Calcification of modern foldable hydrogel intraocular lens designs

Intraocular lens calcification in a patient with Ehlers-Danlos syndrome

Introduction

Calcification of hydrophilic intraocular lenses (IOL) is a rare complication following cataract surgery. Secondary calcification is described as due to host factors or changes in the IOL environment and uveitis, proliferative diabetic retinopathy and sequelae of ocular surgery are recognised potentiators. The impact of systemic connective tissue disease on IOL opacification is yet to described.

Purpose

To describe the clinical presentation and management of a young patient, with a rare subtype of Ehlers-Danlos syndrome, who presented with secondary IOL calcification 14 years after primary IOL insertion.

Observations

Floret-like lesions were observed on the IOL surface. Positive staining for calcification was observed with Alizarin red and von Kossa method on laboratory analysis.

Conclusions and importance

Patients with systemic connective tissue disease, such as a subtype of Ehlers-Danlos, may present with secondary IOL calcification many years after primary lens insertion. This poses an additional consideration when implanting IOLs in these patients.Good visual acuity can be achieved with IOL exchange.

Material Analysis of Explanted Calcified Silicone Intraocular Lenses in Association with Asteroid Hyalosis

INTRODUCTION

The aim of this study was to analyze posterior surface opacification in explanted silicone intraocular lenses (IOLs) with clinicopathologic correlation to asteroid hyalosis.

METHODS

In a laboratory setup, 12 explanted silicone IOLs underwent laboratory analyses, including light microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy for elemental composition (EDX). Relevant clinical data were obtained for each case, including gender, age at IOL implantation, dates of implantation and explantation, as well as history of neodymium-dopped yttrium aluminum garnet (Nd:YAG) laser treatments or other opacification removal attempts. High-resolution optical coherence tomography (OCT) images were obtained in vitro with an anterior segment OCT device (Anterion, Heidelberg Engineering, Heidelberg, Germany).

RESULTS

Calcification located at the posterior optic surface of each lens was identified through SEM and EDX analyses, revealing deposits composed of hydroxyapatite. In all cases, IOL polishing using Nd:YAG laser had been attempted prior to IOL exchange. The clinical functional data showed that this type of IOL opacity led to increase in straylight and subjective symptoms of glare.

CONCLUSIONS

Silicone IOLs can develop posterior surface calcification in eyes with asteroid hyalosis. There are mechanical techniques of cleaning the IOL surface but in many cases, IOL explantation is the only sustainable way to reduce the patients' straylight levels and glare symptoms. Due to the risk of posterior surface calcification, silicone IOL implantation should be avoided in eyes with asteroid hyalosis.

A unique late-onset intraocular lens opacification 23 years after implantation: a clinical and laboratory case report

We report an unusual, rare case of opacification of the hydrophilic acrylic intraocular lens (IOL) 23 years after the initial surgery with significant visual deterioration. Opacification of the hydrophilic acrylic IOL was primarily due to the formation of folds on the surface of the lens material, and less so due to calcium phosphate deposits. Calcification opacification can be attributed to recent events, as evidenced by deposits of dicalcium phosphate dihydrate (CaHPO42H2O) and octacalcium phosphate (Ca8H2(PO4)65H2O), both of which are transient calcium phosphate phases, converting hydrolytically to the thermodynamically most stable hydroxyapatite (Ca10(PO4)6(OH)2). To our knowledge, this case of hydrophilic acrylic IOL opacification is the only one that has been described so late, 23 years after cataract surgery.

Qualitative and quantitative analysis of an explanted opacified hydrophilic IOL after over two years from cataract surgery

Opacification of hydrophilic intraocular lenses (IOLs) is an uncommon complication, that can appear after uneventful cataract surgery. We report a case of opacified Hydroview® IOL in a 76-year-old woman, with a previous history of pars plana vitrectomy with silicon oil tamponade in her right eye for a proliferative diabetic retinopathy, who developed an opacification of the IOL after over two years from a silicon oil/BSS exchange in combination with an uneventful phacoemulsification. The patient complained about a progressive decrease in her visual acuity. The slit-lamp examination confirmed the opacification of the IOL. Therefore, because of blurred vision, a combined procedure of explant and exchange of the IOL was performed in the same eye. Qualitative (Optic microscope, X-Ray powder Diffraction (XRD), Scanning Electron Microscopy (SEM)) and quantitative (Instrumental Neutron Activation Analysis (INAA)) analysis of the IOL material were performed. Here, our aim is to report the acquired data of the explanted Hydroview® H60M IOL.

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.

