Purpose: To demonstrate the presence of a rebound effect with the use of acetazolamide for the treatment of cystoid macular edema (CME) in patients with retinitis pigmentosa (RP).
Methods: Six patients with RP and cystic-appearing lesions in the macula demonstrated by fluorescein angiography and/or optical coherence tomography (OCT) were treated with an oral form of carbonic anhydrase inhibitor (acetazolamide [500 mg]) as a single daily dose.
Results: All patients, treated with acetazolamide for a period of 3 weeks to 5 weeks, had initial improvement of macular edema demonstrated by OCT. However, extended use of acetazolamide, for at least 8 weeks to 12 weeks, resulted in recurrence (rebound) of CME in 3 of the 6 patients.
Conclusions: Results from our study suggest that rebound of CME with the continued use of acetazolamide observed by OCT may occur more frequently than previously appreciated.