Evaluation of pupillary block component in angle-closure glaucoma.

To evaluate the amount of the pupillary block component in primary angle-closure glaucoma, the dark-room prone-position test was carried out in 30 eyes of 20 primary angle-closure glaucoma patients, before and one month after argon laser iridotomy. The pupillary block component in the prone position (5.8 +/- 5.6 mmHg), which is the amount of reduction in IOP rise in the post-laser dark-room prone-position test, composed 67.8% of the IOP rise in the pre-laser dark-room prone-position test (8.6 +/- 5.6 mmHg). The amount of the pupillary block component correlated significantly with the IOP rise in the pre-laser dark-room prone-position test (r = 0.880, P < 0.001). The amount of the non-pupillary block component was relatively constant and correlated poorly with the IOP rise in the pre-laser dark-room prone-position test (r = 0.163, P = 0.386). The pupillary block component was significantly larger than the non-pupillary block component in the eyes with an IOP rise of > or = 7 mmHg in the pre-laser dark-room prone-position test (P < 0.01). The dark-room prone-position test could be useful in evaluating the pupillary block component in angle-closure glaucoma eyes and helpful in making a decision for laser iridotomy.