Calcification of hydrophilic acrylic intraocular lenses following secondary surgical procedures in the anterior and posterior segments

FIL SSF intraocular lens opacification after gas tamponade: A case series

PURPOSE

To report three cases of postoperative opacification of sutureless scleral-fixed hydrophilic intraocular lens (FIL SSF IOL, Soleko, Italy) after gas tamponade. Two cases occurred after pars plana vitrectomy and one case after Descemet membrane endothelial keratoplasty.

CASE REPORT

Two diabetic patients underwent a FIL SSF IOL implantation after posterior capsular rupture during cataract surgery. Rhegmatogenous retinal detachment (RRD) was observed in one patient during the initial surgery. A second patient developed a RRD five months after surgery. Both RRDs were treated with pars plana vitrectomy and perfluoroethane (C2F6) gas tamponade. A few days after the surgery, C2F6 was observed in the anterior chamber of both patients. Two months after gas tamponade, opacification of the anterior surface of the IOL was observed. The third patient was a 74-year-old woman, who underwent a combined Descemet membrane endothelial keratoplasty (DMEK) and FIL SSF IOL implantation. Two rebubblings with sulfur hexafluoride (SF6) retreatments were required due to corneal graft detachment. One month later, an opacification of the anterior surface of the IOL was observed. Explantation with implantation of iris-claw IOL was decided, which resulted in an improvement of BVCA. Analysis of the IOL showed a positive Von Kossa staining, indicating calcification of the IOL. We performed a review of all the cases of FIL SSF IOL implantation in our centers. The overall rate of FIL SSF IOL opacification was 2.1% (3/140). Amongst patients treated with gas tamponade, the rate of opacification was 27.3% (3/11). Although FIL SSF IOL implantation appears to be an effective option for the treatment of aphakia, caution should be exercised regarding the risk of opacification following gas tamponade, especially since these patients are at risk of retinal detachment.

Opacification of Hydrophilic Acrylic Intraocular Lenses: Overview of Laboratory Methods for Histological Analysis and Replication of IOL Calcification

Opacification of intraocular lenses (IOLs) due to material changes is a serious complication that can compromise the good visual outcomes of uncomplicated cataract surgery. In hydrophobic acrylic IOLs, opacification can result from glistening formation, while in hydrophilic acrylic IOLs, there is a risk of calcification due to the formation of calcium phosphates within the polymer. Over time, various methods have been developed to investigate calcification in hydrophilic acrylic IOLs. The aim of this article is to provide an overview of standard histological staining and models used to simulate IOL calcification. Histological staining can be used to detect calcification and assess the extent of crystal formation. The development of in vivo and in vitro replication models has helped to identify the underlying pathomechanisms of calcification. In vivo models are suitable for assessing the biocompatibility of IOL materials. Bioreactors as an in vitro model can be used to investigate the kinetics of crystal formation within the polymer. The replication of IOL calcification under standardized conditions using electrophoresis allows for the comparison of different lens materials with respect to the risk of calcification. The combination of different analytical and replication methods can be used in the future to further investigate the pathomechanisms of calcium phosphate crystal formation and the influence of risk factors. This may help to prevent calcification of hydrophilic acrylic IOLs and associated explantation and complications.

Late postoperative opacification of a new type hydrophilic acrylic intraocular lens

Background

To report the clinical consequences and laboratory characteristics of late postoperative opacification of a hydrophilic acrylic intraocular lens (US-860UV IOL) as well as the prognosis of IOL replacement.

Methods

Forty medical records (42 eyes) of patients with US-860UV IOL opacification reporting decreased or lost vision who underwent IOL explantation between 2017 and 2019 were reviewed. Explanted IOLs were analyzed by slit-lamp examination, confocal microscopy, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) at the Shandong Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University, and Qingdao University of Science and Technology, Qingdao, China.

Results

The mean age of the 40 patients was 74.83 ​± ​7.57 (63-92) years. The mean interval between cataract surgery and diagnosis of opacification was 32.38 ​± ​8.76 (17-48) months. Systemic diseases were found without statistical correlations, the most frequent being arterial hypertension, coronary heart disease, and diabetes mellitus. Visual acuity improved from 1.42 ​± ​1.03 to 0.31 ​± ​0.16 (logMAR) after IOL replacement. SEM, EDS and alizarin red staining showed uniformly distributed, diffuse, milk-white opacification, with calcium and phosphorus deposits on the optic and haptic surfaces that could be dissolved in 1% HCl.

Conclusions

Calcium and phosphorus deposition was the main cause of hydrophilic acrylic US-860UV IOL opacification. IOL replacement can safely and effectively improve the visual acuity of patients.

Visual and Refractive Outcomes Following Exchange of an Opacified Multifocal Intraocular Lens

Purpose

To assess the visual and refractive outcomes following exchange of an opacified multifocal intraocular lens (IOL).

Patients and Methods

A consecutive series of 37 eyes (31 patients) that underwent IOL exchange between November 2015 and May 2021 were included in this study. The indication for surgery in all cases was opacification of a multifocal IOL. Outcome measures included design and anatomical location of the secondary IOL, intraoperative and postoperative complications, visual acuity and refractive accuracy.