Explantation of a sutureless scleral fixated Carlevale intraocular lens due to calcification: a clinical and laboratory report

BACKGROUND

Hydrophilic intraocular lens opacification is a rare complication due to calcification. With current new surgical techniques, including lamellar endothelial keratoplasty and vitrectomies, this irreversible complication is becoming more common. In this case study, we present clinical and laboratory features of a case of Carlevale hydrophilic acrylic IOL calcification.

CASE PRESENTATION

Observational case report of a single incident case. An 83-year-old man was referred to our ophthalmic department complaining of right eye vision blurring for six months. Slit-lamp biomicroscopy revealed IOL opacification. Deposits of calcium phosphate were found both on the IOL's surface and inside it, according to thorough investigation using optical, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) spectrometry.

CONCLUSIONS

To the best of our knowledge, this is the first case to describe the laboratory evidence of Carlevale hydrophilic IOL calcification, suggesting possible explanation mechanisms based on underlying pathology and surgical technique. It reminds us that these findings suggest that physicians should be aware of possible hydrophilic IOL calcification.

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.

Clinical Characteristics of Patients with Intraocular Lens Calcification after Pars Plana Vitrectomy

AIM

To determine the clinical risk factors that may increase the occurrence of intraocular lens (IOL) calcification in patients who had undergone pars plana vitrectomy (PPV).

METHODS

The medical records of 14 patients who underwent IOL explantation due to clinically significant IOL opacification after PPV were reviewed. The date of primary cataract surgery, technique and implanted IOL characteristics; the time, cause and technique of PPV; tamponade used; additional surgeries; the time of IOL calcification and explantation; and IOL explantation technique were investigated.

RESULTS

PPV had been performed as a combined procedure with cataract surgery in eight eyes and solely in six pseudophakic eyes. The IOL material was hydrophilic in six eyes, hydrophilic with a hydrophobic surface in seven eyes and undetermined in one eye. The endotamponades used during primary PPV were C2F6 in eight eyes, C3F8 in one eye, air in two eyes and silicone oil in three eyes. Two of three eyes underwent subsequent silicone oil removal and gas tamponade exchange. Gas in the anterior chamber was detected in six eyes after PPV or silicone oil removal. The mean interval between PPV and IOL opacification was 20.5 ± 18.6 months. The mean BCVA in logMAR was 0.43 ± 0.42 after PPV, which significantly decreased to 0.67 ± 0.68 before IOL explantation for IOL opacification (p = 0.007) and increased to 0.48 ± 0.59 after the IOL exchange (p = 0.015).

CONCLUSIONS

PPV with endotamponades in pseudophakic eyes, particularly gas, seems to increase the risk for secondary IOL calcification, especially in hydrophilic IOLs. IOL exchange seems to solve this problem when clinically significant vision loss occurs.

Imaging Function and Relative Light Transmission of Explanted Opacified Hydrophilic Acrylic Intraocular Lenses

We evaluated the influence of intraocular lens (IOL) opacification on the optical performance of explanted hydrophilic acrylic IOLs. We performed a laboratory analysis of 32 Lentis LS-502-1 (Oculentis GmbH, Berlin, Germany) IOLs, explanted due to opacification, in comparison with six clear unused samples of the same IOL model. Using an optical bench setup, we obtained modulation transfer function (MTF), Strehl ratio, two-dimensional MTF, and United States Air Force (USAF) chart images. In addition, we assessed light transmission through the IOLs. The MTF values of opacified IOLs at 3-mm aperture were similar to those of clear lenses, with the median (interquartile range) values of 0.74 (0.01) vs. 0.76 (0.03) at the spatial frequency of 50 line pairs per millimeter in clear and opacified IOLs, respectively. The Strehl ratio of opacified lenses was not lower than that of clear lenses. The USAF-chart analysis showed a considerable reduction in brightness in opacified IOLs. The median (interquartile range) relative light transmission of opacified IOLs in comparison to clear lenses was 55.6% (20.8%) at the aperture size of 3 mm. In conclusion, the explanted opacified IOLs had comparable MTF values to those of clear lenses but significantly reduced light transmission.

UV-VIS Curable PEG Hydrogels for Biomedical Applications with Multifunctionality

Multifunctional biomedical materials capable of integrating optical functions are highly desirable for many applications, such as advanced intra-ocular lens (IOL) implants. Therefore, poly(ethylene glycol)-diacrylate (PEG-DA) hydrogels are used with different photoinitiators (PI). In addition to standard UV PI Irgacure, Erythrosin B and Eosin Y are used as PI with high sensitivity in the optical range of the spectrum. The minimum PI concentrations for producing new hydrogels with PEG-DA and different PIs were determined. Hydrogel films were obtained, which were applicable for light-based patterning and, hence, the functionalization of surface and volume. Cytotoxicity tests confirm cytocompatibility of hydrogels and compositions. Exploiting the correlation of structure and function allows biomedical materials with multifunctionality.

