Copper and zinc levels after external damage by laser photocoagulation to the retinal pigment epithelium. Preliminary reports.

Several reports have appeared in the literature linking abnormalities in the Retinal Pigment Epithelium (RPE) related with changes in the metabolism of copper and zinc. It has not been yet elucidated if the changes in the metabolism of these metals are secondary to a progressive disease that affects the RPE, or the changes found in this retinal layer are a manifestation of a basic metabolic disease. In the present study a group of 22 diabetic patients with different degree of retinopathy was evaluated. Eleven of these patients underwent laser treatment, and blood and urine copper and zinc were assessed prior to the treatment and at intervals of one day, one week and one month post treatment. All these patients were compared with a control group. We found a rise in the mean concentration of copper and zinc in serum, and zinc in the urine, in those patients who underwent more than 600 laser applications. The significance of these findings and their relationship to the RPE is discussed.