Comparison of methods to experimentally induce opacification and elasticity change in ex vivo porcine lenses

At the moment, cataract, which is the opacification of the eye’s lens, can only be treated by surgery. In order to develop and test new pharmacological treatment strategies for the disease, there is a need for an appropriate in vitro model using ex vivo animal lenses. In this study, porcine lenses were incubated in either culture medium, glucose, triamcinolone acetonide, sodium chloride, hydrogen peroxide, sodium selenite, neutral buffered formalin, or were exposed to microwave heating to experimentally induce lens opacification. Changes in the lens morphology, weight, size, and elasticity were monitored 7 days after treatment. The fastest induction of dense opacification was seen in lenses exposed to sodium chloride, neutral buffered formalin, and microwave heating. No change in the size and weight of the lenses were detected, whereas loss in elasticity could be detected in lenses treated with formalin solution or microwave heating. Thus, neutral buffered formalin- and microwave-treated ex vivo porcine lenses seem to be a suitable model for mature cataracts, whereas hypertonic sodium chloride may be useful for studies on osmolarity-induced lens opacification.

Instillation of Ophthalmic Formulation Containing Nilvadipine Nanocrystals Attenuates Lens Opacification in Shumiya Cataract Rats

We developed ophthalmic formulations based on nilvadipine (NIL) nanocrystals (NIL-NP dispersions; mean particle size: 98 nm) by using bead mill treatment and investigated whether the instillation of NIL-NP dispersions delivers NIL to the lens and prevents lens opacification in hereditary cataractous Shumiya cataract rats (SCRs). Serious corneal stimulation was not detected in either human corneal epithelial cells or rats treated with NIL-NP dispersions. The NIL was directly delivered to the lens by the instillation of NIL-NP dispersions, and NIL content in the lenses of rats instilled with NIL-NP dispersions was significantly higher than that in the ophthalmic formulations based on NIL microcrystals (NIL-MP dispersions; mean particle size: 21 µm). Moreover, the supply of NIL prevented increases in Ca2+ content and calpain activity in the lenses of SCRs and delayed the onset of cataracts. In addition, the anti-cataract effect in the lens of rats instilled with NIL-NP dispersions was also significantly higher than that in NIL-MP dispersions. NIL-NPs could be used to prevent lens opacification.

Trimetazidine Topical Delivery Prevents Carrageenan Induced Retinal Damage and Glucose Induced Lens Opacification by Decreasing Drop of Protein Level

Carrageenan induced oxidative stress develops retinal damage and increases lipid peroxidation. Glycation of the lens proteins increases modified proteins and may affect the lens structural integrity and opacification, after increasing glucose concentration in the lens. Trimetazidine (TZ) has been reported to have cytoprotective anti-ischaemic activity after systemic administration in an animal model. Trimetazidine ophthalmic film formulation has been prepared using HPMC as the hydrogel-forming polymer. The cytoprotective role of trimetazidine has been studied on carrageenan-induced retinal damage of rat eye by histologicaland Malondialdehyde (MDA) assay applying sterilized film formulation. Trimetazidine solution was used in combination with a high concentration of glucose solution (55 mM) for examining the protective effect from cataract formation. Formulation showed controlled and extended ophthalmic permeation of the drug for about 5 h. Damage of retinal cells in the ganglionic layer has been decreased significantly in the trimetazidinetreated group. Drug treated control group also showed significant disappearance of pyknotic cells. The addition of trimetazidine to the glucose medium practically retarded the lens opacification by reducing the over-production of reactive oxygen species (ROS) in increased sugar concentration. Presence of trimetazidine probably decreased the drop of protein level in lens under stressed condition and greater preventive effect has been noticed with TZ concentration of 240 µg/ml rather than 120 µg/ml. Trimetazidine ophthalmic film formulation could prevent retinal damage and cataract formation.

Lens densitometry for assessment and prediction of cataract progression after pars plana vitrectomy with C3F8-gas for retinal detachment

Purpose Lens opacification is a common complication after pars plana vitrectomy (PPV) and knowing its progression would facilitate consulting patients. The purpose of this study was to evaluate a quantitative model for lens-status-monitoring after PPV with C3F8 gas. Our model was evaluated in rhegmatogenous retinal detachment (RRD) patients of various age and lens densitometry (LD). Methods Data between March 2018 and March 2020 were evaluated retrospectively. LD measurements of the PentacamHR® Nucleus Staging mode (PNS) were used to quantify lens opacification over time. A mixed-effect regression model was designed, to enable LD predictions at any time postoperatively. Calculations were based on patient’s age and baseline LD as dependent variables. Six patients were randomly excluded during model development, to be used for testing its power afterwards. Results 34 patients (male 19 [55.9%], female 15 [44.1%]) matched the inclusion criteria. Average age was 58.5 years (32–77;±4.3) and average follow-up was 7.2 months (3,4–23.1;±1,8). Mean baseline LD of the treated and fellow eye before surgery were 10.9% (8.7%-14.8%;±0.8) and 10.7% (8.5%-14.1%;±0.6), respectively. Using our prediction model, LD values for the six pre-selected patients closely match the observed data with an average deviation of 1.07%. Conclusions Evaluation of age and baseline LD using a mixed-effect regression model might predict cataract progression in RRD patients treated with PPV and C3F8-gas. Such a tool could be considered during cataract surgery consultation in these patients.

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.