Opacification of refractive bifocal intraocular lens in one month: Three case reports

RATIONALE

Multifocal intraocular lenses (IOLs) are used widely. However, the discovery of LS-313 MF15/30 (Oculentis B.V.) opacity during surgery has not yet been reported. This article reports 3 cases of LS-313 MF15/30 (Oculentis B.V.) IOL opacity found during cataract surgery implantation within 1 month.

PATIENT CONCERNS

Three patients underwent cataract surgery, and opacification of their IOL (LS-313 MF15/30, Oculentis B.V.) was found intraoperatively.

DIAGNOSIS

The patient was diagnosed with a postoperative intraocular opacity.

INTERVENTIONS

In case 1, the surgeon scrubbed the IOL with intraocular perfusion fluid and a gelatin sponge swab to reduce opacity in the central optical area of the IOL and then implanted it into the capsule bag. In case 2, the surgeon used the infusion-aspiration polishing mode for cleaning. To avoid IOL wear and bag damage, washing was stopped when turbidity in the center of the optical area was reduced. In case 3, we learned from our previous experience that the surgeon cut the IOL into 2 pieces and moved it out at the main incision, which was replaced and implanted with a brand new IOL, after the implanted IOL was again found cloudy.

OUTCOMES

In case 1, more than 10 months after the surgery, the IOL was restored to transparency, no obvious eye discomfort was noted, and uncorrected visual acuity was 20/25. In case 2, the patient's IOL surrounding area was still partially turbid after more than 10 months of follow-up. In case 3, the patient's uncorrected visual acuity on postoperative day 1 was 20/20, and the best-corrected visual acuity was 20/20.

LESSON

There are many reasons for the opacification of the IOL. In addition to the patient's own factors, the material, production, and packaging of the IOL, as well as the influence of external environmental temperature, the influence of the IOL implant instrument should not be ignored and needs to be considered.

Intraoperative and Postoperative Intraocular Lens Opacifications: Analysis of 42545 Cases

Purpose

To assess the types and causes of intraocular lens (IOL) turbidity in a tertiary eye center. Setting. Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China.

Design

Retrospective case series.

Methods

Patients who underwent uncomplicated phacoemulsification and IOL implantation for cataract between January 2015 and December 2019 were included. Medical records were reviewed of participants with intraoperative or postoperative IOL opacification for clinical data, artificial crystal materials, and causes of the opacification.

Results

A total of 42545 IOLs were implanted in the five years, comprising 25471 (66.0%) hydrophilic IOLs, 11881 (27.9%) hydrophobic IOLs, and 2601 (6.1%) hydrophilic-hydrophobic acrylic IOLs. Among the operated eyes, 14 eyes (13 patients) experienced IOL opacification, which was permanent for 10 IOLs, including 7 (0.6%) hydrophilic IOLs (860UV) and 3 (0.2%) hydrophilic-hydrophobic acrylic IOLs (L-312). The mean interval between surgery and diagnosis of permanent opacification was 34.4 ± 18.4 (SD) months (range, 12 to 59 months). Permanent IOL clouding led to a statistically significant reduction in best corrected visual acuity (mean, 0.64 ± 0.4 logMAR; P < 0.004). Acute IOL clouding occurred in four eyes during the implantation of a hydrophilic-hydrophobic acrylic IOL of L-312, 809M, or 839M and returned to transparency several hours later. All four procedures were performed in winter, with the mean outside temperature being −5.75°C.

Conclusions

The rate of IOL opacification was 0.03%. Both delayed postoperative and acute intraoperative opacifications occurred with various characteristics in IOLs made of different materials and designs. Clinicians should be aware of this risk for cataract surgery.

The Multi-Elemental Composition of the Aqueous Humor of Patients Undergoing Cataract Surgery, Suffering from Coexisting Diabetes, Hypertension, or Diabetic Retinopathy

The aim of the study was the multi-elemental analysis of aqueous humor (AH) collected from patients undergoing cataract surgery. The study included: 16 patients with age-related macular degeneration AMD (99 controls), 10 patients with retinopathy (105 controls), 61 patients with hypertension (54 controls), and 33 patients with coexisting diabetes (82 controls). The control groups were recruited from patients with a lack of co-existing disease characterizing the specified studied group. The measurements were performed by the use of inductively coupled plasma optical emission spectrometry (ICP-OES). The statistical analysis was carried out using non-parametric testing (Mann–Whitney U). The level of significance was set at p = 0.05. The data obtained revealed substantial variations in elemental composition between the test groups in comparison to the controls. However, the significant variations concerned only a few elements. The phosphorous (P) level and the ratio of P/Ca were significant in retinopathy and diabetes, whereas cobalt (0.091 ± 0.107 mg/L vs. 0.031 ± 0.075 mg/L; p = 0.004) was significant in AMD. In co-existing hypertension, the levels of tin (0.293 ± 0.409 mg/L vs. 0.152 ± 0.3 mg/L; p = 0.031), titanium (0.096 ± 0.059 mg/L vs. 0.152 ± 0.192 mg/L; p = 0.045), and ruthenium (0.035 ± 0.109 mg/L vs. 0.002 ± 0.007 mg/L; p = 0.006) varied in comparison to the controls. The study revealed inter-elemental interactions. The correlation matrices demonstrated the domination of the positive correlations, whereas negative correlations mainly concerned sodium.

