Visual significance of glistenings seen in the AcrySof intraocular lens

Stainability of Acrylic Intraocular Lens With Brilliant Blue G: An In Vitro Study

PURPOSE

To evaluate the stainability of several acrylic intraocular lens (IOLs) with Brilliant Blue G (BBG) in vitro.

DESIGN

Clinically relevant, laboratory, experimental study.

METHODS

LS313MF15 as a hydrophilic acrylic IOL and X-70, W60R, CP2.2R, YP2.2R, XC1, and XY1 as hydrophobic acrylic IOLs were included in this study. Prepared acrylic IOLs were evaluated for staining via immersion for different periods in BBG solution with adjusted concentrations. In cases where IOLs were stained blue, the sustained release of BBG and IOL cross-sectional images were evaluated, as well as changes in the optical properties of the IOLs via spectrophotometry.

RESULTS

All acrylic IOLs were stained with BBG in a BBG concentration- and staining time-dependent manner, with almost no sustained release of BBG observed. Lenses with a higher water content exhibited more pronounced staining, and BBG penetrated into the IOLs. A decrease in light transmittance with a peak wavelength of 610 to 620 nm was observed in blue-stained IOLs. LS313MF15 was markedly blue stained even with a short period of staining.

CONCLUSIONS

Any acrylic IOL can be stained with BBG, but hydrophilic IOLs are particularly susceptible to blue staining. Precautions should be taken in surgeries requiring the use of BBG staining, and efforts should be made to ensure that BBG components are sufficiently washed out intraoperatively.

The effect of hypotensive drugs on intraocular lenses clarity

OBJECTIVES

To assess the effect of hypotensive drugs on light absorbance, discoloration, opacification and precipitate formation of IOLs.

METHODS

In this laboratory study, four types of IOLs (two hydrophilic-acrylic-L1 and L2, and two hydrophobic-acrylic-B1 and B2) were soaked in solutions containing Timolol-maleate 0.5%, Dorzolamide 2%, Brimonidine-tartrate 0.2%, Latanoprost 0.005%, Brimonidine-tartrate/Timolol-maleate 0.2%/0.5% and Dorzolamide/Timolol-maleate 2%/0.5%. Non-treated IOLs and IOLs soaked in balanced salt solution (BSS) served as controls. All Treated lenses were sealed in containers and placed in an oven at 82 degrees Celsius for 120 days. Each IOL was examined using four different techniques: light microscopy imaging, light absorbance measurements at 550 nanometers through the optic's center, assessment of by a scanning electron microscope (SEM), and energy dispersive Xray spectrometry (EDX).

RESULTS

Ninety-eight IOLs were included. All BSS-soaked IOLs appeared clear with no significant discoloration or precipitate-formation. Light absorbance in these lenses was comparable to that of non-soaked, non-heated IOLs. No calcium or phosphate were detected in either of these groups. Light absorbance differed significantly between the four treated IOL types. The drops most affecting light absorbance differed between IOLs. Gross examination revealed brown and yellow discoloration of all IOLs soaked in Dorzolamide and Brimonidine-tartrate solutions, respectively. SEM demonstrated precipitates that differed in size, morphology and distribution, between different IOL-solution combinations. EDX's demonstrated the presence calcium and phosphor in the majority of precipitates and the presence of sulfur in brown discolored IOLs.

CONCLUSIONS

In vitro, interactions between hypotensive drugs and IOLs induce changes in light absorbance, discoloration and precipitate formation.

Specifying Risk of Intraocular Lens Opacification After Endothelial Keratoplasty for Different Intraocular Lens Models: A Retrospective Monocentric Cohort Study

PURPOSE

The aims of this study were to calculate the specific risk of opacification for different intraocular lens (IOL) models and to determine whether differences exist, even between lenses made of similar acrylic materials.

METHODS

This is a retrospective cohort study of all patients who underwent endothelial keratoplasty (EK), either after or in conjunction with cataract surgery, from June 2009 to October 2020 at Fundación Jiménez Díaz Hospital.

RESULTS

Three hundred seventy-two eyes of 308 patients with a median follow-up of 856 days [interquartile range (IQR): 384-1570] were included, of which 128 IOLs were hydrophobic, 120 hydrophilic, and 124 unknown. 12.9% of IOLs opacified after a median of 466 days (IQR: 255-743). Visual acuity (VA) was significantly lower in the opacified IOL group [0.51 (IQR: 0.36-1.13)] compared with the nonopacified group [0.22 (IQR: 0.11-0.65)] ( P < 0.001). IOL explantation and exchange was performed in 10 eyes, in which VA improved markedly, from 1.75 (IQR: 0.99-3.00) to 0.60 (IQR: 0.36-0.86) ( P = 0.004). IOL material and opacification events were not independent ( P < 0.001). Significant differences were found between the Akreos ADAPT AO and MI60P models and the Asphina 409M model ( P = 0.022). No significant differences were found in the opacification ratio for hydrophilic IOLs in the clinical diagnosis ( P = 0.11), the type of EK ( P = 0.25), the rebubbling rate ( P = 0.44), or the tamponade used ( P = 0.36).

CONCLUSIONS

Hydrophilic lenses should be avoided in patients at risk of requiring EK. It is important to know the probability of opacification of each IOL model to balance risk and benefits when planning an EK procedure because not all lenses opacify equally. Opacification is an unwanted event with a negative impact on VA, making IOL explantation and exchange the only viable treatment, although one that is not without risks.

Comparison Between L-312 Hydrophobic-Hydrophilic Acrylate and US-860 UV Hydrophilic Acrylate IOL Opacification Characteristic

Objective

To compare opacity characteristics of US-860 UV and L-312 IOL, and report the phenomenon of glistenings in hydrophobic-hydrophilic acrylic IOLs.

Setting

Qingdao Eye Hospital.

Design

Experimental study.

Methods

Four medical records (4 eyes) of patients with L-312 or US-860 UV IOL opacification reporting decreased or lost vision who underwent IOL explanation between 2019 and 2021 were reviewed. Explanted IOLs were analyzed by slit-lamp examination, confocal microscopy, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) at Qingdao Eye Hospital and Qingdao university of science and technology.

Results

The 4 explanted IOLs were represented by 2 hydrophilic acrylic designs. The preoperative mean corrected distance visual acuity changed from 1.84 ± 1.09 logarithm of the minimum angle of resolution (log MAR) to 0.20 ± 0.03 log MAR postoperatively except case 3. The mean interval of the L-312 IOL was 56.67 ± 14.19 months (range 44 to 72 months), and the interval of the US-860 UV IOL was 27 months. Morphological findings were surface, subsurface calcifications of the US-860 UV IOL material, and the optical region of L-312 IOLs are teeming with a great number of vacuoles by light microscope, scanning electron microscope and Energy Dispersive X-ray Spectral.

Conclusion

The cause of US-860 UV opacification was primary calcification, and vacuoles resulted in L-312 IOL opacification.

