Visual evoked potential latency and contrast sensitivity in patients with posterior chamber intraocular lens implants.

An electrophysiological investigation of visual evoked potential (VEP) latency and contrast sensitivity was performed in a group of 13 patients who had undergone extracapsular cataract surgery with posterior chamber lens implantation. In spite of good postoperative visual acuity, abnormalities were detected in nine of the group (69%). This study suggests that, even with successfully implanted lenses, there may be a reduction in visual function which could be the result of altered transmission through the plastic lenticulus or fibrosis of the posterior lens capsule, and/or subtle changes in retinal architecture, not observed ophthalmoscopically.

Platelet aggregation and retinal microangiopathy in diabetes and hypertension.

Platelet aggregation studies were done in 10 cases of diabetes with and without retinopathy and 7 cases of hypertensive retinopathy with adenosine diphosphate (ADP) and adrenaline (ADR). It was observed that the rate and degree of aggregation was significantly increased in the retinopathy group both with ADP and ADR. A significant alteration in the latent period was found with ADP, whereas no such change was found with ADR. It is proposed that the increased platelet reactivity in retinal microangiopathy could be due to different mechanisms. Increased sensitivity of the platelets to ADP resulting in the rapid inductive phase of aggregation together with accelerated intrinsic ADP release in diabetic retinopathy may cause hyperaggregation of platelets. Hyperaggregation in hypertensive retinopathy, however, may occur due to accelerated ADP release only. Platelet metabolism supporting the release reaction is altered in both.