Modified Dark Room Provocative Test for Primary Angle Closure

Dejiao Li

Purpose: To examine the diagnostic value of a modified dark room provocative test in detecting primary closure of the anterior chamber angle.

Methods: The cross-sectional observational prospective clinical study included suspects of primary angle closure. Using anterior segment optical coherence tomography (AS-OCT), we measured the 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 conditions at baseline and after 1.5 hours of dark adaptation. The number of closed angle quadrants assessed on AS-OCT images and upon gonioscopy were recorded. The dark room test was positive, if intraocular pressure increased by ≥8 mmHg after 1.5 hours of dark adaptation.

Results: The study included 76 subjects (76 eyes). The dark room test was positive in 32 (42%) eyes. Among them, the number of eyes with an increased number of closed angle quadrants was significantly higher for the OCT examination performed at 3 minutes of dark adaptation than for gonioscopy carried out at 1.5 hours of dark adaption (29(91%) eyes versus 21(66%) eyes; P=0.01). Kappa statistics showed a moderate agreement between increased closed angle quadrants obtained both after 3 minutes of dark adaption (k=0.44; P<0.001; sensitivity: 90.6%; specificity: 56.8%) and after 1.5 hours of dark room test (k=0.45; P<0.001; sensitivity: 65.6%; specificity: 79.5%) compared with the final intraocular pressure elevation.

Conclusions: A modified dark room provocative test with an assessment of the anterior chamber angle by OCT at 3 minutes of dark adaptation as compared with a gonioscopic angle assessment after 1.5 hours of dark adaptation had a higher diagnostic precision in predicting primary angle closure.

Key Words: Dark room provocative test; Primary angle closure glaucoma; Primary angle closure; Anterior segment optical coherence tomography