[Ultrasound biomicroscopic dark room provocative test]

To compare the clinical application of ultrasound biomicroscopic (UBM) dark room provocative test and traditional one in screening primary angle-closure glaucoma (PACG).

22 eyes (22 cases) with PACG in prodromal stage and 30 eyes (15 cases) with deep anterior chamber and wide angle of 15 normal persons were observed in this trial. Traditional dark room provocative test and UBM dark room provocative test were performed on all the 52 eyes at the same day time on separate days. With different positive diagnostic criteria, the sensitivity of the two methods was compared by using chi-square analysis.

After staying in dark room for 2 hours, in PACG group, the intraocular pressure (IOP) in 10 of 22 eyes raised more than 1.07 kPa (1 kPa = 7.5 mmHg), and in 12 eyes less than 1.07 kPa or had no changes; appositional angle closure was found by Goldmann gonioscopy in 8 eyes; 3 eyes in two quadrants, 5 eyes in more than two quadrants; the appositional angle closure was found by ultrasound biomicroscopy in 15 eyes; 3 eyes in one quadrant, 5 eyes in two quadrants, 7 eyes in more than two quadrants. In the control group, IOP raised more than 1.07 kPa in 3 eyes. There was no appositional angle closure found in the control group. With the appositional angle closure as a positive diagnostic criterion, the sensitivity of the traditional test and UBM dark room test was 31.8% and 68.2%, respectively. With statistic chi-square test, there is a statistically significant difference between the two methods (P < 0.05).

The sensitivity of UBM dark room provocative test is higher than that of the traditional one. The specificity of both methods is 100%. UBM dark room provocative test elevates the sensitivity and specificity of traditional dark room test, and reduces the false negative or positive rate in screening PACG, that is helpful to its accurate diagnosis.