Cystoid macula edema (CME) is a complication in approximately 10-15 percent of people affected by retinitis pigmentosa (RP). CME can cause increased vision loss and retinal deterioration beyond what occurs as a result of RP.
In an eight-patient clinical study funded by the Foundation Fighting Blindness, Gerald Fishman, M.D., University of Illinois at Chicago, demonstrated that dorzolamide, a drug commonly used to treat glaucoma, is effective in reducing the swelling and cysts associated with CME. Most patients showed sustained improvement of CME with long-term use of the treatment.
Though ophthalmologists use other drugs to treat CME including steroids and nonsteroidal anti-infl ammatory agents, many of these treatments can’t be used long term,because of unsafe side effects. With some of these treatments, recurrence of CME is also common.
A drug similar to dorzolamide, acetazolamide, is sometimes used to treat CME, but Fishman believes that patients are less likely to experience a recurrence of CME when using dorzolamide.
Fishman reports that all patients in his study showed a signifi cant reduction in swelling in at least one eye after using dorzolamide three times a day for one to two months. Six patients showed improvement in swelling in both eyes. Seven patients experienced a small degree of subjective improvement in their visual acuity. Three patients showed visual acuity improvement of seven letters or more.
Patients in the study continued treatment with dorzolamide for a period of 7 to 15 months. During that time, six patients showed sustained improvement in CME in at least one eye. Two patients had recurrence of CME in both eyes.
Results of the study were published in the January 10, 2007 issue of the British Journal of Ophthalmology.
Fishman notes that more patients need to be studied to make a more defi nitive conclusion about the effectiveness of dorzolamide for the treatment of CME. He will expand his Foundation-funded study to further document the sustained benefi t of dorzolamide, and also determine if the drug is more benefi cial when administered at an earlier stage of disease.
In a different study, which was covered in the winter 2007 issue of InFocus, Fishman showed that dorzolamide was effective in improving the retinal health of people affected by X-linked retinoschisis.
DISCLAIMER: Physicians differ in their approach to incorporating research results into their clinical practice. You should always consult with and be guided by your Physician’s advice when considering treatment based on research results.