Clinical Features of Patients with Opacification of Hydrophilic Acrylic Intraocular Lens in Neovascular Glaucoma

Purpose: To report the clinical features of patients with opacification of hydrophilic acrylic intraocular lens (IOL) after cataract surgery in neovascular glaucoma.Methods: This retrospective case series included 11 eyes of 10 patients with IOL opacification and neovascular glaucoma (NVG) between January 2006 and December 2010. We included and analyzed cases with opacification of hydrophilic acrylic IOL. An IOL exchange was performed in three cases, and the explanted IOLs were examined grossly and evaluated by light microscopy. Sagittal sections of the optics of the IOLs were evaluated by Von Kossa staining, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX).Results: All 11 eyes of 10 patients were implanted with hydrophilic acrylic IOLs. In addition, there were no cases of hydrophobic acrylic IOL opacification. Nine patients of the 10 patients had diabetic retinopathy and one patient had central retinal artery occlusion. The mean period of IOL opacification after IOL implantation was 19.45 ± 8.52 months and the mean period of IOL opacification after the occurrence of NVG was 14.37 ± 8.51 months. The deposits of the explanted IOLs were shown to consist of calcium by von Kossa staining. The explanted IOLs showed fine whitish irregular granular deposits on the entire anterior surface of the optics by SEM and the presence of calcium deposition was confirmed by EDX analysis.Conclusions: Care is required when using hydrophilic acrylic IOLs in patients with risk of neovascular glaucoma, such as those with diabetic retinopathy or central retinal artery occlusion.

Comparative analysis of in vitro accelerated glistening formation in foldable hydrophobic intraocular lenses

PURPOSE

To analyse and compare the propensity to form glistenings in 4 different types of hydrophobic acrylic intraocular lenses (IOLs): Alcon AcrySof ® MA60AC, HOYA iSert® PC-60AD, Bausch&Lomb enVista, and Kowa Avansee™ PU6A.

METHODS

We used an accelerated laboratory method to create glistenings. IOLs were first immersed in saline at 45 °C for 24 h and then at 37 °C for 2.5 h. Microvacuole (MV) density and size were documented and calculated using an image analysis program.

RESULTS

Median density of glistenings [MV/mm2] for Alcon AcrySof ® MA60AC was 623 (range 507-804), for HOYA iSert® PC-60AD 1358 (range 684-2699), for Bausch&Lomb enVista 2 (range 1-2), and for Kowa Avansee™ PU6A 1 (range 1-4). The prevailing MV size was: 0-5 µm for Hoya IOLs, 5-10 µm for Alcon IOLs, 20-50 µm for Bausch&Lomb IOLs, and 5-50 µm for Kowa IOLs.

CONCLUSIONS

Glistenings could be induced in all studied IOLs using the accelerated laboratory method. The Alcon AcrySof ® MA60AC and HOYA iSert® PC-60AD IOLs showed MV of high density, while the glistenings in the Hoya IOLs were smaller in size compared to the Alcon IOLs. The MV density was minimal in the Bausch&Lomb enVista and Kowa Avansee™ PU6A IOLs. The propensity of the Alcon AcrySof ® MA60AC IOLs to form glistenings in vitro correlated with the findings of clinical results that are already published.

Microscopic Characteristics of Late Intraocular Lens Opacifications

CONTEXT.—

The increases in overall life expectancy and in lens surgeries performed on younger patients have resulted in a significant increase in the anticipated duration of artificial intraocular lenses (IOLs) in the eye. Thus, the physicochemical properties of the IOL become a critical issue, and several types of postoperative IOL opacifications have been reported.

OBJECTIVE.—

To describe the microscopic characteristics of opacified IOLs. Glistenings and subsurface nanoglistenings are fluid-related phenomena developing mainly in hydrophobic acrylic IOLs and are associated with aqueous influx into the IOL matrix. Calcification presents in hydrophilic acrylic or silicone IOLs as deposits of hydroxyapatite or other phases of calcium. Snowflake degeneration is less common, and it manifests in older polymethyl methacrylate IOLs.

DATA SOURCES.—

PubMed and ScienceDirect databases were searched for the following keywords: intraocular lens, IOL, cataract surgery, phacoemulsification, opacification, glistening, subsurface nanoglistenings, calcification, snowflake degeneration. English-language articles published up to October 15, 2019 were included in the study. The manuscript contains mainly a literature review; however, it was supplemented with original investigations from the David J. Apple International Laboratory for Ocular Pathology.

CONCLUSIONS.—

Glistenings and subsurface nanoglistenings should be evaluated in a hydrated state and at room temperature; they manifest as microvacuoles sized from 1.0 to greater than 25.0 μm and less than 200 nm, respectively. Calcification deposits are situated on or underneath the surface of the IOL and can be stained with a 1% alizarin red solution or with the von Kossa method. Snowflake degeneration manifests as "particles" or "crystals," causing whitish IOL discoloration. Scanning electron microscopy or energy dispersive X-ray spectroscopy may improve the diagnostic accuracy.

Foldable Glistening-Free Acrylic Intraocular Lens Biomaterials with Dual-Side Heterogeneous Surface Modification for Postoperative Endophthalmitis and Posterior Capsule Opacification Prophylaxis

Hydrophobic acrylic intraocular lenses (IOLs) are widely used in cataract treatment for posterior capsule opacification (PCO) prophylaxis. However, undesired glistening and postoperative endophthalmitis are two major potential risks. Hence, a series of poly(2-phenoxyethyl methacrylate-co-2-phenoxyethyl acrylate-co-2-ethylhexyl methacrylate) (PPPE) acrylic IOL materials were synthesized for "glistening-free" optimization. The selected PPPE with 2% 2-ethylhexyl methacrylate showed excellent optical, foldable, and thermomechanical properties. The anterior surface of PPPE was coated with polydopamine followed by gentamycin conjugation (PDA/GS). It inhibited bacterial adhesion by 74% and decreased the biofilm thickness by 87%. In inflammatory mimicking conditions, bacterial proliferation was restrained, with acidic-dependent GS release behavior. The surface of PPPE toward the posterior capsule remained hydrophobic. It was conducive to human lens epithelial cell adhesion, collagen IV and fibronectin adsorption, and the following "sealed sandwich structure" formation. In summary, the PPPE with a dual-side heterogeneous surface displayed good application prospects in postoperative endophthalmitis and PCO prevention.

Light scattering in intraocular lenses explanted 15 to 40 years after surgery

The optical quality of intraocular lenses (IOLs) of different materials that have been implanted from 16 to 44 years in human eyes was studied. The IOLs were explanted due to other causes than loss of transparency. The scattered light from the IOLs was assessed in two angular regimes by using dark field images (for wide angles) and the optical integration method (for narrower angles). No evident differences were found in the scattering intensities processed from the dark images. The explanted lenses presented slightly increased amounts of straylight between 1 and 5.1° when compared to a reference new unused lens.

[Opacification of Intraocular Lenses]

The spectrum of complications in the use of intraocular lenses (IOL) is different today from at the time of their introduction. Opacities in the IOL material are increasingly described in the literature as a reason for IOL explantation. This paper provides an overview of the different forms of IOL material opacities. Currently relevant forms of IOL material opacities and their effects on optical quality are summarized. The main reason for opacification in hydrophilic IOLs is calcification, whereas in hydrophobic IOLs it is mainly the formation of so-called glistenings that is reported. Most material opacities affect various optical parameters and lead to increased intraocular straylight. In case of a disturbing material opacification, the only therapeutic option is to replace the opacified IOL.

