistically significant lower average PCO score (of the order of 0.5 to 3 units) with sharp-edged IOLs compared with round-edged IOLs. We judged this to be moderate-certainty evidence downgrading for risk of bias. The logMAR visual acuity score was lower (better) in eyes that received a sharp-edged IOL but the difference was small and likely to be clinically unimportant at one year (mean difference (MD) -0.06 logMAR, 95% CI -0.12 to 0; 2 studies, 153 eyes; low-certainty evidence). Similar effects were seen at longer follow-up periods but non-statistically significant data were less fully reported: two years MD -0.01 logMAR (-0.05 to 0.02); 2 studies, 311 eyes; three years MD -0.09 logMAR (-0.22 to 0.03); 2 studies, 117 eyes; data at five years only available from one study. None of the studies reported quality of life. Very low-certainty evidence on adverse events did not suggest any important differences between the groups.

AUTHORS' CONCLUSIONS

This review provides evidence that sharp-edged IOLs are likely to be associated with less PCO formation than round-edged IOLs, with less Nd:YAG capsulotomy. The effects on visual acuity were less certain. The impact of these lenses on quality of life has not been assessed and there are only very low-certainty comparative data on adverse events.

Evaluation of Nd:YAG Laser Capsulotomy Rates in a Real-Life Population

Objective

The objective of this study was to assess the rate of posterior capsule opacification (PCO), under “real-life” conditions, as measured by rates of Nd:YAG laser intervention, rather than from a controlled study from which patients with conditions predisposing to PCO have been excluded.

Methods and Analysis

This was a retrospective, multicenter study in an unselected consecutive cohort of patients undergoing surgery for senile cataract. Patients aged 18 years and older, previously implanted with the CT LUCIA 611P IOL, were contacted at 12, 18 and 24 months to ascertain if they had received Nd:YAG laser treatment. There was an additional assessment at 36 months at the Austrian centre.

Results

A total of 200 patients were recruited at two centers. Laser capsulotomy rates were 4.5% at 1 year and 10% by year 2 and 12% by year 3. Three Nd:YAG capsulotomies, carried out at other external centers, were performed for reasons other than PCO, including astigmatism, epiretinal membrane and ARMD. If these patients are excluded, the true rate of Nd:YAG carried out for PCO at 1 year was 3.5% and at 2 years was 8.5%.

Conclusion

It is critical to ensure that Nd:YAG capsulotomies are being performed only for the correct clinical reason. Carrying out unnecessary procedures places the patient at risk of adverse events, is a cost to the healthcare system, and is likely to have no direct visual benefit for the patient. In PCO studies, it should be a requirement to document the fibrosis grade to confirm that Nd:YAG capsulotomy was correctly indicated.

Posterior Capsule Opacification after Cataract Surgery in Children Over Five Years of Age with Square-edge Hydrophobic versus Hydrophilic Acrylic Intraocular Lenses: A Prospective Randomized Study

OBJECTIVE

To compare the effects of hydrophobic and hydrophilic materials in square-edged acrylic intraocular lenses (IOLs) on the development of posterior capsule opacification (PCO) after pediatric cataract surgery.

METHODS

Patients were randomly assigned to group 1 (hydrophobic acrylic square-edged IOLs; 13 eyes) or group 2 (hydrophilic acrylic square-edged IOLs; 13 eyes). The study evaluated PCO rates using Evaluation of Posterior Capsule Opacification (EPCO) 2000 software at one, three, six and 12 months postoperatively. Postoperative measurements also included corrected distance visual acuity (CDVA), neodymium:yttrium-aluminum-garnet (Nd:YAG) capsulotomy and postoperative complications other than PCO.

RESULTS

Both groups had significant increases in PCO rates after one year. Comparison of the groups showed no significant differences in the EPCO scores at three (group 1, 0.007±0.016 vs group 2, 0.008±0.014; p=0.830), six (group 1, 0.062±0.103 vs group 2, 0.021±0.023; p=0.184), or twelve months postoperatively (group 1, 0.200±0.193 vs group 2, 0.192±0.138; p=0.902). We also found no significant group differences regarding the change (delta, Δ) in EPCO scores between three and six months (group 1, 0.055±0.09 vs group 2, 0.013±0.02; p=0.113) or between six and twelve months postoperatively (group 1, 0.139±0.14 vs group 2, 0.171±0.14; p=0.567). Twenty-three percent of patients required Nd:YAG capsulotomy at the twelve-month visit.

CONCLUSIONS

No differences in PCO rates were found between hydrophobic and hydrophilic acrylic square-edged IOLs in children between five and twelve years of age at one year of follow-up.

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.

