Continued Use of Dorzolamide for the Treatment of Cystoid Macular Edema in Patients with Retinitis Pigmentosa

Abstract

Aims: To determine the value of a topical carbonic anhydrase inhibitor for extended treatment of cystoid macular edema (CME) in patients with retinitis pigmentosa (RP).

Methods: Eight patients with RP and foveal cystic-appearing lesions observed on fundus examination and by optical coherence tomography (OCT) testing were treated with a topical form of carbonic anhydrase inhibitor.

Results: Foveal cystic-like spaces were documented by OCT testing in all eight patients prior to treatment. All patients showed a significant reduction in their foveal thickness (FT) and foveal zone thickness (FZT) in at least one eye after using 2% dorzolamide three times a day for 1 or 2 months. Six patients demonstrated an improvement in both eyes. After an additional 6 to 13 months of the same treatment regimen, of six patients who showed a sustained reduction in FT and FZT in at least one eye, four demonstrated this reduction in both eyes. While they still remained on Trusopt, a recurrence (rebound) of CME in both eyes was observed in two patients while one patient showed a sustained improvement in one eye and rebound of CME in the other eye. Out of 8 patients, 3 showed an improvement of their visual acuity by 7 letters or more, in at least one eye, on Snellen acuity charts which was determined as clinically significant.

Conclusion: Results from our study suggest that RP patients could potentially sustain a beneficial effect from continued treatment with a topical form of carbonic anhydrase inhibitor.