Eintrübung von Intraokularlinsen

Das Spektrum an Komplikationen und die Explantationsgründe bei der Verwendung von Intraokularlinsen (IOL) haben sich durch die Weiterentwicklung der Kataraktchirurgie verändert. Eintrübungen des Materials beeinflussen dabei unterschiedlich stark die optische Qualität. Im Fall einer störenden Eintrübung des Materials ist auch heute noch – trotz aller Fortschritte auf dem Gebiet der IOL-Materialien – ein Austausch der IOL die einzige Behandlungsoption.

Intraocular lenses as drug delivery devices

Cataract surgery is one of the most common and safe surgical procedures nowadays. However, it is not free of risks as endophthalmitis, ocular inflammation and posterior capsule opacification (PCO) can appear as post-surgery complications. The usual eye drop therapy used as prophylaxis for the former two complications has limited bioavailability. In turn, the prevention of PCO involves an adequate surgical technique and a careful choice of intraocular lens (IOL) design and material. Also, different drugs have been tested to reduce incidence of PCO, but no prophylaxis demonstrated to be completely effective. In the past few years, IOLs have been proposed as drug delivery devices to replace or/assist the usual eye drop therapy in the post-operatory period. The great advantage of drug loaded IOLs would be to ensure a continuous drug delivery, independent of patient's compliance without requiring any further action besides IOL implantation. The biggest challenge of drug loaded IOLs production is to achieve a controlled and extended release that meet therapeutic needs without inducing toxicity to the surrounding ocular tissues or affecting the physical properties of the lens. This review starts by addressing the possible complications after cataract surgery, as well as the most commonly adopted prophylaxis for each of them. The various types of IOLs are described and their main advantages/disadvantages are discussed. The different strategies pursued to incorporate drugs into the IOLs and control their release, which include soaking the IOL in the drugs solution, supercritical impregnation, surface modifications, and attachment of drug reservoirs to the IOL, among others, are reported. For each strategy, a summary of the publications is presented, which includes the target complication, the types and amounts of released drugs and the IOL materials. A brief description of each individual study is given afterwards. Optimization of drug loaded IOLs through mathematical modelling and possible issues raised by their sterilization are also tackled. At the end, the future commercialization of drug loaded IOLs is commented.

In-vitro glistening formation in six different foldable hydrophobic intraocular lenses

Background

Glistenings describe small, refractile microvacuoles that may arise within the intraocular lens (IOL) material and reduce the patients’ quality of vision. Lenses composed of hydrophobic acrylic material are particularly affected by glistening formation. In this study, we compared the tendency of glistening formation in six different types of hydrophobic acrylic intraocular lenses (IOLs).

Methods

We used a well-established accelerated laboratory method to develop glistenings in the following IOLs: Vivinex XY1 (Hoya), AcrySof SN60WF (Alcon), Tecnis ZCB00 (AMO), Avansee PN6A (Kowa), Aktis SP NS-60YG (Nidek), and CT Lucia 601P (Zeiss). IOLs were first immersed in saline at 45 °C for 24 h and then at 37 °C for 2.5 h in a water bath. Microvacuole (MV) density and size (Miyata grading) were documented and calculated using an image analysis program.

Results

The mean glistening density [MV/mm²] and mean Miyata grading (in brackets) were: Vivinex: 11.6 ± 5.7 (0), SN60WF: 264.4 ± 110.3 (2.6), Tecnis: 6.0 ± 2.8 (0), Avansee: 2.2 ± 0.7 (0), Aktis: 851.4 ± 59.4 (3+) and CT Lucia: 71.0 ± 71.6 (1).

Conclusions

While all tested IOLs showed glistenings with the accelerated laboratory method, the Aktis and SN60WF showed the highest microvacuole density, followed by the CT Lucia. In comparison, the Vivinex, Tecnis, and Avansee IOLs showed far fewer number of glistenings.

Quantification of the In Vitro Predisposition to Glistening Formation in One Manufacturer's Acrylic Intraocular Lenses Made in Different Decades

Introduction

Foldable hydrophobic acrylic intraocular lenses (IOLs) are prone to develop a long-term postoperative material change called glistenings. The aim of this study was to investigate the changes in the predisposition for glistening formation in one type of hydrophobic acrylic IOL material from its introduction to the present day.

Methods

In a laboratory setup, an in vitro model was used to induce glistenings in hydrophobic acrylic IOLs manufactured by one company (Alcon, Fort Worth, TX, USA) in different years: 23 1990s-manufacture hydrophobic acrylic three-piece IOLs (MA30BA/MA60AC) that were explanted in 1996 and 1997, and five of each of the newer AcrySof IOL models (MA60AC, SA60AT, TFNT00 and SN60WF) from 2014 to 2017. Furthermore, five Clareon (SY60WF) IOLs were put through the same accelerated aging procedure. The number of microvacuoles per square millimeter (MV/mm²) was determined in the central part of each IOL optic and compared between the groups.

Results

The mean number of MV was highest in the 1990s-manufacture Alcon acrylic IOLs, with 1289 (± 738) MV/mm². The number decreased to 650 (± 101), 192 (± 105), 175 (± 112) and 47 (± 26) for MA60AC, SA60AT, TFNT00 and SN60WF, respectively. The lowest count was obtained in the Clareon group, with 1 (± 1) MV/mm².

Conclusions

A high number of glistenings was induced in the explanted IOLs from the 1990s. The propensity for glistening formation decreased considerably after that decade and now in current use. Even though in vitro glistening formation in today’s AcrySof material was low, the Clareon material was essentially glistenings-free.

A review of late intraocular lens opacifications

PURPOSE OF REVIEW

Phacoemulsification cataract surgery is one of the most commonly performed surgical procedure worldwide. In the majority of cases, intraocular lenses (IOLs) are implanted. Due to the increasing life expectancy and the fact that cataract surgery is performed in earlier stages, the anticipated IOL duration in the eye has increased over the last decades. The aim of this study was to review the types and describe the characteristics of late intraocular lens opacifications.

RECENT FINDINGS

Calcification was the most commonly reported type of opacification in hydrophilic IOLs; it usually negatively impacted the visual function and required IOL explantation. Glistening manifested in hydrophobic acrylic lenses and was frequent in some IOL models. In most cases glistening and subsurface nanoglistenigs do not lead to a decline in visual acuity or require IOL exchange. Current studies indicate that fluid-related phenomena may induce straylight, leading to a decrease of comfort and quality of vision.

SUMMARY

Several reports on late IOL opacifications have been published in recent years. In some cases, particularly in glistening, the development of the opacifications might be related to IOL aging. The influence of the fluid-related microvacuoles on the quality of vision requires further research.

[Opacification of intraocular lenses: laboratory and clinical findings]

Hintergrund

Das Spektrum der Komplikationen beim Einsatz von Intraokularlinsen (IOL) ist heute ein anderes als zur Zeit ihrer Einführung. Trübungen im IOL-Material werden vermehrt als Explantationsgrund in der Literatur beschrieben.

Ziel der Arbeit

Diese Arbeit soll einen Überblick über die verschiedenen Formen von IOL-Materialeintrübungen geben.

