Electroretinographic findings in panretinal photocoagulation for diabetic retinopathy. A randomized study with blue-green argon and red krypton lasers

Abstract

A total of 16 patients (16 eyes) with type II diabetes mellitus and proliferative retinopathy were studied electroretinographically before panretinal photocoagulation, during intervals between the treatment sittings, within 36 h of the final treatment and 4 months after its conclusion. Treatments were carried out with blue-green argon (eight eyes) and red krypton (eight eyes) lasers; the type of laser was randomly chosen. The analysis of the results obtained showed a significant and marked reduction in peak amplitudes of both a- and b-waves in photopic and dark-adapted conditions as early as between the multiple treatments. Electroretinograph (ERG) tracks did not change significantly at subsequent checks. Amplitude reductions were higher for scotopic b-waves and in eyes that had the less altered baseline tracks. Implicit times did not change significantly. The type of laser used did not significantly influence ERG evolution.