Results

An opacified Lentis Mplus multifocal IOL was explanted from all eyes and replaced with a monofocal IOL in 21 eyes (57%) and multifocal IOL in 16 eyes (43%). Secondary IOLs were implanted in the capsular bag or sulcus or were iris-fixated. IOL exchange was performed at a mean interval of 7 years after the primary surgery. Anterior vitrectomy was required for vitreous prolapse in 9 eyes (24%). Mean corrected distance visual acuity (CDVA) postoperatively was −0.02 ± 0.08 logMAR for eyes with a monofocal secondary IOL and 0.02 ± 0.08 logMAR for eyes with a multifocal secondary IOL. Mean refractive prediction error was −0.57 ± 0.67 D in the multifocal-monofocal group and −0.33 ± 0.59 D in the multifocal–multifocal group.

Conclusion

An opacified multifocal IOL can be exchanged for a monofocal or multifocal IOL, depending on available capsular support and the patient’s desired refractive outcome. Vitreous prolapse requiring anterior vitrectomy is the most common intraoperative complication. An improvement in visual acuity and a low postoperative complication rate were achieved in this cohort of patients.

Development of a standardized in vitro model to reproduce hydrophilic acrylic intraocular lens calcification

Opacification through calcification of hydrophilic acrylic intraocular lenses (IOL) is a severe complication after cataract surgery. Causing symptoms that range from glare through to severe vision loss, the only effective therapy is explantation of the opacified IOL so far. Although IOL calcification is a well-described phenomenon, its pathogenesis is not fully understood yet. The purpose of the current study was to develop a laboratory model to replicate IOL calcification. Calcification could be reproduced using a horizontal electrophoresis and aqueous solutions of calcium chloride and disodium hydrogen phosphate. The analysis of the in vitro calcified IOLs was performed using light microscopy, Alizarin Red and Von Kossa staining, scanning electron microscopy, energy dispersive x-ray spectroscopy and electron crystallography using transmission electron microscopy and electron diffraction. The presented laboratory model could be used to identify hydrophilic IOLs that are at risk to develop calcification and to assess the influence of associated risk factors. In addition, it can serve as a research tool to further understand this pathology.

Analysis of opacification patterns in intraocular lenses (IOL)

Objective

Intraocular lens (IOL) opacification may cause severe visual impairment. The pathogenesis remains unclear. The aim of this study was to analyse opacification patterns in different IOLs. Therefore, this multicentre, retrospective, observational study was conducted at Ludwig-Maximilians-University, Munich, Germany and University-Hospital Basel, Switzerland.

Methods and analysis

In this study, 75 opacified IOLs were identified and classified after extraction. Macroscopical photo documentation, light and electron microscopic analysis were done.

Results

68 acrylic-hydrophilic single-piece-IOLs, 1 acrylic-hydrophilic 3-piece-IOL, 6 acrylic-hydrophobic 3-piece-IOLs were extracted. The dataset comprised IOLs known for opacification and IOLs not having been reported yet. 67 IOLs showed a fine-granular and 8 IOLs a crust-like opacification pattern. According to literature, 62 of the fine-granular opacified IOLs were graded into type 1 (processing/packaging-induced primary opacification) and 13 into type 2 (secondary opacification of unknown aetiology). The anterior surface of the IOLs was affected in all 75 IOLs, the posterior surface only in 23 cases. Of all 67 fine-granular IOLs, 43 had a central defect and 21 had a zone without opacification (clear islet).

Conclusion

In our series, the morphology of IOL opacification did not follow the existing pathogenetic classification that strictly discriminates between primary and secondary causes. Fine-granular IOL opacification occurs with similar patterns in both type 1 and type 2 IOL opacification, while a crust-like pattern was only detected in type 2 IOL opacifications. Consequently, susceptibility of an IOL to opacification is caused by a multifactorial combination of material and processing properties as well as individual (pathological) conditions of the patient.

Physicochemical Analysis of Sediments Formed on the Surface of Hydrophilic Intraocular Lens after Descemet's Stripping Endothelial Keratoplasty

An intraocular lens (IOL) is a synthetic, artificial lens placed inside the eye that replaces a natural lens that is surgically removed, usually as part of cataract surgery. The opacification of the artificial lens can be related to the formation of the sediments on its surface and could seriously impair vision. The physicochemical analysis was performed on an explanted hydrophilic IOL and compared to the unused one, considered as a reference IOL. The studies were carried out using surface sensitive techniques, which can contribute to a better understanding of the sedimentation process on hydrophilic IOLs’ surfaces. The microscopic studies allowed us to determine the morphology of sediments observed on explanted IOL. The photoelectron spectroscopy measurements revealed the presence of organic and inorganic compounds at the lens surface. Mass spectroscopy measurements confirmed the chemical composition of deposits and allowed for chemical imaging of the IOL surface. Applied techniques allowed to obtain a new set of information approximating the origin of the sediments’ formation on the surface of the hydrophilic IOLs after Descemet’s stripping endothelial keratoplasty.