Open-capsule intraocular lens to prevent posterior capsule opacification

PURPOSE

To develop a single-piece open-capsule intraocular lens (IOL) that can be inserted through a small incision and that prevents posterior capsule opacification (PCO) by expanding the capsule and circulating aqueous humor into the capsular bag.

SETTING

Department of Ophthalmology, Dokkyo Medical University, Tochigi, Japan.

DESIGN

Experimental study.

METHOD

Using the same hydrophobic acrylic material as the NY-60 IOL, a prototype open-capsule IOL was constructed. The IOL has a single optic and 2 haptics, with a 2.8 mm high spacer and holes through which aqueous humor circulates into the capsular bag by separating the anterior capsule from the posterior capsule and expanding the capsule. The open-capsule IOL or NY-60 (as a control group) was inserted in rabbit eyes. Posterior capsule opacification development was evaluated by measuring the thickness of the cell layer at the center of the posterior capsule on histopathologic specimens and statistically comparing the thickness between the open-capsule IOL group and control group.

RESULTS

The open-capsule IOL could be inserted through a 3.2 mm corneal incision using a D cartridge. The mean thickness of the cell layer at the center of the posterior capsule was 4.78 μm ± 2.61 (SD) in the open-capsule IOL group and 101.14 ± 25.19 μm in the control group and was significantly smaller in the open-capsule IOL group.

CONCLUSION

The prototype single-piece IOL could be implanted through a small incision and prevented PCO by expanding the lens capsule and circulating aqueous humor into the capsular bag.

Incidence of posterior capsular opacification requiring Nd:YAG capsulotomy after cataract surgery and implantation of enVista® MX60 IOL

PURPOSE

To evaluate incidence of posterior capsule opacification requiring Nd:YAG capsulotomy over 3 years in a large series of eyes implanted with the enVista^® MX60 Intraocular Lens (IOL).

METHODS

A university-based, single-center, observational study of patients' medical records was conducted. Uneventful cataract surgery patients with in-the-bag implantations of the enVista^® MX60 IOL with a minimum of 24 months follow-up were included in the study. Exclusion criteria were insufficient follow-up (<24 months), intraoperative complications and combined surgery. The primary outcome measure was rate of YAG laser capsulotomy, while secondary outcome measures were time to YAG laser capsulotomy and rate of glistenings.

RESULTS

A total of 245 eyes of 143 patients received the MX60 IOL and were followed in the same center. Of these, 226 eyes were included in the study. Mean age was 80.7±8.3 years and M/F ratio was 42/101 (29.4/70.6%). The mean preoperative distance (logMAR) visual acuity was 0.67±0.5, while postoperatively it was 0.31±0.5 and 0.32±0.5 at the last visit. The Mean±SD follow-up time (min-max) was 35.2±7.2, (24-48.4) months. The incidence of Nd:YAG capsulotomy over 3 years was 5/226 (2.2%). Average time between surgery and Nd:YAG capsulotomy was 32.17 months. Univariate analysis of age, gender, presence of comorbidity and baseline visual acuity found no predictive factors for capsulotomy. No glistenings were reported at any postoperative visit.

CONCLUSION

The three-year cumulative incidence of PCO requiring Nd:YAG laser capsulotomy was 2.2% for the enVista^® MX-60 IOL, with no glistenings observed during follow-up. This low rate confirms the excellent safety profile of this IOL.

[Posterior capsule opacification, glistenings and visual outcomes: 3 years after implantation of a new hydrophobic IOL]

PURPOSE

To evaluate the visual outcomes, the incidence of glistenings and posterior capsule opacification in a series of consecutive eyes with a new blue light-filtering hydrophobic acrylic intraocular lens (IOL) SETTING: Service d'ophtalmologie, clinique Beausoleil, avenue de Lodève, Montpellier.

DESIGN

Retrospective, cross-sectional study.

METHODS

This study included a series of 66 eyes that underwent routine cataract surgery with PODEye (PhysIOL SA, Liège, Belgium) monofocal IOL implantation between May 2011 and November 2011. These eyes were compared for glistenings with patients implanted with Acrysof material IOL (Alcon, Fort Worth, USA) who had a routine postoperative examination between January 2015 and August 2015. The safety of the IOL was assessed by visual acuity outcomes, as well as rotational stability, centration and postoperative medication. The incidence and severity of glistenings were evaluated with the slit lamp. Glistenings and PCO were graded subjectively (0=absent; 1=moderate; 2=dense). Follow-up was 3 years.

