Oral zinc and the second eye in age-related macular degeneration

To investigate the short-term effect of oral zinc substitution on the development of age-related macular degeneration in the second eye of patients with an exudative form of the disease in the first eye.

A 2-year, double-masked, randomized, placebo-controlled study including 112 white patients with age-related macular degeneration and exudative lesions (choroidal neovascularization, pigment epithelial detachment, or both) in one eye and a visual acuity of better than 20/40 and macular degeneration without any exudative lesion in the second eye was performed. Patients received either 200 mg of oral zinc sulfate or placebo once daily for 24 months. The main outcome parameters were visual acuity, contrast sensitivity, color discrimination, and retinal grating acuity, as well as serum levels of zinc and copper, red blood cell count, hemoglobin, and morphologic changes detected by grading of monochrome fundus photographs and fluorescein angiograms.

In the treatment group, the mean zinc serum level increased significantly (P < 0.0001) from 79 +/- 10 micrograms/dl to 108 +/- 26 micrograms/dl compared to no change (82 +/- 16 micrograms/dl to 85 +/- 10 micrograms/dl) in the placebo group. Serum levels of copper, hemoglobin, and red blood cell count did not change significantly in either group. A choroidal neovascular membrane (CNV) was detected in 14 patients during the treatment period (nine in the treatment group, five in the placebo group). Seven additional patients (three in the treatment group, four in the placebo group) experienced visual loss caused by CNV, and in two patients (one in each group), serous pigment epithelial detachment developed without angiographic evidence of CNV after the end of treatment, during a mean additional follow-up time of 20.8 +/- 8.2 months. In eyes in which exudative lesions did not develop, there was no significant change in any of the functional parameters during the 24-month treatment period, but there was a significant increase in the nonexudative alterations (drusen size, drusen confluence, hyperpigmentation, and focal degeneration of the retinal pigment epithelium) in both groups.

Oral zinc substitution has no short-term effect on the course of age-related macular degeneration in patients who have an exudative form of the disease in one eye.