Straylight measurements in pseudophakic eyes with natural and dilated pupils: one-year follow-up

To compare the amount of straylight in natural pupils and dilated pupils in pseudophakic eyes 6 weeks and 1 year after cataract extraction.

Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.

This study evaluated patients with bilateral age-related cataract who had cataract surgery with implantation of an aspheric Tecnis ZA9003 or spherical Sensar AR40e intraocular lens (IOL). Straylight measurements were performed with a C-Quant straylight meter 6 weeks after surgery (with natural pupils) and 1 year after surgery (with natural and dilated pupils) in a randomly chosen eye. Retroillumination photographs of dilated pupils were taken to document posterior capsule opacification. The main outcome variable for straylight measurements was the logarithmic straylight parameter, log(s).

Twenty-two patients were evaluated. There was a statistically significant decrease in straylight in a natural pupil between 6 weeks (mean 1.44 log[s]) and 1 year (mean 1.30 log[s]) postoperatively (P = .012). The straylight parameter was greater after dilation (mean 1.48 log[s]) than with a natural pupil (1.29 log[s]) at 1 year (P = .012). This difference was greater when more anterior capsule was visible in the pupillary area (P = .031).

Straylight decreased significantly in the first year after cataract surgery. Furthermore, it increased with increasing pupil size, which was associated with a capsulorhexis smaller than the pupil. This indicates the capsulorhexis should be as large as possible to prevent straylight, especially under low-luminance conditions when the pupil is large.