Material und Methoden

Die heute relevanten Formen von IOL-Materialeintrübungen und deren Auswirkungen auf die optische Abbildungsqualität wurden zusammengestellt.

Ergebnisse und Diskussion

Als Grund für eine Eintrübung steht bei hydrophilen IOL die Kalzifikation im Vordergrund, während bei hydrophoben IOL v. a. über die Entstehung sog. „Glistenings“ berichtet wird. Die meisten Materialeintrübungen beeinflussen verschiedene optische Parameter und führen zu einem erhöhten intraokularen Streulicht. Im Falle einer störenden Materialeintrübung besteht die einzige Therapieoption in einem Austausch der eingetrübten IOL.

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.

The assessment of the impact of glistening on visual performance in relation to tear film quality

Background

The aim of our case control study was to evaluate the impact of glistening and tear film quality on visual performance after implantation of two different hydrophobic acrylic intraocular lenses (IOLs).

Materials and methods

In our retrospective study we included cataract patients operated between January 1, 2011 and December 31, 2012, with follow-up controls between January 2016 and December 2019. Z-Flex 860FAB (Medicontur) and AcrySof IQ SN60WF (Alcon) monofocal IOLs were implanted during standard phacoemulsification. Best corrected distance visual acuity (BCDVA) and contrast sensitivity were monitored over the post-operative period of up to 6 years. Glistening was evaluated semi-quantitatively with slit-lamp biomicroscopy and quantitatively using Pentacam HR (Oculus). Using HD Analyzer OQAS (Visiometrics), total intraocular light diffusion was interpreted with the objective scatter index (OSI) and tear film quality was evaluated with the tear film related objective scatter index (TF-OSI).

Results

26 eyes implanted with the Z-Flex and 25 eyes with the AcrySof IQ IOLs were included in the analysis. The slit-lamp evaluation of patients with the Z-Flex IOL (0.57 ± 0.60) revealed significantly less glistening (p<0.0001), compared to the AcrySof IQ group (1.82 ± 0.90), and these observations were confirmed by the Pentacam HR analyses, as well (Z-Flex group: 35.1 ± 1.63, Acrysof IQ: 39.6 ± 3.69, p<0.0001). TF-OSI differed between the two sets of patients remarkably (1.53 ± 1.03 vs. 2.51 ± 1.76 for AcrySof IQ and Z-Flex groups, respectively, p = 0.043). Both groups of patients provided similar results of BCDVA and contrast sensitivity.

Conclusion

Glistening and tear film quality both contribute to visual performance outcomes after cataract surgery. In our study the advantage of less glistening in the Z-Flex IOL might have been masked by the adverse effects of the more pronounced tear film insufficiency of these patients, compared to the AcrySof IQ group. Among other factors, tear film quality should also be taken into consideration when comparing the impact of glistening on visual quality of patients implanted with different IOLs.

Comparison of glistenings formation and their effect on forward light scatter between the Acrysof SN60WF and Eternity Natural Uni NW-60 intraocular lenses

Aims

To compare the characteristics of glistenings and forward light scatter between the Alcon Acrysof SN60WF and Santen Eternity Natural Uni NW-60 intraocular lenses (IOLs).

Methods

Five Acrysof SN60WF and five Eternity Natural Uni NW-60 IOLs were studied. All IOLs were single piece blue blockers with the same dioptric power (20D) and optic diameter (6.0 mm). Glistenings were induced by a thermal accelerated ageing process. Glistenings were objectively quantified using bespoke image processing software. The angular distribution of forward light scatter was measured using an optical bench system and the straylight parameter calculated from the light scatter function.

Results

The median increase in the number of glistenings was 15 and 525 for the Eternity and Acrysof IOLs, respectively, which was statistically significantly different (p=0.012). Median glistenings diameter was 23.8 μm (Acrysof) and 32.8 μm (Eternity). Four (80%) of the Acrysof lenses had straylight values higher than a 20-year-old CIE standard glare observer and in two cases the straylight exceeded that of the 70-year-old CIE standard glare observer. None of the Eternity lenses had straylight values that exceeded the value for the 20-year-old CIE standard glare observer.

Conclusions

The Eternity Natural Uni NW-60 IOLs resisted the induction of glistenings more than the Acrysof SN60WF IOLs. Although the Acrysof IOLs developed smaller glistenings than the Eternity IOLs, there were sufficient numbers to produce a higher straylight parameter.

An evaluation of glistening and stability of intraocular lens material manufactured by different methods

PURPOSE

To evaluate glistening and long-term stability of five commercially available intraocular lenses.

METHODS

This experimental study evaluated the SN60WF (Alcon), XY1 (Hoya), NS-60YG (NIDEK), ZCB00V (Johnson & Johnson Vision) and AN6KA (Kowa) intraocular lenses. To generate glistenings, intraocular lenses were immersed in physiological saline at 50°C for 2 h, then left in situ at 35°C and removed at regular intervals over 24 h. Stability of the intraocular lens material was assessed by immersing intraocular lenses into vials of purified water placed at 100°C for 115 days, which simulated 20-year ageing. Gas chromatography-mass spectrometry was used to detect leached compounds.

RESULTS

Almost no glistenings were observed for the AN6KA. Glistenings were observed in the remaining intraocular lenses after 3 h. The number of glistenings gradually disappeared by 6 h for all intraocular lenses except SN60WF (12 h). Only the NS-60YG and ZCB00V intraocular lenses had no changes in weight or dimensions. Gas chromatography-mass spectrometry detected phenethyl alcohol in XY1 and SN60WF, 2-phenoxyethanol in AN6K and no compounds in the remaining intraocular lenses. A peak shift due to the carbonyl group between 1600 and 1700 cm^-1 was detected for the SN60WF and AN6K intraocular lenses only.

CONCLUSION

SN60WF had the most numerous glistenings that resolved over a longer duration. The long-term stability test confirmed elution of the intraocular lens material-derived compounds and signs of degradation for the XY1, SN60WF and AN6K intraocular lenses. NS-60YG and ZCB00V showed no signs of deterioration due to ageing. Differing manufacturing methods likely play a role in the stability of intraocular lenses.

Clinical and material degradations of intraocular lenses: A review

PURPOSE

To review the published scientific literature concerning clinical and material degradations of intraocular lenses after implantation in cataract surgery.

METHODS

A search was undertaken using the following databases: CENTRAL (including Cochrane Eyes and Vision Trials Register; The Cochrane Library: Issue 2 of 12 February 2019), Ovid MEDLINE (R) without Revisions (1996 to February week 2, 2019), Ovid MEDLINE (R) (1946 to February week 2, 2019), Ovid MEDLINE (R) Daily Update 19 February 2019, MEDLINE and MEDLINE non-indexed items, Embase (1980-2019, week 7), Embase (1974-2019, 19 February), Ovid MEDLINE (R) and Epub Ahead of Print, in-Process & Other Non-Indexed Citations and Daily (1946 to 19 February 2019), Web of Science (all years), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrial.gov) and the WHO International Clinical Trials Registry Platform (www.who.int/ictrp/search/en). Only published articles in English were selected. Search terms/keywords included 'IOL' or 'intraocular lens', combined with 'opacification', degradation, glistenings, nanoglistenings, whitening, transmittance, light scatter, discolouration/discoloration, performance, quality, material, biocompatibility, calcification, explantation and ultraviolet/UV radiation. Relevant in-article references not returned in our searches were also considered.

