July 2019

ASCRS NEWS

The impact of glistenings on the optical quality of a hydrophobic acrylic intraocular lens


Jan Weindler, MD, Grzegorz Labuz, PhD, Timur Yildirim, MD, Tamer Tandogan, MD, Ramin Khoramnia, MD, Gerd Auffarth, MD

J Cataract Refract Surg. 2019;45(7):1020–1025.
Purpose: To study the impact of glistenings on the optical quality of a hydrophobic acrylic intraocular lens (IOL).
Setting: David J. Apple Laboratory, Heidelberg, Germany
Design: An in vitro laboratory study.
Methods: An accelerated-aging protocol was used to induce glistenings (microvacuoles) in 38 SA60AT (Alcon) IOLs. The IOLs were subjected to 45 degrees C and then cooled to 37 degrees C. Image analysis of light-microcopy photographs determined the number and size of microvacuoles. A classification was applied based on the glistening number per mm2: grade 0 (none), grade 1 (1–100), grade 2 (101–200), grade 3 (201–500) and grade 4 (more than 500). An optical bench was used to measure the IOL’s modulation transfer function (MTF) and Strehl ratio, to evaluate the impact of glistenings on image quality.
Results: Glistenings were observed in all IOLs. The mean glistening number ± standard deviation [MV/mm²] in grade 14 was 74±12.7 (grade 1), 142±22.2 (grade 2), 297±76.2 (grade 3), and 1509±311.9 (grade 4). The mean glistening size was 13.28±3.85 μm in grade 1, 15.88±2.08 μm in grade 2, 16.85±3.23 μm in grade 3 and 15.27±2.25 μm in grade 4. Statistical analysis showed that grades 1–3 did not change the optical quality, however, in grade 4 the MTF and the Strehl ratio were significantly affected.
Conclusions: We demonstrated that a limited number of glistenings (<500 MV/mm2) have no impact on the image quality. Although a statistically significant deterioration of the MTF and the Strehl ratio was observed in grade 4, the effects found were small and are unlikely to affect the visual quality.

The impact of glistenings on the optical quality of a hydrophobic acrylic intraocular lens The impact of glistenings on the optical quality of a hydrophobic acrylic intraocular lens
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2019-07-01T08:16:30Z
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