Light scattering levels from intraocular lenses extracted from donor eyes

Abstract

Purpose: To assess light scatter levels of intraocular lenses (IOLs) extracted from donor eyes to understand straylight elevation documented earlier in pseudophakic population studies and identify potential sources of light scattering in IOLs.

Setting: Rotterdam Ophthalmic Institute, Rotterdam, the Netherlands.

Design: Experimental study.

Methods: Light scattering in 74 donor IOLs was measured with the C-Quant device adapted for in vitro analysis of IOLs. Straylight was assessed at a 2.5-degree and 7.0-degree scatter angle, and results were compared with the straylight of a 20-year-old crystalline lens, a 70-year-old crystalline lens, and a lens with cataract. To identify potential changes to the IOL material, the IOLs were examined with a light microscope and a slitlamp.

Results: At 2.5 degrees and 7.0 degrees, the straylight parameter was 5.78 deg²/steradian (sr) ± 4.70 (SD) and 5.06 ± 4.01 deg²/sr, respectively. Forty-one percent of IOLs showed lower straylight than the 20-year-old lens. In 14%, the scattering intensity was higher than in the 70-year-old lens; none showed straylight comparable to that of the cataractous lens. Increased straylight was associated with surface deposits, snowflake-like degeneration, and glistenings. The incidence of IOL-related complications differed between the IOL groups.

Conclusions: Microscopic structural alterations of IOLs play a major role in straylight elevations in pseudophakic eyes. A clear correlation with degeneration and/or alteration of implanted IOLs was found. Although these IOL-related complications would likely not affect visual acuity, they give rise to straylight and thus can cause disability glare and other symptoms.