Laboratory evaluation of higher-order aberrations and light scattering in explanted opacified intraocular lenses

Background

Intraocular lens (IOL) calcification is a serious condition that can only be treated by removing the clouded lens. Since explantation bears the risk of complications, it is often deferred until the patient finds the symptoms intolerable. Usually, as the IOL opacifies, visual acuity is minimally affected early on. In this study, we assessed the impact of IOL opacification on optical quality.

Methods

We analyzed ten opacified explanted IOLs (Oculentis GmbH). Wavefront aberrations were obtained with a SHSOphthalmic device (Optocraft GmbH), which features a Hartmann-Shack sensor. The root mean square (RMS) of higher-order aberrations (HOAs) was compared. The effect of calcification on image quality was assessed through the Strehl ratio (SR). We detected light scattering with a C-Quant (Oculus GmbH) and expressed it as a straylight parameter.

Results

At 2 mm, 3 mm and 4 mm, the mean RMS (±standard deviation) was 0.033 μm (±0.026 μm), 0.044 μm (±0.027), and 0.087 μm (±0.049), respectively. The mean SR value was 0.81 ± 0.15 at 3 mm, with four IOLs showing a nearly diffraction-limited performance, but in two explants, opacification precluded reliable measurements. Increased straylight was found in all opacified IOLs with a mean value of 150.2 ± 56.3 deg²/sr at 3 mm.

Conclusions

We demonstrated that IOL opacification induces HOAs. However, the RMS remained low, which resulted only in a slight reduction of the SR-derived optical quality. On the other hand, we found a severe straylight elevation in the opacified lenses, which may result in dysphotopsia, such as glare, and subjective complaints, despite good visual acuity.

[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.

Delayed surface opacification of a hydroview intraocular lens

The insertion of an intraocular lens during cataract surgery is routine but delayed opacification of hydrophilic foldable intraocular lenses (IOLs) has been increasingly noticed as a late post-operative complication. Such opacification may present with reduced visual acuity and can be diagnosed with slitlamp biomicroscopy. Lens explantation may be required. We report an 89-year-old female presenting with opacification of a Hydroview IOL and correlate the clinical findings of the lens in situ with the light microscopy of the explanted lens, as well as transmission electron microscopy (TEM), scanning electron microscopy (SEM) and elemental analysis. Pathological analysis of an explanted IOL may assist in a better understanding of the condition and may become relevant in medico-legal proceedings.

Incidence and Risk of Scleral-Fixated Akreos (AO60) Lens Opacification: A Case Series

Purpose:

Postoperative hydrophilic intraocular lens opacification can lead to decreased vision and may require intraocular lens exchange. This study aims to identify the incidence of scleral-fixated Akreos AO60’s (Bausch + Lomb) lens opacification and risk factors for this phenomenon.

Methods:

This is a retrospective case series of all patients who underwent scleral-fixated Akreos AO60 lens at our institution between January 1, 2015 and December 31, 2019. The following data were recorded: age, sex, medical history, indication for Akreos AO60 implantation, laterality, ocular history, previous ocular surgical procedures, subsequent intraocular surgical procedures after the Akreos implantation, lens opacification, visual significance of opacification, and Akreos explantation. Intraoperative and postoperative complications were recorded. Main outcome measures were the overall incidence of Akreos lens opacification as well as the incidence of these eyes undergoing subsequent intraocular surgery.

Results:

A total of 262 eyes of 257 patients underwent Akreos lens implantation. Overall, 2% (5 of 262) developed lens opacification. Two patients had Descemet stripping automated endothelial keratoplasty (DSAEK) concurrently with Akreos implantation. One patient underwent subsequent Baerveldt glaucoma implantation and DSAEK. The fourth patient had vitrectomy with sulfur hexafluoride gas followed by DSAEK. This represents a 25% (4 of 16) opacification rate among all patients who underwent DSAEK ( P ≤ .01, Fisher exact test). One patient developed opacification after undergoing 2 vitrectomies for retinal detachment in the absence of DSAEK.