RESULTS

After review of the available articles, the authors included 122 publications in this review, based on the quality of their methodology and their originality. The studies included in this review were randomized controlled trials, cohort studies, case-controlled studies, case series, case reports, laboratory studies and review papers. Differing material degradations of intraocular lenses have been described and their associated pathophysiology studied. Reported anomalies include photochemical alterations, water vacuoles, internal and surface calcific deposits, surface coatings and discolouration. The nature of such changes has been shown to depend on the type of intraocular lenses material used and/or manufacturing processes and storage conditions employed. Changes in the intraocular lens can also be influenced by surgical technique, coexisting ocular pathologies and topical and systemic medications. The clinical significance of these degradations is variable, with some resulting in significant visual disturbance and the need for intraocular lens explantation and others producing only minimal visual impairments. Failure to recognize the precise nature of the problem may lead to unnecessary laser capsulotomy procedures.

CONCLUSION

Clinical degradations of intraocular lenses are uncommon but have been reported following the implantation of intraocular lenses made of differing biomaterials. Their correct identification and thorough investigation to determine the underlying cause is necessary for optimal patient management and the prevention of such problems. Choosing a lens made of a particular material may be important in patients with certain ocular conditions.

Experimental study of the mechanisms leading to the formation of glistenings in intraocular lenses by Raman spectroscopy

The phenomenon of glistenings, often appearing in intraocular lenses (IOLs) of patients after some time from the surgical operation, is potentially able to induce a poor quality of vision and, therefore, frustrate IOL implantation itself. In this paper, we combine optical microscopy with micro-Raman spectroscopy to get a deeper insight on the mechanism ruling, at microscopic scale, glistening formation. In particular, we have analyzed two types of IOLs, characterized by a different internal hydrophobicity but a similar polymer hydration coefficient. Raman imaging of single microvacuoles reveals that water creeps into the polymeric network, which traps water. Finally, applying the Principal Component Analysis (PCA) to Raman data, we provide information on the probable mechanism leading to water trapping in the two kinds of analyzed IOLs.

Effects of intraocular lens glistenings on visual function: a prospective study and presentation of a new glistenings grading methodology

Objective

To investigate the effect of intraocular lens (IOL) glistenings on visual performance and evaluate a new glistenings grading methodology.

Methods and Analysis

Thirty-four patients (34 eyes) were recruited. Corrected distance visual acuity (CDVA), mesopic gap acuity (MGA), functional contrast sensitivity (FCS) and forward light scatter were measured (Advanced Vision and Optometric Tests, City Occupational, London, UK). The IOL centre was imaged and glistenings density graded by three observers using the Miyata scale and a new system. Inter-rater reliability, association between the two grading scales, and correlations between glistenings grades and visual performance parameters were evaluated.

Results

The intraclass correlation coefficient between graders for the new grading system was 0.769 (95% Confidence Interval [CI] 0.636 to 0.868). There was a significant association between the Miyata scale and the new grading system for all graders (r_s=0.533–0.895, p≤0.001). There was no association between CDVA or MGA and glistenings grade (r_s=− 0.098, p=0.583 and r_s=0.171, p=0.359, respectively). There was no association between FCS at mesopic light levels and glistenings grade (r_s=−0.032, p=0.864), or the straylight parameter and glistenings grade (r_s=0.021, p=0.916). No association was found between the integrated straylight parameter and glistenings grade (r_s=0.078, p=0.701).

Conclusion

The new glistenings grading scale was highly reproducible. In this cohort, glistenings in the same hydrophobic acrylic IOL after cataract surgery were not associated with changes in visual function, as assessed by a series of tests not previously used in glistenings research.

Late postoperative opacification of a hydrophobic acrylic intraocular lens AcryNovaTMPC 610Y

PURPOSE

To report late postoperative opacification of a hydrophobic acrylic intraocular lens (IOL) AcryNovaTMPC 610Y as well as the clinical consequences in patients 10 years after uncomplicated cataract surgery.

MATERIALS AND METHODS

Medical records were reviewed of 23 patients (26 eyes) with AcryNovaTMPC 610Y implantated between years 2005 and 2007. Next clinical examination was performed 10 years after surgery. We assessed best corrected distance visual acuity (BCDVA), contrast sensitivity (CSV-1000E) and relative opacity of IOL material, (OCULUS Pentacam HR). Results of BCDVA and Pentacam were analysed statistically. One explanted IOL was analysed using anterior segment OCT in vitro and spectroscopic method EDX (Energy-dispersive X-ray spectroscopy).

RESULTS

Opacification led to a statistically significant reduction in the best corrected distance visual acuity (BCDVA) = (0,95 ± 0,10) versus (0,87 ± 0,20) and to increase of IOL opacity only in some lenses but statistically significant in the average (6,37 ± 2,16)% versus value of (14,22 ± 5,87)%. In the explanted IOL we have documented structural changes of primarily hydrophobic raw material leading to property of hydrophilic one.

CONCLUSION

Some batches of AcryNovaTMPC 610Y were produced from raw material of poor quality which is the cause of its structural changes and its progressive opacification.

Glistening Formation and Light Scattering in Six Hydrophobic-Acrylic Intraocular Lenses

PURPOSE

To study the glistening formation in various hydrophobic-acrylic intraocular lens (IOL) models, and to evaluate the effect of glistenings on light scattering in these IOLs.

DESIGN

Laboratory investigation.

METHODS

The susceptibility of the hydrophobic-acrylic material to develop glistenings was evaluated in 6 IOL models. Accelerated lens aging was induced by immersing the IOLs in a solution at 45 C for 24 hours and cooled to 37 C for 2.5 hours. Light microscopy and image acquisition were performed. Glistening statistics-that is, microvacuoles' (MV) number and size-were derived from image analysis. Light scattering was measured using a clinical device featuring an adaptation for in vitro IOL assessment.

RESULTS

The number of glistenings differed among the studied IOLs and ranged from 0 to 3532 MV/mm². In 1 model, glistenings were found only at the periphery, with diffuse light scattering observed centrally despite the absence of microvacuoles. The mean size of glistenings ranged from 5.2 to 10.2 μm. The mean straylight parameter of the IOLs increased from 0.6 to 5.0 deg²/sr after accelerated aging. Straylight elevation demonstrated a proportional relationship with the glistening number.

CONCLUSIONS

We showed that hydrophobic-acrylic lenses differ in their resistance to glistenings, as one group proved to be glistening-free, but the other models revealed varying grades of glistenings. Moreover, we demonstrated that the presence of glistenings results in increased straylight, and that straylight proportionally depends on the glistenings number irrespective of the IOL model. However, more research is needed to confirm that the relationship we found holds for all hydrophobic-acrylic IOLs.

Serial intraocular lens opacifications of different designs from the same manufacturer: Clinical and light microscopic results of 71 explant cases

PURPOSE

To report clinical findings and light microscopic results of 71 opacified hydrophilic acrylic intraocular lenses (IOLs).

SETTING

Vivantes Klinikum Neukoelln, Ophthalmology Department, Berlin, Germany.

DESIGN

Retrospective case series.

