An evaluation of the darkroom prone provocative test in family members of primary angle closure glaucoma patients

Purpose: To compare ocular biometric parameters with darkroom prone provocative test (DRPPT) in family members of primary angle closure glaucoma (PACG) patients. Methods: One hundred and forty-nine family members of 46 PACG patients underwent ocular examination included slit lamp biomicroscopy, gonioscopy, fundus examination using +90 D lens, Goldmann applanation tonometry, darkroom prone provocative test, perimetry on Humphrey's field analyzer II and optic disc evaluation using HRT II. Ultrasonic ocular biometry and the DRPPT were then performed. IOP≥ 8 mmHg rise from baseline with iridocorneal touch was considered as a positive test. Results: Of the 149 family members examined, 55 (36.9%) were found to have PACG. Forty (72.7%) of these had subacute PACG and 15 (27.3%) were found to have chronic PACG. Thirty-nine (70.3%) of the affected members showed a positive DRPPT. Mean anterior chamber depth (ACD) was 2.03±0.3, 2.3±0.4, 2.7±0.3 mm (P = 0.0001) and mean lens thickness was 4.41±0.39, 3.99±0.5, 3.93±0.4 mm (P = 0.0001) in DRPPT positives, borderlines and negatives respectively. ROC curve (ACD) plotted showed cutoff value of 2.07 mm (sensitivity 88.57%) for screening. Conclusion: Anterior chamber is shallowest, lensis thickest and axial length is shortest in affected and DRPPT positive, family members of PACG patients.