The acute effect of oral acetazolamide on macular blood flow.

Acetazolamide has been shown to be beneficial in the treatment of macular edema. To investigate whether this effect is associated with changes in the retinal circulation, the acute effect of oral acetazolamide on macular blood flow was studied in 20 healthy volunteers. The blue-field simulation technique, a noninvasive method enabling the quantitation of the number (N) and mean velocity (Vm) of leukocytes flowing in the subject's own macular capillaries was used in this study. On two different occasions, separated by 3 or more days, 20 subjects adjusted Vm and N of computer-simulated leukocytes moving on a video screen to match those of their own entoptically perceived leukocytes before and 3 hr after a double-blind, randomized administration of 500 mg acetazolamide or placebo capsules. Ten trials were done, and the velocities were averaged. After acetazolamide ingestion, there was a nonsignificant average change from baseline in Vm (2.5 +/- 23% [+/- one standard deviation]; P greater than 0.1, by paired student t-test) and N (6.9 +/- 25%, P greater than 0.1). After placebo ingestion, the average changes from baseline in Vm and N also were not statistically significant (-1 +/- 18% and 14.9 +/- 30.3%, respectively). Furthermore, when compared with the changes measured after placebo intake, acetazolamide ingestion was associated with a nonsignificant 4.3 +/- 28.7% change in Vm (P greater than 0.1) and a -8 +/- 30.9% change in N (P greater than 0.1). With 20 subjects tested, the calculated average minimum change in leukocyte velocity that could have been detected with this technique (P less than 0.05, by paired student t-test) is about 9%.(ABSTRACT TRUNCATED AT 250 WORDS)