Glistening formation in a new hydrophobic acrylic intraocular lens

Abstract

Background: The formation of fluid-filled microvacuoles, termed glistenings, is a common complication of intraocular lenses (IOLs) made from hydrophobic acrylate. Using our well-established in-vitro laboratory method, we evaluated a new IOL material's resistance to glistening formation. Methods: An in-vitro stress test for glistening induction was performed on 20 samples of hydrophobic acrylic IOLs: ten of the new Eyecryl ASHFY600 (Biotech Vision Care, Ahmedabad, India) compared with ten samples of AcrySof IQ SN60WF (Alcon, Fort Worth, USA). The number of microvacuoles per square millimetre (MV/mm 2) was evaluated in five sections of each IOL. The results for each model were compared and rated on a modified Miyata Scale for grading glistening severity. Results: In all cases, glistening number was higher in the central section of the IOL optic than in the periphery. Mean number of MV/mm 2 was highest in the central part of the AcrySof IQ SN60WF, with 41.84 (±27.67) MVs/mm 2. The lowest number of glistenings was found in the five sections of the Eyecryl ASHFY600 with 0.52 (±0.24) MVs/ mm 2. Mean value of the Eyecryl ASHFY600 IOL, using the Miyata Scale, was Zero. Conclusion: In this in-vitro laboratory study, the new hydrophobic acrylic IOL showed a high resistance to microvacuole formation. Results from this in-vitro study suggest that glistening numbers will be low in clinical use in the Eyecryl ASHFY600.

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

“…Each IOL was mounted on a heated stage at 37 °C for optical microscopy and a photographic record. A 14-fold magnification was selected to center the IOL on a grid, before a photograph of the central IOL optic was taken in 90-fold magnification [ 12 ]. ImageJ (1.49v) software was used to obtain the glistening number [ 12 , 25 ].…”

“…A 14-fold magnification was selected to center the IOL on a grid, before a photograph of the central IOL optic was taken in 90-fold magnification [ 12 ]. ImageJ (1.49v) software was used to obtain the glistening number [ 12 , 25 ]. The number of glistenings was given in mean microvacuoles per square millimeter (MV/mm 2 ) (± SD) and compared to the modified clinical (Miyata) glistening grading system, with grade 0 (< 50 MVs/mm 2 ), grade 1 (50–100 MVs/mm 2 ), grade 2 (100–200 MVs/mm 2 ) and grade 3 (> 200 MVs/mm 2 ) [ 16 ].…”

“…The impact of glistenings on patients’ visual function lies mainly in increased intraocular light scattering, which is linearly dependent of the number and size of MV [ 5 ]. While different experimental setups have been developed to create this material change in vitro and simulate an accelerated aging process, one approach that involves alternating heating and cooling has been shown to create valid and repeatable results simulating the IOL aging within the human eye [ 5 , 11 , 12 ]. Since these initial observations, IOL manufacturers have aimed to reduce the tendency toward glistenings by improving the lens production processes [ 11 ].…”

Eintrübung von Intraokularlinsen

“…Da es im klinischen Setting bis zum Nachweis von Glistenings Monate bis Jahre dauern kann, sind verschiedene In-vitro-Modelle von Bedeutung, mit deren Hilfe diese Pathologie im Labor künstlich erzeugt und untersucht werden kann [2]. Ein Modell, das durch Temperaturunterschiede Glistenings erzeugt, wird dabei besonders häufig verwendet [15]. Die unterschiedlichen IOL-Materialien unterscheiden sich hinsichtlich der Anzahl und Anordnung von Glistenings z. T. deutlich voneinander.…”

Quantitative evaluation of microvacuole formation in five intraocular lens models made of different hydrophobic materials

“…The most accepted theory regarding glistenings’ formation is that water entering the material collects in low polymer density areas (pockets). As the pockets enlarge over time, vacuoles might form which are visible to the clinician at the slit-lamp [ 5 , 6 ]. Glistenings are 1 to 25 μm in size; vacuoles of less than 200 nm in diameter distributed up to 120 μm underneath the IOL surface are termed subsurface nanoglistenings (SSNGs) [ 7 ].…”