Conclusions:

Akreos lens opacification can be visually significant and may occur after a retinal or corneal procedure that involves the use of intraocular gas or air.

A rare intraocular lens surface foreign body during phacoemulsification surgery: A case report

RATIONALE

Only a few cases of intraocular lens (IOL) opacification during phacoemulsification surgery have been reported in the literature; intraoperative emergency due to IOL surface foreign body is even rarer.

PATIENT CONCERNS

A 76-year-old woman underwent uncomplicated cataract surgery in her right eye. A triangular transparent seemingly foreign body tightly attached to the posterior surface of the IOL was found during IOL implantation; the IOL surface foreign body prevented the patient from obtaining satisfactory visual acuity after surgery.

DIAGNOSIS

IOL surface foreign body.

INTERVENTIONS

After confirmation of the surface foreign body by swept-source optical coherence tomography (IOL Master 700), the surface foreign body was removed in a second surgery. After surgery, the IOL was still well centered.

OUTCOMES

Fortunately, the patient achieved distinctly improved vision without any visual disturbances in her right eye. To identify the material of the foreign body, it was examined by Fourier-transform infrared spectroscopy (FTIR).

LESSONS

This case suggests that surgeons should carefully observe IOLs before implantation. In addition, effective preoperative planning and skillful surgery can remove foreign bodies smoothly and improve patient vision.

Polymeric Materials for Eye Surface and Intraocular Applications

Ocular applications of polymeric materials have been widely investigated for medical diagnostics, treatment, and vision improvement. The human eye is a vital organ that connects us to the outside world so when the eye is injured, infected, or impaired, it needs immediate medical treatment to maintain clear vision and quality of life. Moreover, several essential parts of the eye lose their functions upon aging, causing diminished vision. Modern polymer science and polymeric materials offer various alternatives, such as corneal and scleral implants, artificial ocular lenses, and vitreous substitutes, to replace the damaged parts of the eye. In addition to the use of polymers for medical treatment, polymeric contact lenses can provide not only vision correction, but they can also be used as wearable electronics. In this Review, we highlight the evolution of polymeric materials for specific ocular applications such as intraocular lenses and current state-of-the-art polymeric systems with unique properties for contact lens, corneal, scleral, and vitreous body applications. We organize this Review paper by following the path of light as it travels through the eye. Starting from the outside of the eye (contact lenses), we move onto the eye's surface (cornea and sclera) and conclude with intraocular applications (intraocular lens and vitreous body) of mostly synthetic polymers and several biopolymers. Initially, we briefly describe the anatomy and physiology of the eye as a reminder of the eye parts and their functions. The rest of the Review provides an overview of recent advancements in next-generation contact lenses and contact lens sensors, corneal and scleral implants, solid and injectable intraocular lenses, and artificial vitreous body. Current limitations for future improvements are also briefly discussed.

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.

Subsurface calcification of hydrophilic refractive multifocal intraocular lenses with a hydrophobic surface: A case series

RATIONALE

Opacification of monofocal intraocular lenses (IOLs) of various designs and materials has been reported. Hydrophilic acrylic IOLs are more prone to opacification than hydrophobic IOLs, but IOL surface modification by hydrophobic materials may improve biocompatibility, and few opacifications of such monofocal lenses have been reported to date. However, here we describe the characteristics of opacification of hydrophilic refractive multifocal IOLs with a hydrophobic surface modification in a cluster of patients who underwent uneventful cataract surgery.

PATIENT CONCERNS

In this retrospective observational case series, the medical records of 7 patients in whom opacification of the IOL was identified after implantation of LS-313 MF30 (Lentis M plus, Oculentis), from November 2017 to May 2019, were reviewed.

DIAGNOSIS

All patients had undergone bilateral implantation of LS-313 MF30 IOLs. Ten eyes of 7 patients showed significant opacification at a mean 49.1 ± 10.2 months postoperatively.

INTERVENTIONS

The IOLs of 4 cases were explanted.

OUTCOMES

All of the opacified cases had received LS-313 MF30 IOLs from February 2014 to August 2014 and experienced decreased visual acuity after 44.6 ± 10.5 months. The explanted IOLs of 4 cases were evaluated by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Alizarin-red, and von Kossa staining. These explanted IOLs showed fine and evenly distributed, whitish deposits on the entire IOL, particularly below the surface. Although the constituent of the deposits was identified as calcium by Alizarin-red and von Kossa stain, SEM, and EDX analysis showed no surface deposits of calcium. Paraffin-embedded sections of the IOLs were prepared, and calcium deposition was confirmed by EDX analysis at the subsurface region of the IOL.

