Efficacy and Prognostic Factors of Response to Carbonic Anhydrase Inhibitors in Management of Cystoid Macular Edema in Retinitis Pigmentosa

PURPOSE. To determine the efficacy and prognostic factors associated with carbonic anhydrase inhibitors (CAI) in the treatment of cystoid macular edema (CME) in retinitis pigmentosa (RP). METHODS. This was a cohort study of 81 subjects who were assessed before and after treatment. Spectral-domain optical coherence tomography (SD-OCT) was used to quantify CME. A reduction of at least 11% in central subfield (CSF) thickness was defined as objective evidence of response. RESULTS. In the 125 eyes that received topical dorzolamide, 40.0% demonstrated a response to treatment with a mean reduction in OCT CSF thickness of 105 lm (95% confidence interval [CI]: 82, 128). Mean starting visual acuity (VA) increased from 6/15 to 6/12 after a median time on treatment of 3.0 months. In patients prescribed oral acetazolamide, 28.1% of eyes (41.2% of patients) showed improvement in mean OCT CSF thickness of 115 lm (95% CI: 52, 177) over a median treatment interval of 4.0 months. Visual acuity improved from 6/15 to 6/12. Eyes that responded to topical dorzolamide were more likely to have autosomal recessive than autosomal dominant RP (44.6% vs. 23.3%, P = 0.02), and a higher mean baseline OCT CSF than eyes that did not respond (P = 0.02). CONCLUSIONS. We report that 40.0% of eyes (53.1% of patients) showed an objective improvement in CME after treatment with topical dorzolamide and 28.1% of eyes (41.2% of patients) after treatment with oral acetazolamide. Autosomal recessive RP and greater initial central retinal thickness predicted response to treatment with topical dorzolamide.