Therapeutic effect of prolonged treatment with topical dorzolamide for cystoid macular oedema in patients with retinitis pigmentosa

Aim: To evaluate the therapeutic effect of continuous treatment with topical dorzolamide (a carbonic anhydrase inhibitor) for cystoid macular oedema (CME) associated with retinitis pigmentosa (RP). Methods: 18 eyes in 10 patients with CME secondary to RP were included. Baseline visual acuity, visual field and optical coherence tomography (OCT) measurements were obtained for all patients. All patients used 1% dorzolamide three times daily in each affected eye. Patients underwent follow-up examinations at 1, 3, 6, 12 and 18 months after treatment. The response to treatment was monitored by the Humphrey field analyser (HFA: the central 10-2 program); in addition, foveal thickness was measured by OCT. Evaluation of 'macular sensitivity' was calculated by HFA as the average of 12 central points. Results: The 'macular sensitivity' in 10 eyes in which CME was almost completely resolved was significantly improved (p<0.05). In eight of the nine eyes in which CME was almost completely resolved within 6 months, the therapeutic efficacy persisted through 18 months. Five eyes which were almost completely resolved or showed an initial response within 6 months experienced recurrence of CME. Conclusions: The prolonged (longer than 1 year) use of topical dorzolamide is effective for the treatment of CME in patients with RP. Therefore, we propose topical dorzolamide treatment as a first choice.