THE ROLE OF LIGHT SCATTER IN THE DEGRADATION OF VISUAL PERFORMANCE BEFORE AND AFTER ND-YAG CAPSULOTOMY

The aim of this study was to determine whether capsulotomy size influe nces visual performance. Snellen visual acuity and forward light scatt er (light scattered towards the patient's retina, but out of the focus sed retinal image) measurements using simple computer graphics based o n van den Berg's technique were used to measure visual performance. Tw elve patients were studied: 4 had small central capsulotomies through undilated pupils and 8 had wide capsulotomies through dilated pupils. The two groups were matched for age and pre-laser Snellen acuity. Foll owing treatment, both groups had equal improvements in Snellen acuity. There was only a significant (p<0.001) improvement in forward light s catter readings in the group who received wide capsulotomies. Measurem ents of forward light scatter are more sensitive than Snellen acuity t esting in demonstrating loss of visual performance in patients with me dia opacities. It is recommended that pupils are dilated prior to Nd:Y AG capsulotomy if forward light scatter from capsule remnants and the consequent glare disability are to be minimised.