Effect of Posterior Capsule Opacification and Anterior Capsule Contraction on Visual Function

Abstract

In this chapter, a study done to examine the effect of (1) the size of Nd:YAG laser posterior capsulotomy for posterior capsule opacification (PCO) and (2) anterior capsule contraction (ACC) on visual function is described. (1) Eyes with PCO first underwent posterior capsulotomy smaller than pupillary size, after which the capsulotomy was secondarily enlarged to greater than pupillary size. Visual acuity (VA), contrast VA, and that with glare (glare VA) under photopic and mesopic conditions were measured after the small and large capsulotomies (in the same eyes). After enlargement, the mean capsulotomy area increased from 4.8 to 15.3 mm2. Mean corrected-distance VA (CDVA) did not improve significantly after enlargement, but photopic contrast VA and glare VA at moderate-to-low-contrasts and mesopic contrast VA and glare VA improved significantly. (2) Eyes with ACC underwent Nd:YAG laser anterior capsulotomy. The anterior capsule opening area was measured before and after capsulotomy and was correlated with VA and contrast sensitivity. The mean anterior capsule opening area increased from 8.2 to 18.0 mm2 after capsulotomy. The mean contrast sensitivity at most visual angles improved significantly after capsulotomy, although CDVA did not. The anterior capsule opening area before capsulotomy was correlated significantly with contrast sensitivity, but not with CDVA. In conclusion, in eyes with PCO, contrast sensitivity was worse with a small capsulotomy than with a large capsulotomy, suggesting that a capsulotomy larger than the pupil is necessary to restore contrast sensitivity. ACC impairs significantly contrast sensitivity in proportion to the opening area, but does not worsen CDVA markedly.