Is acetazolamide effective in the treatment of diabetic macular edema? A pilot study

To investigate whether acetazolamide, already found to be helpful in decreasing cystoid macular edema in patients with retinitis pigmentosa, was also effective in the treatment of diabetic macular edema in nonproliferative retinopathy.

Two randomized age- and sex-matched groups (cases and controls) of 12 diabetics (five Type 1 and seven Type 2) were selected for this pilot study and graded for retinopathy (Early Treatment of Diabetic Retinopathy Study-Airlie House Classification). Cases were treated with acetazolamide for three months according to a standard protocol. The Early Treatment of Diabetic Retinopathy Study chart was used for assessing far-best corrected visual-acuity, and fluorescein angiography was performed using the Heidelberg Retina Angiograph. The Amsler grid-test and computerized-perimetry (Octopus 2000R) were also performed.

Fluorescein-angiographic findings and perimetric data improved significantly (p < 0.01) in the acetazolamide-treated cases compared to the controls while visual-acuity varied only slightly (p > 0.01). The Amsler grid-test resulted insignificant in our study (p > 0.05). No adverse effects or significant variations in laboratory tests were recorded.

Further clinical investigations involving larger numbers of patients and a longer follow-up are required to confirm these preliminary results. However, the present study seems to suggest that acetazolamide could be effective in reducing fluorescein-angiographic findings and improving perimetric data in diabetics with macular edema, even though the mechanism of action remains obscure. Visual-acuity varied only slightly.