In this issue of the Archives, Barkana et al1 report remarkable agreement between gonioscopy and ultrasound biomicroscopy (UBM) in detecting appositional angle closure and provide strong evidence that such examinations should be made under dark room conditions. In 18 subjects with the gonioscopic finding of appositional angle closure under dark room conditions, all but one (94%) were found to have iridotrabecular apposition under dark room conditions by UBM, whereas only 56% had a closed angle by UBM when the room lights were turned on. The authors thus validate the important teaching that one must not let either room light or the slitlamp beam constrict the pupil, as this may result in failure to diagnose angle closure. Barkana and colleagues’1 work also provides an estimate (38%) of how frequently light will open appositionally closed angles.
Palmberg P. Shedding Light on Gonioscopy. Arch Ophthalmol. 2007;125(10):1417-1418. doi:10.1001/archopht.125.10.1417