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Contributions of the Capsulorrhexis to Straylight
Ivanka J. E. van der Meulen, MD;
Leonore A. Engelbrecht, MD;
Tom C. T. Van Riet;
Ruth Lapid-Gortzak, MD;
Carla P. Nieuwendaal, MD;
Maarten P. Mourits, MD, PhD;
Thomas J. T. P. van den Berg, PhD
Arch Ophthalmol. 2009;127(10):1290-1295.
Objectives To quantify the effect of the capsulorrhexis on straylight and to determine optimal capsulorrhexis size.
Methods Fifty-six pseudophakic eyes with intact capsulorrhexis were included in the study. Straylight was measured with a straylight meter before and after pupil dilation. Capsulorrhexis and pupil diameter were measured and opacity of the anterior capsule was graded (on a scale of 0-5) with the slitlamp. Capsulorrhexis size and opacity were compared with the difference in straylight values between natural and dilated pupils.
Results The mean capsulorrhexis diameter was 4.5 mm (range, 2.9-6.2 mm). Most anterior capsular rims were opaque in the area of contact with the intraocular lens (62.5% higher than grade 1). Mean straylight before pupil dilation was logs=1.25 (range, 0.68-2.13), which increased to 1.46 (range, 0.88-2.22) after pupil dilation, which corresponds to a 62% increase (P <.001). The effect of capsulorrhexis size and opacity on the increase in straylight in scotopic conditions can be quantified by the following formula:  s = 19 x (grading of anterior capsular rim) x (fraction of pupil area covered by rhexis).
Conclusions The influence of size and opacity of the capsulorrhexis via straylight is described in a quantitative model. Capsulorrhexis size must be greater than 4 mm to prevent functional problems at night.
Author Affiliations: Department of Ophthalmology, Academic Medical Center (Drs van der Meulen, Engelbrecht, Lapid-Gortzak, Nieuwendaal, and Mourits), and Netherlands Institute for Neuroscience, Netherlands Royal Academy (Mr Van Riet and Dr van den Berg), Amsterdam.
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