RESULTS

The mean visual acuity after PODEye implantation was 0.98±0.05 (n=50) in decimal notation at 1 year, 0.98±0.06 at 1 week, (n=66), 1.00±0.01 at 3 weeks (n=64) and 0.99±0.02 at 3 months (n=59). The IOL displayed stable positioning in all axes. Glistenings of grade 2 were absent in the G-Free/PODEye group, whereas they were significantly present in the Acrysof group. One out of 43 eyes at 3-year follow-up underwent YAG capulotomy at 37 months. Sixty-six percent of eyes had no PCO (grade 0) at 3 years.

CONCLUSIONS

The PODEye IOL was safe and stable. Glistenings grade 2 or more were not found with this blue light-filtering hydrophobic acrylic IOL. PCO occurrence was low at three years.

Comparing capsular bag performance of a hydrophilic and a hydrophobic intraocular lens: A randomised two-centre study

Purpose:

To evaluate the capsular bag performance and posterior capsule opacification development of two intraocular lenses differing in material and design.

Methods:

This study included patients who were scheduled for cataract surgery and compared a hydrophilic intraocular lens (Super flex® intraocular lens; Rayner Surgical, Worthing, UK) with a hydrophobic intraocular lens (AcrySof® SA60AT; Alcon, Fort Worth, TX, USA). Follow-ups were performed 1 month and 2 years after cataract surgery, including a slit lamp examination and retroillumination images.

Results:

In total, 80 eyes of 80 patients were recruited. At the 1-month follow-up, 6 of 39 cases had a gap between the posterior lens capsule and intraocular lens (1 case in the hydrophilic intraocular lens group and 5 cases in the hydrophobic intraocular lens group; p = 0.348). Objective and subjective posterior capsule opacification scoring showed no statistically significant difference between both groups (p = 0.123).

Conclusion:

Both intraocular lens showed a good capsular bag performance and a relatively low posterior capsule opacification development within the first 2 years after surgery.

Long-Term Observation of Triplex Surgery for Cataract after Phakic 6H Implantation for Super High Myopia

Purpose. To analyze the safety, effectiveness, and stability of triplex surgery for phakic 6H anterior chamber phakic intraocular lens explantation and phacoemulsification with in-the-bag IOL implantation for super high myopia in long-term observations. Methods. This retrospective case series evaluated 16 eyes of 10 patients who underwent triplex surgery. Best corrected visual acuity (BCVA), endothelial cell density (ECD), and associated adverse events were evaluated. Results. The mean follow-up time after the triplex surgery was 46 ± 14 months. The mean logMAR BCVA was significantly improved after triplex surgery (P = 0.047). One eye developed endophthalmitis five days postoperatively and underwent pars plana vitrectomy (PPV). Five eyes with preoperative severe endothelial cell loss developed corneal decompensation and underwent keratoplasty at a mean time of 9.4 ± 2.6 months after the triplex surgery. One eye had graft failure and underwent a second keratoplasty. The eye developed rhegmatogenous retinal detachment and underwent PPV with silicone oil 18 months later. ECD before the triplex surgery was not significantly different compared with that at last follow-up (P = 0.495) apart from these five eyes. Three eyes (18.8%) developed posterior capsule opacification. Conclusions. Triplex surgery was safe and effective for phakic 6H related complicated cataracts. Early extraction before severe ECD loss is recommended.

Adhesion of the posterior capsule to different intraocular lenses following cataract surgery

PURPOSE

To investigate the prevalence and morphologic and clinical features of posterior capsule-optic inadhesion following cataract surgery.

METHODS

In this prospective cohort study, we examined 518 consecutive patients who had undergone uneventful phacoemulsification and posterior chamber intraocular lens (IOL) implantation. They were assigned into five groups based on the type of IOL used: MC X11 ASP, Rayner 920H A, ZCB00, SN60WF and KS-3Ai. Routine ophthalmic examinations were performed. Patients were followed up at 1 day, 1 week, and 1 and 2 months postsurgery. Anterior segment photography, Scheimpflug imaging and KR-1W aberrometry were conducted after the patients' pupils were dilated.

RESULTS

The overall rate of posterior capsule-optic inadhesion on the first day after surgery was 215/518 (41.5%), and it decreased to 37/518 (7.1%) at 2 months postsurgery. Posterior capsule-optic inadhesion can be morphologically classified into five types with three outcomes, of which gradual absorption of the accumulated fluid predominated for all IOLs. The clinical characteristics of patients with inadhesion varied with IOL type. Notably, visual quality data (Strehl ratios and modulation transfer function) were poorer in patients with posterior capsule-optic inadhesion, especially in those with irregular forms of suspension. Four cases of capsular contraction syndrome were identified among the patients with inadhesion.

CONCLUSIONS

Posterior capsule-optic inadhesion is a prevalent capsule-IOL interaction following cataract surgery. Although the accumulated fluid is absorbed in the majority of patients, its adverse effects on visual outcomes, especially visual quality in the operated eye(s), must not be underestimated in patients with persistent inadhesion.

