Modified dark room test with OCT proves effective in detecting primary angle closure

A modified dark room provocative test using anterior segment optical coherence tomography was found effective in identifying primary angle closure, a study found.

“It was reported that AS-OCT as compared with gonioscopy was more sensitive to detect a temporary closure of the anterior chamber angle in some patients with a narrow anterior chamber angle,” the study authors said. “Consequently, AS-OCT was applied to image the anterior chamber angle in the dark room test.”

Investigators compared the diagnostic value of the dark room test after a dark adaptation period of 3 minutes with OCT as opposed to the conventional dark room test with an adaptation period of 1.5 hours with gonioscopy.

The prospective analysis included 76 eyes of 76 subjects with a mean age of 67.5 years. The Visante AS-OCT system (Carl Zeiss Meditec) was used to measure anterior chamber angle configuration at room light and after 3 minutes of dark adaptation. Gonioscopy and Perkin’s applanation tonometry were performed in room light at baseline and after 1.5 hours of dark adaptation.

Study results showed 32 eyes (42%) with positive dark room provocative tests. Of those 32 eyes with a rise in IOP of 8 mm Hg or more after 1.5 hours, OCT examination undertaken 3 minutes after dark adaptation identified angle closure in 29 eyes and gonioscopy performed at 1.5 hours of dark adaptation identified closure in 21 eyes; the difference was statistically significant (P = .013), the authors said.