LESSENS

Significant opacification of these hydrophilic refractive multifocal IOLs with hydrophobic surface modification was found to be due to abnormal calcification of the subsurface of the IOL. Clinicians must be aware of the opacification of this IOL design, despite surface modification. In particular, it should be noted that there is a high likelihood that the patient may experience vision-related symptoms even with moderate opacity and that opacification may lead to a burdensome IOL exchange.

Large-scale opacification of a hydrophilic/hydrophobic intraocular lens

PURPOSE

To determine the prevalence and risk factors related to the opacification of the LS-502-1 intraocular lens.

METHODS

Cross-sectional study including patients submitted to cataract surgery between January 2010 and March 2012, with implantation of the LS-502-1 intraocular lens. Past medical history was registered and a complete ophthalmologic evaluation, that included best-corrected visual acuity, slit-lamp examination and fundoscopy, was performed. Anterior segment photographs were taken whenever intraocular lens opacification was present.

RESULTS

One hundred and sixty-nine eyes of 154 patients were included, mean age 78.5 ± 7.9 years. The average follow-up after intraocular lens implantation was 65.6 ± 10.0 months. Intraocular lens opacification was seen in 53.3% (n = 90) and presented as one of four different patterns: peripheral (15.6%, n = 14), central (4.4%, n = 4), diffuse (71.1%, n = 64) and superficial white deposits (8.9%, n = 8). There was no statistically significant association with systemic or ophthalmic conditions. In patients with bilateral implantation, intraocular lens opacification in one eye was significantly related to intraocular lens opacification in the fellow eye. A significant variability in opacification was found across intraocular lens serial numbers: the odds ratio for opacification in intraocular lens with serial number beginning with 200003 was 6.0 when comparing with the remaining lenses.

CONCLUSION

The opacification prevalence of the LS-502-1 intraocular lens was 53.3%, which is the highest ever described for any intraocular lens model. Our results suggest that this occurrence is secondary to an interaction between unknown patient variables and problems related to intraocular lens manufacturing and storage procedures.

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.

Refractive Nightmares Revisited: Calcification of a Multifocal Intraocular Lens

BACKGROUND/AIM

Cataract is the leading cause of reversible blindness and visual impairment worldwide. Although cataract surgery using phacoemulsification and intraocular lens (IOL) implantation is one of the commonest surgical procedures, IOL opacification remains a potential complication that can affect the visual outcome of the operation.

CASE REPORT

A 50-year-old female patient presented to our clinic complaining of glare and blurry vision in her right eye over the previous 6 weeks. She had undergone bilateral refractive lens exchange elsewhere 9 months earlier. Her unaided distance visual acuity was 8/10 in the right eye and 10/10 in the left. On slit-lamp examination, we observed the presence of in-the-bag, multifocal, hydrophobic acrylic IOLs bilaterally. Specifically, calcified deposits within the substance of the IOL were observed.

CONCLUSION

To our knowledge, this is the first case of spontaneous calcification of a hydrophobic multifocal IOL and all cataract/refractive surgeons should be aware of this rare complication.

Anterior segment optical coherence tomography of intraocular lens opacification

Postoperative opacification of a hydrophilic acrylic intraocular lens (IOL) is an uncommon complication. A 57-year-old diabetic female who had undergone phacoemulsification with IOL implantation in her right eye 16 years back presented with diminution of vision in the same eye for 3 years. Significant IOL opacification was observed clinically and anterior segment optical coherence tomography clearly delineated the intraoptic deposits, sparing the haptics, and edges of the optic. IOL explant and exchange was performed leading to restoration of visual acuity to 6/9. Histochemical evaluation of the IOL confirmed that the hydrophilic acrylic IOL optic had calcium deposits.

A Survey of Intraocular Lens Explantation: A Retrospective Analysis of 23 IOLs Explanted during 2005

Purpose

To evaluate the indications, lens styles, perioperative findings, and results of intraocular lens (IOL) explantation or exchange performed in the authors department in 2005.

Methods

The retrospective analysis comprised 22 patients (23 eyes). Twenty-one eyes had previous phacoemulsification and IOL implantation, one eye secondary aphakic IOL, and one eye phakic IOL implantation. The indications for IOL explantation/exchange and perioperative complications were evaluated. The best-corrected visual acuity (BCVA) before and after surgery was compared.

Results

Time from initial surgery to explantation/exchange varied from 1 to 121 months, median value was 46 months. The IOLs were explanted using local anesthesia and in 21 eyes replaced with new lens. Indications for IOL removal were opacification of the IOL in 12 eyes, malposition of the IOL in 5 eyes, postoperative refractive error in 2 eyes, recurrent toxic anterior segment syndrome in 1 eye, pseudophakic dysphotopsia in 1 eye, endothelial cell loss in phakic anterior chamber IOL in 1 eye, and visual discomfort with intraocular telescopic lens in 1 eye. The mean BCVA (decimal scale) before and after IOL explantation/exchange was 0.562±0.279 and 0.627±0.276, respectively. There was no significant difference in visual acuity before and after IOL exchange (Wilcoxon test).