Epidemiological evaluation of YAG capsulotomy incidence for posterior capsule opacification in various intraocular lenses in Japanese eyes

Background and objective

We investigated the yttrium aluminum garnet (YAG) capsulotomy rates in various intraocular lenses (IOLs).

Study design/patients and methods

We retrospectively analyzed 23,440 eyes implanted with either MA60BM, MA60AC, VA-60BB, CeeOnEdge, Clariflex, Technis Z9002, SI-40NB, or UV26T IOLs. We calculated the YAG capsulotomy rates at 1, 3, 5, and 10 years post lens implantation.

Results

YAG capsulotomy rates at 3 years postimplantation for the eight groups of IOLs were, respectively, 3.7%, 3.9%, 23.7%, 3.4%, 4.5%, 4.7%, 10.4%, and 21.0%. YAG capsulotomy rates at 10 years postimplantation for the MA60BM and SI-40NB IOLs were, respectively, 9.1% and 15% (P<0.05). The average YAG rates for all sharp-edged and round-edged IOLs at 5 years postimplantation were, respectively, 5.2%±0.7% and 25.6%±9.0% (P<0.05).

Conclusion

In all studied IOLs, posterior capsule opacification prevention seemed to be associated with the posterior optic sharp-edge design. Round-edged silicone IOLs may also retard posterior capsule opacification formation, though not as much as sharp-edged IOLs. As the follow-up period progressed, round-edged silicone IOLs showed significantly higher YAG rates than sharp-edged IOLs.

Comparison of posterior capsule opacification at 360-degree square edge hydrophilic and sharp edge hydrophobic acrylic intraocular lens in diabetic patients

AIM

To compare posterior capsule opacification (PCO) degree and visual functions after phacoemulsification in eyes implanted with 360-degree square edge hydrophilic acrylic intraocular lens (IOL) (570C C-flex, Rayner) and sharp edge hydrophobic acrylic IOL (Sensar AR40e, AMO) in diabetic patients.

METHODS

Sixty diabetic patients underwent uneventful phacoemulsification and randomly implanted one of the two IOLs. The PCO value was measured by retroillumination photographs and Evaluation of Posterior Capsule Opacification (EPCO) 2000 image-analysis software at 1, 6, 12, and 24mo after surgery. Visual acuity, and contrast sensitivity in photopic and mesopic conditions were also examined at each follow up time point. The incidence of eye that required Nd:YAG laser posterior capsulotomy were also compared.

RESULTS

There was not any statistically significant difference in PCO scores between Rayner C-flex 570C group and Sensar AR40e group at each follow up time point. Visual acuity, Nd:YAG capsulotomy incidence and contrast sensitivity also had no significant difference during the 24mo follow-up.

CONCLUSION

For diabetic patients, Rayner 570C C-flex and Sensar AR40e IOLs are same effective for prevent PCO. The 360-degree square edge design maybe is a good alternative technique to improve PCO prevention.

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.

Five-year incidence of Nd:YAG laser capsulotomy and association with in vitro proliferation of lens epithelial cells from individual specimens: a case control study

Background

The aims of this study were to determine the 5-year incidence of posterior capsule opacification (PCO) requiring Nd:YAG laser capsulotomy in a representative mixed cohort of cataract patients, to determine risk factors for PCO and to investigate possible association with growth of human lens epithelial cells (HLEC) in vitro.

Methods

Pieces of the anterior lens capsule and adhering HLEC were obtained at cataract surgery and cultured individually. After one and two weeks respectively, cultured cells were stained with carboxy-fluorescein diacetate succinimidyl ester (CFDA SE), after which image processing software was used to determine the area of the confluent cell layer. The 5-year incidence of Nd:YAG laser capsulotomy in this cohort was determined through medical records and by mail or telephone interviews. For statistic analyses Mann–Whitney U-test, Fisher’s exact test and binary logistic regression were used.

Results

Data on treatment/no treatment for PCO was obtained from 270 patients with a median follow-up time of 57 months (range 50–64 months). The three-year cumulative incidence of PCO was 5.2% and the cumulative 5-year incidence was 11.9%. Patients who had undergone Nd:YAG laser capsulotomy were significantly younger (median 71 years) than patients who did not receive treatment for PCO (median 75 years, p = 0.022). Logistic regression demonstrated that apart from younger age, follow-up time and type of intraocular lens (IOL) were associated with risk of PCO, with hydrophilic 1-piece IOLs conferring a higher risk than hydrophobic acrylic 1-piece or 3-piece IOLs (adjusted OR = 9.4, 95% CI 2.5-35.7, p = 0.001). Of the 270 patients from whom information could be retrieved regarding PCO treatment, in vitro cell culture could be established and quantified from 185 patients. No significant difference in cell growth in vitro was shown between patients subsequently requiring/not requiring Nd:YAG laser capsulotomy.