METHODS

Sixty-three patients (71 eyes) were referred to the clinic because of vision-impairing IOL opacification between December 2012 and September 2016 after routine cataract surgery elsewhere. The explanted IOLs were analyzed with light microscopy at the John A. Moran Eye Center (University of Utah, Salt Lake City, Utah, USA). Medical records were reviewed for visual acuity, comorbidities, and complications. Clinical follow up was 6 months.

RESULTS

Seventy-one opacified 1-piece or 3-piece hydrophilic acrylic IOLs (Lentis) of different designs from 2009 to 2012 (LS-502-1, LS-402-1Y, LS 312-1Y, LS-313-1Y, L-402, L-312) were found. Morphological findings were surface, subsurface, or deep calcifications of the IOL material. Explantation was performed 4 years ± 1.2 (SD) after initial phacoemulsification. The mean patient age was 78.6 ± 8.2 years. Ocular and systemic comorbidities were found without statistical correlation: the most frequent were diabetes, uveitis, and glaucoma. The preoperative mean corrected distance visual acuity changed from 0.63 ± 0.47 logarithm of the minimum angle of resolution (logMAR) to 0.20 ± 0.28 logMAR postoperatively (P < .001).

CONCLUSIONS

Different designs of IOLs by the same manufacturer, implanted between 2009 and 2012, developed late calcification with significant visual loss after routine cataract surgery. No medical, surgical, or ophthalmologic trigger could be determined. A manufacture issue might be the reason for the opacification.

Long-term clinical results and scanning electron microscopic analysis of the aspheric, hydrophobic, acrylic intraocular lens CT LUCIA 611P(Y)

Purpose

The aim of this study was to evaluate the clinical outcomes of a novel designed hydrophobic, acrylic, monofocal, fully preloaded intraocular lens (IOL; CT LUCIA 611P) 1 year after implantation. Scanning electron microscopic analysis regarding the optic-haptic junction and sharp edges of the IOL was performed.

Patients and methods

This is a noninterventional, observational prospective study of cataract patients who underwent implantation of the CT LUCIA 611P. Ninety-six eyes of 54 subjects were enrolled. Follow-up included visual acuity assessment, slit lamp examination with special focus on appearance of glistenings and evaluation of posterior capsule opacification (PCO). Scanning electron microscopic analysis of the new designed optic-haptic junction and edges of the IOL was performed.

Results

Best-corrected distance visual acuity increased from mean 0.48 logMAR (range 0.86-0.34) preoperatively to mean 0.02 logMAR (range 0.14 to -0.10) 1 year after surgery. Thirty-eight of 42 subjects' eyes (90.5%), which underwent bilateral surgery with implantation of the IOL, never required glasses for distance again, while 4 (9.5%) required glasses only in rare cases (eg, driving at night). The spherical equivalent was within ±0.50 D in 88 of 96 subjects (91.7%) and within ±0.75 D in 96.9% of cases. Target refraction ±1.00 D was achieved in 100% of subject eyes. No glistenings were reported in any case. From the surgeons' perspective, the wider, thicker optic-haptic transition of the IOL resulted in significantly increased stiffness, which enabled improved centering of the IOL and enhanced rotational stability and refractive predictability and stability and PCO prevention.

Conclusion

The results of this long-term observational study demonstrate the safety and efficacy of the IOL. Because of the completely new designed thicker and stiffer optic-haptic junction regarding improved characteristics of the IOL (stability in the capsular bag), some special attention has to be addressed to the slightly different behavior of the lens during implantation and unfolding process.

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.

In Vitro Analysis of AcrySof Intraocular Lens Glistening

PURPOSE

The authors studied the effects of changes in packaging solution temperature on the development of glistening in acrylic intraocular lenses (AcrySof, Alcon).

METHODS

Glistening was examined by slit lamp at each condition. In Experiment 1, AcrySof lenses were soaked in physiologic saline adjusted to 15 degrees C and 37 degrees C in an incubator. In Experiment 2, AcrySof lenses were soaked in physiologic saline adjusted to 37 degrees C and 60 degrees C for 5 min, then stored in physiologic saline adjusted to 15 degrees C. In Experiment 3, glistening formation was induced in AcrySof lenses by soaking them in warm water (37 degrees C). The lenses were allowed to dry at 15 degrees C and then soaked in physiologic saline adjusted to 15 degrees C. After storage of dry AcrySof lenses at 37 degrees C in an incubator for 10 months followed by soaking in physiologic saline adjusted to 15 degrees C, glistening formation was evaluated in Experiment 4.

RESULTS

Glistening became observable after 1 month, despite the temperature having been lowered to 15 degrees C. No glistening was observed in the lenses soaked in physiologic saline adjusted to 37 degrees C after 5 min, but glistening was observed 1 month after soaking. When allowed to dry at 15 degrees C, the glistening decreased. After 1 month of soaking at 15 degrees C, glistening was again observable.

CONCLUSIONS

AcrySof lenses soaked in warm water for a short time may change characteristics, and therefore, close monitoring of the temperature and time of soaking is necessary to prevent glistening formation.

Hydrophilic intraocular lens opacification after posterior lamellar keratoplasty - a material analysis with special reference to optical quality assessment

Background

Laboratory analysis and optical quality assessment of explanted hydrophilic intraocular lenses (IOLs) with clinically significant opacification after posterior lamellar keratoplasty (DMEK and DSAEK).

Methods

Thirteen opacified IOLs after posterior lamellar keratoplasty, 8 after descemet stripping automated endothelial keratoplasty (DSAEK), 3 after descemet membrane endothelial keratoplasty (DMEK) and 2 after both DSAEK and DMEK were analysed in our laboratory. Analyses included optical bench assessment for optical quality, light microscopy, scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDS).

Results

In all IOLs the opacification was caused by a thin layer of calciumphosphate that had accumulated underneath the anterior optical surface of the IOLs in the area spared by the pupil/anterior capsulorhexis. The calcifications lead to a significant deterioration of the modulation transfer function across all spatial frequencies of the affected IOLs.

Conclusions

The instillation of exogenous material such as air or gas into the anterior chamber increases the risk for opacification of hydrophilic IOLs irrespective of the manufacturer or the exact composition of the hydrophilic lens material. It is recommended to avoid the use of hydrophilic acrylic IOLs in patients with endothelial dystrophy that will likely require procedures involving the intracameral instillation of air or gas, such as DMEK or DS(A)EK.

Glistening Formation on a Single-Piece Prehydrated Hydrophobic Acrylic Intraocular Lens in a Diabetic Patient

PURPOSE

To report a case of intraocular lens (IOL) glistening after uneventful cataract surgery and in-the-bag implantation of an enVista MX60 IOL (Bausch & Lomb, Rochester, NY) in a patient with uncontrolled diabetes mellitus.

METHODS

Case report.

RESULTS

A 76-year-old woman with non-insulin-dependent diabetes mellitus underwent uncomplicated phacoemulsification with in-the-bag implantation of an enVista MX60 IOL. After 6 months, glistening formation within the IOL optic was observed. In the fellow pseudophakic eye, an acrylic hydrophilic Akreos Adapt AO IOL (Bausch & Lomb) was implanted without complications.

