Modified PDT may enhance outcomes in chronic chorioretinopathy

SINGAPORE — A modified version of photodynamic therapy enhances the treatment’s safety and efficacy for patients with acute or chronic chorioretinopathy, according to one surgeon speaking here.

Wai Mun Chan, MD, said conventional forms of the treatment have been shown to cause visual disturbances in up to 18% of patients treated and severe vision loss in 1% to 4% of patients. Photoreceptor function is also depressed shortly after photodynamic therapy (PDT) applications, he said.

“There is more risk than benefit with the conventional treatment,” he told attendees here at the Asia-Pacific Academy of Ophthalmology meeting. Altering the dosage amount and time may help improve the safety profile, he said.

In one study of 55 eyes, Dr. Chan and colleagues modified the PDT with verteporfin, and the eyes showed a mean gain of 1.67 lines and a 76% absorption rate. Severe decreases in vision were also eliminated, Dr. Chan said.

Another study was conducted on patients with acute chorioretinopathy to determine if similar results could be achieved. Of the 39 patients involved in that study, 18 were treated with PDT with verteporfin, while the remaining 21 were on placebo. Dr. Chan reported the results were similar for this group as for the chronic group.