To determine the efficacy of sustained topical therapy with dorzolamide hydrochloride, 2%, on visual acuity and cystic macular lesions in patients with retinitis pigmentosa and Usher syndrome.
In a retrospective case series at a university hospital, 64 eyes of 32 patients with retinitis pigmentosa or Usher syndrome receiving treatment with the topical dorzolamide formulation for 6 to 58 months were enrolled. Changes in visual acuity on the Early Treatment Diabetic Retinopathy Study chart and central foveal zone thickness on optical coherence tomography were measured during follow-up for the duration of treatment.
Among the study cohort, 20 of 32 patients (63%) showed a positive response to treatment in at least 1 eye and 13 patients (41%) showed a positive response in both eyes. Four patients (20%) showed an initial response and a subsequent rebound of macular cysts. In 8 patients (25%), there was no response to treatment and the macular cysts worsened when compared with the pretreatment level. Ten patients (31%) had improvement in visual acuity by 7 or more letters in at least 1 eye at the most recent follow-up visit. Sixteen patients (67%) showed a reduction of more than 11% in the central foveal zone thickness in at least 1 eye when compared with the pretreatment level.
Patients with either retinitis pigmentosa or Usher syndrome who received treatment of cystoid macular edema with topical dorzolamide followed by an optical coherence tomography–guided strategy showed a decrease in central foveal zone thickness in most cases. Visual acuity improved in almost one-third of the cases, suggesting a potential corresponding visual benefit.