CONCLUSIONS

IOL glistening can develop with the enVista MX60 IOL, even after uneventful cataract surgeries in certain situations (eg, uncontrolled diabetes mellitus). Increased vascular permeability due to uncontrolled diabetes mellitus might have been responsible for the postoperative IOL glistening formation. [J Refract Surg. 2016;32(10):710-712.].

Effect of intraocular lens glistening size on visual quality

PURPOSE

To determine whether intraocular glistenings have an impact on light scatter and visual function.

SETTING

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

DESIGN

Retrospective cohort study.

METHODS

Pseudophakic patients with visual acuity no worse than 0.02 logMAR and no ocular pathology were enrolled. All had received a single-piece high-refractive-index acrylic intraocular lens (IOL). All IOLs were photographed, and glistenings were analyzed for size and density. Outcome measures included logMAR corrected distance visual acuity (CDVA), mesopic 10% contrast logMAR CDVA with and without glare, and straylight determination with a straylight meter (C Quant log).

RESULTS

All 79 patients had glistenings within 2 diameter groups: 6 to 25 μm and over 25 μm. Linear regression for the nonstratified group was significant for IOL glistening size versus contrast visual acuity with glare. Linear regression for the 6 to 25 μm group was significant for a measure of severity index (%area) versus the straylight meter measurements, %area/size versus straylight meter measurements, IOL age versus CDVA, IOL age versus contrast visual acuity, and IOL age versus contrast visual acuity with glare. Linear regression for the over 25 μm group was significant for IOL age versus glistening size and %area/size versus contrast visual acuity, and density versus CDVA and contrast visual acuity with glare.

CONCLUSIONS

Glistening %area, at a key size, correlated with random light scatter. The age of the IOL likely affects glistening size and visual parameters.

FINANCIAL DISCLOSURE

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

Optical and material analysis of opacified hydrophilic intraocular lenses after explantation: a laboratory study

Background

The opacification of hydrophilic intraocular lenses (IOLs) is a very rare complication in terms of absolute numbers. We report on the analyses of opacified Euromaxx ALI313Y and ALI313 IOLs (Argonoptics, Germany) using light and scanning electron microscopy, X-ray spectroscopy and optical bench analysis.

Methods

Opacified Euromaxx ALI313Y and ALI313 IOLs were explanted after patients presented with a decrease in visual acuity. The explants were sent to our laboratory and examined using light and scanning electron microscopy. The composition of the deposits was analysed using X-ray spectroscopy. The optical quality of the intraocular lens (IOL) was assessed using the OptiSpheric IOL PRO optical bench (Trioptics GmbH Wedel, Germany). Modulation transfer function (MTF) was measured at all spatial frequencies and United States Air Force (USAF) 1951 resolution target pictures were documented.

Results

Macroscopically, the entire optic was opacified in all IOLs. Light and scanning electron microscopy revealed numerous fine, granular, crystalline-like deposits, which were always distributed in a line parallel to the anterior and posterior surfaces of the IOLs. X-ray spectroscopy could prove the deposits consisted of Calcium and Phosphate. Measurements in the optical bench showed deterioration of MTF values at all spatial frequencies and the USAF target pictures demonstrated a significant reduction of brightness as well as resolution with the opacified IOLs.

Conclusions

The calcification of hydrophilic IOLs only occurs rarely. The exact chemical composition of the deposits can be assessed by means of X-ray spectroscopy. Optical quality analysis of the explanted Euromaxx ALI313Y and ALI313 IOLs showed significant reduction of MTF values, which was confirmed by USAF target pictures.

A pilot study to determine if intraocular lens choice at the time of cataract surgery has an impact on patient-reported driving habits

PURPOSE

To determine if intraocular lens (IOL) choice at the time of cataract surgery affects driving habits.

MATERIALS AND METHODS

Pseudophakes who were 28-35 months postbilateral cataract surgery with one of two contemporary one-piece hydrophobic acrylic IOLs (SN60WF or ZCB00) were asked to complete the Driving Habits Questionnaire, a validated instrument for determining self-reported driving status, frequency, and difficulty. To determine if there were any differences in driving habits between the two groups, t-tests and χ (2) tests were used.

RESULTS

Of 90 respondents, 72 (40 SN60WF and 32 ZCB00) were still active drivers. The SN60WF-implanted subjects were less likely to drive at the same speed or faster than the general flow of traffic, less likely to rate their quality of driving as average/above average, less likely to have traveled beyond their immediate neighborhood, less likely to drive at night, more likely to have moderate-to-severe difficulty driving at night, and more likely to have self-reported road traffic accidents. The differences did not reach statistical significance.

CONCLUSION

Changes in patients' driving habits 2-3 years after cataract surgery may be associated with the type of IOL implanted. A larger study, powered to demonstrate statistical significance, is needed to verify the trends identified in this pilot study and discover possible contributing factors.

Glistenings 9 years after phacoemulsification in hydrophobic and hydrophilic acrylic intraocular lenses

PURPOSE

To compare the development of glistenings after implantation of a hydrophobic acrylic intraocular lens (IOL) (AcrySof SA60AT) and a hydrophilic IOL (BL27) and evaluate the effect on corrected distance visual acuity (CDVA) and contrast sensitivity 9 years postoperatively.

SETTING

St. Erik Eye Hospital, Stockholm, Sweden.

DESIGN

Prospective randomized clinical trial.

METHODS

One of 3 experienced cataract surgeons performed standard phacoemulsification in 1 eye of each patient. The patients were randomized to implantation of a hydrophobic acrylic IOL or a hydrophilic acrylic IOL. Both IOLs had sharp posterior edges. The CDVA and contrast sensitivity were measured 9 years postoperatively. Scheimpflug images of the IOLs were obtained to analyze glistenings, which were graded subjectively at the slitlamp and quantified objectively with digital image analysis using computer software.

RESULTS

Seventy-eight of the 120 patients were available for the 9-year follow-up examination. Patients with the hydrophilic IOL had statistically significantly fewer glistenings (P < .001). The development of glistenings was not correlated with IOL power, CDVA, or contrast sensitivity.

CONCLUSIONS

After 9 years, the hydrophobic IOL developed more glistenings than the hydrophilic IOL. Glistenings did not affect CDVA or contrast sensitivity.

FINANCIAL DISCLOSURE

Neither author has a financial or proprietary interest in any material or method mentioned.

Glistening in glaucomatous eyes: visual performances and risk factors

PURPOSE

To analyse risk factors and visual performances of glaucomatous eyes with glistening in the intra-ocular lens (IOL).

METHODS

Prospective study performed between November 2010 and April 2011 and involving 67 consecutive glaucomatous eyes (47 patients), who previously had a phacoemulsification with a hydrophobic acrylic IOL implanted in the capsular bag. Glistening was classified in three groups of severity grade: G0 (<50 microvacuoles per mm(2) ), G1 (50-150 microvacuoles per mm(2) ), and G2 (>150 microvacuoles per mm(2) ). All eyes underwent a best-corrected visual acuity evaluation (BCVA, LogMAR scale), a complete clinical examination, a visual field test, a contrast sensitivity evaluation and a wavefront analysis of high-order aberrations (HOAs) using a Shack-Hartmann aberrometer. Eyes with a posterior capsular opacification and a BCVA>0.30 LogMAR were excluded.