Conclusions

The cumulative 5-year incidence of 11.9% is comparable or slightly higher than reported in other recent studies. The type of IOL was the most important risk factor for PCO in this study, whereas intrinsic proliferative capacity of the individual’s lens epithelial cells seems to be less important for subsequent PCO development.

Posterior capsule opacification and neodymium:YAG rates with 2 single-piece hydrophobic acrylic intraocular lenses: three-year results

PURPOSE

To compare the incidence and intensity of posterior capsule opacification (PCO) between 2 similar 1-piece foldable hydrophobic acrylic intraocular lenses (IOLs) over 3 years.

SETTING

Department of Ophthalmology, Medical University Vienna, Vienna, Austria.

DESIGN

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

METHODS

Patients with bilateral age-related cataract had cataract surgery and implantation of a Tecnis ZCB00 continuous-optic-edge IOL in 1 eye and an Acrysof SA60AT interrupted-optic-edge IOL in the other eye. Postoperative examinations were performed at 6 months and 3 years. Digital retroillumination images were taken of each eye. The amount of PCO (score 0 to 10) was assessed subjectively at the slitlamp and objectively using automated image-analysis software.

RESULTS

The study comprised 54 patients (108 eyes). The mean objective PCO score was 1.3 ± 1.7 (SD) for the continuous-optic-edge IOLs and 0.9 ± 1.3 for the interrupted-optic-edge IOLs (P=.10). Three years postoperatively, a neodymium:YAG (Nd:YAG) capsulotomy was performed in 26.1% of eyes with the continuous-optic-edge IOL and 21.7% with the interrupted-optic-edge IOL (P=.56). There was no significant difference in corrected distance visual acuity, capsulorhexis–IOL overlap, capsule folds, or anterior capsule opacification 3 years after surgery.

CONCLUSIONS

Both IOLs had comparable PCO and Nd:YAG rates 3 years postoperatively. The optimized barrier function of the continuous-optic-edge IOL and the material properties of the interrupted-optic-edge IOL seemingly outbalanced the effect on lens epithelial cell migration and proliferation beneath the optic.

Effect of hydrophobic acrylic versus hydrophilic acrylic intraocular lens on posterior capsule opacification: meta-analysis

PURPOSE

This meta-analysis aims to evaluate the differences in performance of posterior capsular opacification (PCO) between hydrophobic acrylic intraocular lens (IOLs) and hydrophilic acrylic IOLs.

SETTING

Tianjin Medical University, Tianjin Eye Hospital, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin, China.

DESIGN

Systematic review of randomized controlled trials (RCTs) or meta-analysis.

METHODS

An electronic literature search was performed using the PubMed, EMBASE and Cochrane Library database before May in 2013 to identify prospective RCTs comparing hydrophobic acrylic IOLs and hydrophilic acrylic IOLs in patients after phacoemulsification with IOL implantation with a follow-up time of at least 1 year. Pertinent studies were selected by meeting predefined criteria and reviewed systematically by meta-analysis. The PCO scores and YAG capsulotomy rate, as indicator of PCO, were measured and discussed in a meta-analysis. Standardized mean differences (SMD), relative risk ratio (RR), and the pooled estimates were computed according to a random effect model or fixed effect model.

RESULTS

Nine prospective RCTs involving 861 eyes were included in the current meta-analysis. The hydrophobic acrylic IOLs were favored and the pooled SMD of PCO severity was 1.72 (95% confidence interval (CI), 0.20 to 1.23, P = 0.0002) and 1.79 (95% CI, 0.95 to 2.64, P<0.0001) with 1-year follow-up and 2-year follow-up respectively. The pooled RR of Nd:YAG laser capsulotomy rates at postoperative 2-year follow-up was 6.96 (95% CI, 3.69 to 13.11, P<0.00001) comparing hydrophilic acrylic IOLs with hydrophobic acrylic IOLs.

CONCLUSIONS

Compared with hydrophilic acrylic IOLs, the hydrophobic acrylic IOLs showed superior reduction in rates of PCO and laser capsulotomy in 2-year follow-up. More RCTs with standard methods for longer follow-up are needed to validate the association.

Comparison of posterior capsule opacification with hydrophobic acrylic and hydrophilic acrylic intraocular lenses

PURPOSE

To compare posterior capsule opacification (PCO) 3 years postoperatively in contralateral eyes with a single-piece hydrophobic acrylic and 1 of 2 single-piece hydrophilic acrylic intraocular lenses (IOLs) with different configurations.

