Quantitative evaluation of iris convexity in primary angle closure.

Authors :: Nonaka A
Iwawaki T
Kikuchi M
Fujihara M
Nishida A
Kurimoto Y
Source :: American journal of ophthalmology [Am J Ophthalmol] 2007 Apr; Vol. 143 (4), pp. 695-7. Date of Electronic Publication: 2006 Dec 19.
Publication Year :: 2007
Abstract: Purpose: In eyes with primary angle closure (PAC), we quantitatively evaluated anterior bowing of the iris by means of ultrasound biomicroscopy (UBM).<br />Design: Retrospective, observational, and consecutive case series.<br />Methods: A total of 203 phakic eyes with PAC that had not undergone any surgical or laser treatment were included. Using UBM, we measured anterior chamber depth (ACD) and iris convexity (IC): the maximum distance from the posterior surface of the iris to the iris plane passing through the pupillary margin of the iris and iris root.<br />Results: The average IC was 0.22 +/- 0.1 mm, although there was considerable individual variation. The IC value was correlated weakly, albeit significantly, with age (r = 0.22, P < .01), and strongly with ACD (r = -0.57, P < .0001).<br />Conclusions: In eyes with PAC, older age and a more shallow ACD appear to be important causes of increased forward bowing of the iris resulting from pupillary block.