RESULTS

Twenty six eyes (38.8%) had a grade 0, 12 eyes (17.9%) a grade 1 and 29 eyes (43.3%) a grade 2 of glistening severity grade. The mean follow-up after cataract surgery was 35.2 ± 24.2 months and was significantly higher for G1 and G2 groups (p < 0.001). A higher number of topical glaucoma medication were associated with a higher glistening severity grade (p < 0.05). G1 and G2 groups had significantly lower mean contrast sensitivity values at high spatial frequencies and significantly higher loss variance (LV) values of the visual field test (p < 0.05). There was no significant difference in mean BCVA between groups (p = 0.455).

CONCLUSIONS

In glaucomatous eyes, glistening increased with time was associated with the number of topical glaucoma medications daily instilled and altered visual performances. It should be a consideration for glaucoma patients who are more likely to develop glistening within the IOL optic.

Evaluation of the impact of light scatter from glistenings in pseudophakic eyes

PURPOSE

To study the impact of light scatter from glistenings in pseudophakic eyes using ray tracing in a model eye

SETTING

Department of Research, Advanced Vision Science, Inc., Goleta, California, USA.

DESIGN

Mathematical modeling and simulation.

METHODS

A pseudophakic eye model was constructed in Zemax using the Arizona eye model as the basis. The Mie scattering theory was used to describe the intensity and direction of light as it scatters for a spherical particle immersed in a given media (intraocular lens [IOL]). The modeling and evaluation of scatter and modulation transfer function (MTF) were performed for several biomaterials with various size and density of glistenings under scotopic, mesopic, and photopic conditions.

RESULTS

As predicted by the Mie theory, the amount of scatter was a function of the relative difference in refractive index between the media and the scatterer, the size of the scatterer, and the volume fraction of the scatterer. The simulation demonstrated that an increase in density of glistenings can lead to a significant drop in the MTF of the IOL and the pseudophakic eye. This effect was more pronounced in IOLs with smaller cavitations, and the observation was consistent for all tested biomaterials.

CONCLUSIONS

Mathematical modeling demonstrated that glistenings in IOLs will lead to reduction in the MTF of the IOL and the pseudophakic eye. The loss in MTF was more pronounced at high densities and small cavitation sizes across all biomaterials. Inconsistent and poor clinical quantification of glistenings in IOLs may explain some inconsistencies in the literature.

Analysis of glistenings in hydrophobic acrylic intraocular lenses on visual performance

AIM

To assess patients' visual performance with glistenings in one piece soft hydrophobic acrylic intraocular lenses (IOLs) (Alcon) 2 years postoperatively.

METHODS

This cross section trial included 120 eyes with one piece IOL at 2 years postoperatively. Glistening was classified in 4 groups, ranging from 0 (none) to 3 (most evident) according to their severity in IOLs optics observed under a slit lamp. All eyes underwent a uncorrected and best-corrected visual acuity evaluation (UCVA and BCVA, LogMAR scale), a complete clinical examination, a contrast sensitivity (CS) evaluation by F.A.C.T chart, and a visual field test by Humphrey Field Analyzer ‖ (HFA). One-way ANOVA was used for quantitative data, while Pearson χ (2) test was used for qualitative data to analyze the visual function of 4 glistening groups.

RESULTS

Totally 120 eyes were enrolled with 30 eyes in each glistening group. There was no statistical correlation between glistening grades and patients' age, IOLs power, postoperative UCVA and BCVA (P>0.05). Quantificationally, CS values among each group were not statistically different. However, qualitative analysis showed there were more eyes in grade 3 group than in grade 0 group having abnormally declined CS at high spatial frequency (10% vs 36.7% at 18 cpd, P=0.029; 6.7% vs 26.7% at 12 cpd, P=0.013). Mean deviation (MD) of the visual field test was -2.14±2.31, -1.97±2.23, -3.02±3.17, -4.12±3.38 in group 0 to 3 respectively. There was a significant decrease in the most serious glistenings group (P =0.018).

CONCLUSION

Glistenings may potentially have an impact on contrast sensitivity at high spatial frequency and MD in visual field test.

Comparison of the Retinal Straylight in Pseudophakic Eyes with PMMA, Hydrophobic Acrylic, and Hydrophilic Acrylic Spherical Intraocular Lens

Purpose. To investigate the intraocular straylight value after cataract surgery. Methods. In this study, 76 eyes from 62 patients were subdivided into three groups. A hydrophobic acrylic, a hydrophilic acrylic, and a PMMA IOL were respectively, implanted in 24 eyes, 28 eyes, and 24 eyes. Straylight was measured using C-Quant at 1 week and 1 month postoperatively in natural and dilated pupils. Results. The hydrophilic acrylic IOLs showed significantly lower straylight values than those of the hydrophobic acrylic IOLs in dilated pupils at 1 week and 1 month after surgery (P < 0.05). However, the straylight values of the hydrophilic acrylic IOLs were the lowest among the three IOL groups. No significant difference was observed in straylight between 1 week and 1 month postoperatively in each group with natural and dilated pupils (P > 0.05). Moreover, no significant difference was found in straylight between natural and dilated pupils in each group at 1 week and 1 month postoperatively (P > 0.05). Conclusions. Although the hydrophobic acrylic IOL induced more intraocular straylight, straylight differences among the 3 IOLs were minimal. Pupil size showed no effect on intraocular straylight; the intraocular straylight was stable 1 week after surgery.

Safety and effectiveness of a single-piece hydrophobic acrylic intraocular lens (enVista®) - results of a European and Asian-Pacific study

Purpose

To evaluate the safety and effectiveness of a single-piece hydrophobic acrylic intraocular lens (IOL) (enVista® MX60; Bausch and Lomb Incorporated, Rochester, NY, USA) following implantation to correct aphakia subsequent to extracapsular cataract extraction in adults.

Subjects and methods

This was an open-label, non-interventional, observational study conducted in 19 university and private-practice settings in Europe and the Asia-Pacific region to investigate clinical outcomes of the MX60 IOL in standard practice. Eligible subjects were at least 18 years of age and had undergone standard phacoemulsification and extracapsular cataract extraction with implantation of the MX60 IOL. The primary safety endpoint was the occurrence of adverse events, and the primary effectiveness endpoints included visual and refractive outcomes and stability, with data collected up to 2 years post-procedure.

Results

In this multicenter study, pooled data of 255 eyes were collected and analyzed. Excellent visual and refractive outcomes and stability were demonstrated. At postoperative visit 4 (61–180 days postoperative), 62.2% of subjects achieved a Snellen best-corrected distance visual acuity (CDVA) of 20/20 (decimal 1.00), and 97.8% of subjects achieved a CDVA of 20/40 (decimal 0.50) or better. One eye (1.0%) underwent neodymium:yttrium aluminum garnet capsulotomy at 12 months post-procedure. No glistenings of any grade were reported for any subject at any visit. Adverse events were infrequent and were consistent with incidences generally reported with cataract surgery.

Conclusion

This study, which enrolled all comers, provided evidence of the excellent safety and effectiveness of the MX60 IOL in standard practice. Favorable clinical outcomes included outstanding visual and refractive outcomes and stability. No glistenings were reported at any postoperative visit.