SETTING

Iladevi Cataract and IOL Research Institute, Ahmedabad, India.

DESIGN

Prospective randomized clinical trial.

METHODS

A hydrophobic Acrysof (hydrophobic group) or a hydrophilic C-flex (hydrophilic group C) or Akreos Adapt IOL (hydrophilic group A) was randomized for implantation in the fellow eye or vice versa of each patient. The Evaluation of Posterior Capsule Opacification (EPCO) area, EPCO score, and neodymium:YAG (Nd:YAG) capsulotomy rates were compared using digital photographs.

RESULTS

The study enrolled 68 patients. Although there was no significant difference at 1 month, the median EPCO score was statistically significantly lower in the hydrophobic group than in hydrophilic group C (P = .00) and hydrophilic group A (P = .000) at 3 years. There were no significant differences in the median EPCO area at 1 month; however, the area was statistically significantly less in the hydrophobic group than in hydrophilic group C and hydrophilic group A at 3 years (both P = .000). Four (12.9%) of 31 eyes in hydrophilic group C and 5 (16%) of 31 eyes in hydrophilic group A required an Nd:YAG capsulotomy; no eye in the hydrophobic group required a capsulotomy (P = .04 and P = .02, respectively).

CONCLUSION

Posterior capsule opacification was significantly less with the Acrysof hydrophobic acrylic IOL at 3 years.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Pathology of 219 human cadaver eyes with 1-piece or 3-piece hydrophobic acrylic intraocular lenses: capsular bag opacification and sites of square-edged barrier breach

PURPOSE

To assess capsular bag opacification and sites of initial posterior capsule opacification (PCO) in human cadaver eyes with square-edged 1-piece or 3-piece hydrophobic acrylic intraocular lenses (IOLs).

SETTING

John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

DESIGN

Experimental study.

METHODS

Eyes were immersed in 10% formalin after enucleation and had anterior segment scanning with very-high-frequency ultrasound (Artemis). After the eyes were sectioned at the equator, gross examination of the anterior segment was performed from the posterior aspect to assess capsular bag opacification, anterior capsule coverage of the IOL edge, and IOL fixation. Selected eyes had histopathologic examination.

RESULTS

One hundred nineteen eyes with 1-piece IOLs and 100 with 3-piece IOLs were included in the analyses of capsular bag opacification. There was no difference in central (P=.29) or peripheral (P=.76) PCO. In 63 of 84 eyes with a 1-piece IOL and peripheral PCO, the optic-haptic junction was the site of initiation. In eyes with a 3-piece IOL, initial peripheral PCO was observed at nearly the same rate whether there was full 360-degree anterior capsulorhexis overlap of the optic or no overlap (P=.13). In the latter, the site of PCO initiation was in areas lacking capsulorhexis coverage in 46% of eyes.

CONCLUSIONS

There was no difference in central or peripheral PCO between 1-piece and 3-piece hydrophobic acrylic IOLs. With 1-piece IOLs, PCO tended to start at the optic-haptic junctions. With 3-piece IOLs, full anterior capsule coverage did not produce a statistically significant benefit with respect to PCO prevention.

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.

Interventions for preventing posterior capsule opacification

BACKGROUND

Posterior capsule opacification (PCO) remains the most common long-term complication after cataract surgery. It can be treated by Nd:YAG laser capsulotomy, however this may lead to other complications and laser treatment is not available in large parts of the developing world. Therefore, many studies try to find factors influencing the development of PCO.

OBJECTIVES

To summarise the effects of different interventions to inhibit PCO. These include modifications of surgical technique and intraocular lens (IOL) design, implantation of additional devices and pharmacological interventions.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, EMBASE, LILACS in March 2009 and reference lists of identified trial reports.

SELECTION CRITERIA

We included only prospective, randomised and controlled trials with a follow-up time of at least 12 months. Interventions included modifications in surgical technique explicitly to inhibit PCO, modifications in IOL design (material and geometry), implantation of additional devices and pharmacological therapy compared to each other, placebo or standard treatment.

DATA COLLECTION AND ANALYSIS

We extracted data and entered it into RevMan. We compared visual acuity data, PCO scores and YAG capsulotomy rates and performed a meta-analysis when possible.

