Purpose: To determine the efficacy of the dark-room prone provocative test (DRPT) for primary angle closure glaucoma. Method and subject: observation, comparative study, 64 eyes of 41 subjects aged 35 years, whose peripheral anterior chamber were or or=8 mmHg rise from baseline was considered as a positive test. Result: The mean IOP pre-test was 13.13 + or - 1.68 mmHg and post-test was 18.61 + or - 2.12 mmHg, showing a significant increase with p = 0,001. The DRPT results were positive in 22 eyes (34.4 percent)
42 eyes (65.6 percent) had negative results. There is no significant difference in gender and age between positive and negative groups. The positive rate in the fellow eye of subjects who had been diagnosed with glaucoma in one eye was significantly higher than those having no history of glaucoma, p=0.002. The mean IOP pre-test of the positive group was significantly higher than that of the negative one with p=0.028. The number of angle closure was also significantly higher in the positive group with p=0.000. The number of angle closure was significantly correlated with the amount of IOP elevation induced by DRPT (r=0.827). Conclusion: DRPT is an effective test in the detection for primary angle closure glaucoma.