Conclusions

The most frequent indications for IOL explantation/exchange were opacification of the IOL and IOL malposition. Surgeries were uneventful in most cases. Final visual results have been largely good. Long-term follow-up of patients with various types of IOLs should be maintained.

Scanning Electron Microscopy and Energy Dispersive Spectroscopy Findings in Explanted Pmma and Hydrophilic Acrylic Intraocular Lenses

Purpose

To investigate the presence of calcium (Ca) aggregates influencing biocompatibility and the factors that affect calcium accumulation in explanted intraocular lenses (IOL) and to analyze the Ca distribution in an opacified hydrophilic acrylic lens.

Methods

Surface irregularities and aggregates of 13 IOLs were studied with scanning electron microscopy, and their relative concentrations with energy dispersive spectroscopy (EDS). Relationships of distribution between Ca and silicone (Si) and nitrogen (N) and between N and Si and Na, and the influence of Si on Ca accumulation and the effect of differences in lens material on the distribution of N, and the effect of endophthalmitis on the distribution of Ca were evaluated statistically. EDS analyses were performed on the surface and cross-section of the opacified lens.

Results

The statistically significant relationships between the distribution of Ca and N, and between the distribution of N and Na, the significant effect of Si on the Ca accumulation, significant relationship between endophthalmitis and the Ca accumulation in the aggregates were shown. The EDS analysis of the opacified IOL, Ca and P peaks were shown from the whole surface, Ca, O peaks were determined from cross-sections over a 70–80 μm distance.

Conclusions

In the aggregates influencing IOL biocompatibility, presence of proteins was determined to be more important than the presence of Si regarding the distribution of Ca, while the presence of Si affected the accumulation of Ca. Opacification, caused by the Ca accumulation within the lens, was found to result from Ca penetrating from lens pores.

Exchange Technique for Opacified Hydrophilic Acrylic Intraocular Lenses

Purpose

To report an exchange technique for opacified hydrophilic acrylic intraocular lenses (IOLs).

Methods

Twenty patients with two different types of opacified hydrophilic acrylic IOLs underwent IOL exchange by a single surgeon. Circumferential enlargement of the pre-existing capsulorrhexis was a critical step of the procedure, and resulted in expression of the IOL with minimal traction to the capsule. Implantation of an in-the-sulcus IOL followed. Surgical technique, complications, and visual outcome are discussed.

Results

Time from the initial cataract operation varied from 15 to 61 months (mean 30.5), and in all cases marked fibrosis was encountered. Eighteen patients had uncomplicated IOL exchange. Posterior capsule rupture occurred in two cases. Vision improved in 16 cases, remained unchanged in 3 cases, and deteriorated in 1 case.

Conclusions

IOL exchange of opacified hydrophilic acrylic IOLs is a particularly challenging procedure due to extensive fibrosis. Circumferential enlargement of the pre-existing capsulorrhexis significantly facilitates the mobilization of the IOL from its fibrous pocket, with the use of minimal forces. Thus, the risk of zonular dehiscence or posterior capsule rupture is minimized.

Intraocular Lens Calcification: Clinico-pathological Report of Two Cases and Literature Review

Purpose:

We report the clinicopathological features and surgical outcomes of two cases of intraocular lens (IOL) calcification along with a review of the current literature.

Case Report:

The first patient was a 53-year-old woman with diabetes mellitus (type 2) who underwent phacoemulsification with posterior chamber IOL insertion (PCIOL), and pars plana vitrectomy. Significant clouding of the IOL was first noted after 1.5 years, and the IOL was replaced with an Artisan lens. The second patient was a 22-year-old woman with Vogt-Koyanagi-Harada syndrome; she underwent a lensectomy, PCIOL, and pars plana vitrectomy. IOL opacification was first noted 4.5 years after the initial surgery and the IOL was extracted.

Conclusion:

The calcification of each IOL was confirmed by a pathologist. Further studies are required to determine the primary causes and mechanisms of the calcification of biomaterials including IOLs.

Acute clouding of trifocal lens during implantation: a case report

BACKGROUND

Intraoperative IOLs clouding of several kinds of hydrophilic acrylic intraocular lenses (IOLs) have been reported due to temperature changes. This phenomenon reported previously occurred in cold countries and during the winter months. However, no clinical case was reported about trifocal IOL opacification during operation. We report a case in which acute opacification of the optical region occurred simultaneously when AT LISA tri 839mp(Carl Zeiss) was implanted into the eye.