MAIN RESULTS

Sixty six studies were included in the review. The review was divided into three parts. 1. Influence of IOL optic material on the development of PCO. There was no significant difference in PCO development between the different IOL materials (PMMA, hydrogel, hydrophobic acrylic, silicone) although hydrogel IOLs tend to have higher PCO scores and silicone IOLs lower PCO scores than the other materials. 2. Influence of IOL optic design on the development of PCO. There was a significantly lower PCO score (-8.65 (-10.72 to -6.59), scale 0 to 100) and YAG rate (0.19 (0.11 to 0.35)) in sharp edged than in round edged IOLs, however not between 1-piece and 3-piece IOLs. 3. Influence of surgical technique and drugs on the development of PCO. There was no significant difference between different types of intraoperative/postoperative anti-inflammatory treatment except for treatment with an immunotoxin (MDX-A) which led to a significantly lower PCO rate.

AUTHORS' CONCLUSIONS

Due to the highly significant difference between round and sharp edged IOL optics, IOLs with sharp (posterior) optic edges should be preferred. There is no clear difference between optic materials. The choice of postoperative anti-inflammatory treatment does not seem to influence PCO development.

Clinical consequences of acrylic intraocular lens material and design: Nd:YAG-laser capsulotomy rates in 3 x 300 eyes 5 years after phacoemulsification

Background/aims

To investigate the incidence of Nd:YAG-laser treatment for posterior capsular opacification (PCO) over a period of 5 years from phacoemulsification in an unselected population, comparing outcomes for three acrylic intraocular lenses (IOLs).

Methods

Retrospective longitudinal cohort study comprising 900 eyes. Three subgroups of 300 eyes, receiving the AR40, AR40e (Abbott Medical Optics, Santa Ana, California), or BL27 (Bausch & Lomb, Rochester, New York) IOL respectively, were compared. Data on patient age, gender, IOL type, dates of cataract surgery, Nd:YAG-laser treatment and/or death, and visual acuities before/after cataract surgery/Nd:YAG-laser treatment were collected from five sources: cataract operation register, patient administration system, quality control system for cataract operations, Nd:YAG-laser treatment register and clinical patient records.

Results

216 eyes (24%) received Nd:YAG-laser treatment over a 5-year period. Statistically significant differences (p<0.001, χ² test) were found between treatment rates for the three IOLs: AR40 73 eyes (24%), BL27 91 eyes (30%) and AR40e 52 eyes (17%). Eyes of patients who died during the follow-up period had fewer treatments (23/266, 8.6%) than eyes of patients living (193/634, 30%) at the end of the follow-up period.

Conclusion

In comparison with a hydrophobic acrylic IOL with sharp posterior optic edge, a hydrophilic acrylic IOL was associated with almost twice the number of Nd:YAG-laser treatments over the 5-year period. The results are useful for discussing the economic long-term consequences of choosing an IOL with a design that makes PCO development more or less likely. Caution is advised when applying data from post-mortem PCO studies on living populations.

Evaluating and defining the sharpness of intraocular lenses: microedge structure of commercially available square-edged hydrophilic intraocular lenses

PURPOSE

To evaluate the microstructure of the edges of currently available hydrophilic acrylic intraocular lenses (IOLs) in terms of their deviation from an "ideal" square as a follow-up of preliminary in vitro studies of experimental poly(methyl methacrylate) IOLs and commercially available foldable hydrophobic IOLs.

SETTING

Berlin Eye Research Institute, Berlin, Germany.

METHODS

Twenty-four designs of hydrophilic acrylic IOLs were used in this study. For each design, a +20.0 diopter (D) IOL and a +0.0 D IOL (or the lowest available plus dioptric power) were evaluated. The IOL edge was imaged under low-vacuum (0.7 torr), high-magnification scanning electron microscopy (SEM) using an environmental microscope and standardized technique. The photographs were imported to a digital computer program, and the area above the posterior-lateral edge, representing the deviation from a perfect square, was measured in square microns.

RESULTS

Currently available hydrophilic acrylic IOLs labeled as square edged had an area of deviation from a perfect square ranging from 60.84 to 871.51 microm(2) for the +20.0 D IOLs and from 35.52 to 826.55 microm(2) for the low-diopter IOLs. Although some differences in edge finishing between the IOLs analyzed were observed, edge surfaces of hydrophilic acrylic IOLs appeared overall smooth under environmental SEM.

CONCLUSIONS

Analysis of the microstructure of the optic edge of currently available square-edged hydrophilic acrylic IOLs showed a large variation of the deviation area from a perfect square.

Prediction of refractive error in combined vitrectomy and cataract surgery with one-piece acrylic intraocular lens

Purpose

To compare the predicted and actual refractive errors of hydrophilic, one-piece, C-flex®570C (C-flex) intraocular lens (IOL) implantation in simultaneous vitrectomy and lens extraction in various conditions.