CASE PRESENTATION

A 79-year-old woman with a cortex and nucleus cataract was scheduled to undergo right eye phacoemulsification assisted by femtosecond technique. The trifocal lens (AT LISA tri 839mp), which is made of hydrophilic acrylic (25%) with hydrophobic surface properties, was chosen for implantation. As the IOL was implanted into the eye, it became cloudy immediately. Then it was replaced by another AT LISA tri 839mp, which was transferred from lens company outside, the same phenomenon was observed. These two lenses underwent the same temperature fluctuation from cold outside to operating room. Finally, a ZCB00 (Allergan) was implanted.

CONCLUSIONS

The acute intraoperative clouding of trifocal lens(AT LISA tri 839mp) results from fluctuation of temperature should be noticed.

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.

Akreos Adapt AO Intraocular lens opacification after vitrectomy in a diabetic patient: a case report and review of the literature

BACKGROUND

Postoperative optic opacification of hydrophilic acrylic intraocular lenses (IOLs) is an uncommon complication leading to IOL explantation. In the past decade, several studies reported that the granular deposits responsible for the opacification were probably calcium and phosphate salts; however, the exact mechanism causing calcification of IOLs is unknown. The aim of this study is to describe clinical and laboratory findings of a case of late postoperative opacification of an aspheric hydrophilic acrylic IOL (Akreos Adapt AO) after vitrectomy.

CASE PRESENTATION

A 60-year-old woman diagnosed with cataract and severe nonproliferative diabetic retinopathy (NPDR) underwent uneventful phacoemulsification and hydrophilic acrylic IOL (Akreos Adapt AO, Bausch & Lomb) implantation in both eyes. Seven months later, the woman came back with a complaint of blurry vision in the left eye. Fundus examination revealed vitreous hemorrhage in the left eye veiling the retinal detail. A 23-gauge vitrectomy with endolaser treatment was performed in the left eye. Ten months after the vitrectomy, the patient complained of decreased visual acuity in the left eye again. On slit-lamp examination, we observed a well circumscribed centrally and paracentrally located opacification within the pupillary area localized to the anterior surface of the IOL. The IOL was explanted from the left eye together with the capsular bag, and an iris-claw lens (Artisan Aphakia OPHTEC) was implanted. The explanted IOL was examined under pathological evaluation (alizarin red method).

CONCLUSIONS

IOL opacification is a rare event. We described a case of postoperative opacification of the Akreos Adapt AO IOL after vitrectomy in a patient with proliferative diabetic retinopathy and found the deposits on the anterior surface of the IOL consisted of calcium aggregates. Given the higher frequency of postoperative opacification observed in diabetic patients, hydrophilic acrylic IOLs should be used with caution in patients with diabetes.

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.

Management of retinoblastoma: opportunities and challenges

Nano-delivery systems have significantly evolved over the last decade for the treatment of cancer by enabling site-specific delivery and improved bioavailability. The widely investigated nanoparticle systems are biodegradable polyesters, dendrimers, liposomes, mesoporous silica and gold nanoparticles. These particles when conjugated with different targeting motifs enhance the therapeutic efficiency of the drug molecules and biocompatibility. However, the application of such systems towards the treatment of retinoblastoma (RB), a rapidly spreading childhood eye cancer, still remains in its infancy. Nanoparticle-based systems that have been investigated for RB therapy have displayed improved drug delivery to the most restricted posterior segment of the eyes and have increased intra-vitreal half-life of the chemotherapy agents highlighting its potential in treatment of this form of cancer. This review focuses on the challenges involved in the treatment of RB and highlights the attempts made to develop nano-dimensional systems for the treatment of RB.

Calcification in hydrophilic intraocular lenses associated with injection of intraocular gas

PURPOSE

To report a distinct type of calcification in hydrophilic intraocular lenses in complicated, traumatized eyes with a history of intraocular gas use.

DESIGN

Observational case series.

METHODS

Three cases of hydrophilic intraocular lens (IOL) opacification confined to the pupillary area are reported from clinical practice in London, UK. Clinical details and analysis of the explanted intraocular lenses are provided with environmental scanning electron microscopy images and x-ray energy-dispersive spectroscopy results.

RESULTS

All cases were associated with use of intraocular gas in complicated traumatized eyes, and had central areas of IOL opacification over the pupillary zone, confined to the anterior surface of the IOL. Analysis of the lenses showed the opacified areas to be composed of calcium and phosphate.

CONCLUSION

The areas of opacification in all 3 hydrophilic IOLs were attributable to calcification. We postulate that intraocular gas use and the altered blood-aqueous barrier of these complicated traumatized eyes co-act to trigger secondary IOL calcification. Further experimental testing is needed to confirm this clinical association.