Methods

One hundred fifty-nine eyes of patients who had lens extraction between March 2004 and September 2005 were enrolled in a retrospective study. Group 1 had lens extraction and IOL implantation, and Group 2 had lens extraction and IOL implantation with vitrectomy. IOL calculation was done with axial length and keratometry measurements. The actual and predicted refractive errors were compared at 1 and 6 months postoperatively. The factors influencing the postoperative refractive outcomes were analyzed.

Results

The mean refractive predictive error (i.e., the actual minus predicted spherical equivalent) was +0.19±0.39 D (Diopter) and -0.26±0.45 D at 1 and 6 months postoperatively (all: p<0.001) in group 1, and -0.22±0.39 D and -0.06±0.62 D at 1 and 6 months postoperatively (p=0.013, p=0.399 respectively). In group 2, all surgical factors related to refractive errors were not statistically significant (all: p>0.05).

Conclusions

Refractive errors in combined surgery showed myopic shift of -0.50 D and -0.32 D at 1 and 6 months postoperatively compared with C-flex IOL implantation alone. With the hyperopic tendency of IOL and myopic tendency of vitrectomy, the combined surgery made postoperative refractive errors near emmetropia.

Biocompatibility of intraocular lens materials

PURPOSE OF REVIEW

To provide an update on currently available materials used in the manufacture of intraocular lenses, as well as new materials under development, especially with regard to their uveal and capsular biocompatibility.

RECENT FINDINGS

The biocompatibility of intraocular lens materials should be assessed in terms of uveal biocompatibility, related to the inflammatory foreign-body reaction of the eye against the implant, as well as in terms of capsular biocompatibility, determined by the relationship of the intraocular lens with remaining lens epithelial cells within the capsular bag. This situation may result in different entities, e.g. anterior capsule opacification, interlenticular opacification (between piggyback intraocular lenses), posterior capsule opacification and lens epithelial cell ongrowth. Reports on intraocular lens opacification suggest that the potential to calcify should also be taken into consideration when evaluating the long-term biocompatibility of a new material.

SUMMARY

Intraocular lenses are being progressively implanted in much earlier stages of life (refractive lens exchange, pediatric implantation) and are expected to remain in the intraocular environment for many decades. Materials used in intraocular lens manufacture should, therefore, insure long-term uveal and capsular biocompatibility, as well as ultimate transparency after implantation.

[Toric IOLs after cataract surgery and refractive lens exchange]

Patients with astigmatism (e.g. regular or keratoplasty-induced astigmatism) who undergo cataract surgery or refractive lens exchange with a standard monofocal IOL are often disappointed. Toric IOLs (T-IOLs) are, therefore, an excellent alternative for this condition. T-IOLs are now available from companies such as Alcon, Acri, Tec, Humanoptics, Wavelight, Rayner and Staar. Apart from Alcon and Staar who only produce T-IOLs with a fixed torus, all these produce customised lenses. The calculations needed for production of the T-IOLs are generally done by the companies and are based on the corneal astigmatism. T-IOLs have shown good rotational stability and good functional results. Corneal astigmatism can still be measured postoperatively, as it is corrected inside the eye. The referring ophthalmologist should exercise discretion when prescribing spectacles after surgery of this kind.

Rate of posterior capsule opacification in eyes with the Akreos intraocular lens

PURPOSE

To determine the rate of posterior capsule opacification (PCO) in eyes with an Akreos Adapt or Akreos Fit intraocular lens (IOL) (Bausch & Lomb) over a minimum follow-up of 18 months.

SETTING

Department of Ophthalmology, Worthing and Southlands Hospital NHS Trust, Worthing, United Kingdom.

METHOD

This was a retrospective analysis of 102 patients who had uneventful phacoemulsification with implantation of an Akreos Adapt IOL or Akreos Fit IOL from September 2001 to May 2004. Patients from a single surgeon's operating list were recruited into the study. Exclusion criteria included posterior subcapsular cataract, history of uveitis, diabetic retinopathy, glaucoma, and age-related macular degeneration. The protocol included the determination of logMAR best corrected visual acuity (BCVA) and PCO scoring using the Evaluation of Posterior Capsular Opacification System (EPCO 2000) by digital photography of the posterior capsule. The number of patients having a neodymium:YAG (Nd:YAG) capsulotomy was also recorded.

RESULTS

The mean follow-up was 30 months +/- 10.3 (SD). The mean BCVA was 20/32 (0.2 logMAR). The mean EPCO score at the central 6.0 mm of the posterior capsule was 0.39 +/- 0.53 and at the central 3.0 mm, 0.18 +/- 0.40. The Nd:YAG capsulotomy rate was 8.8%.

CONCLUSIONS

All patients had stable visual acuity with low rates of PCO 2.5 years after surgery. The PCO rate with the Akreos IOL was similar to that with other acrylic IOLs reported in the literature.