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K. Kashiwagi, T. Tsumura, R. Lavanya, P. J. Foster, T. Aung; Development of Iris Surface Profiling Program to Improve Detection of Eyes at Risk of Angle Closure Glaucoma. Invest. Ophthalmol. Vis. Sci. 2008;49(13):5096.
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© ARVO (1962-2015); The Authors (2016-present)
We developed a program bundled to the scanning peripheral anterior chamber depth analyzer (SPAC) for evaluating iris surface profile quantitatively. In this study, we present a principle of this program and compared differences in parameters regarding iris surface profile between eyes with angle closure and those without angle closure among eyes judged risky eyes with angle closure by SPAC evaluation.
This program mathematically determined a circle most likely representing iris surface contour using SPAC data. The program provided two-dimensional coordinate data (X, Y) and diameter (R) of the circle. Subjects over the age of 50 years who did not have any ophthalmic complaint were enrolled in this study. Routine ophthalmic examination including gonioscopic examination and SPAC measurement were performed. Among all participants, eyes with angle closure and those with judgments of P or S by SPAC evaluation indicating possibility of angle closure glaucoma were subject to the investigation. We compared parameters X, Y, and R between eyes with angle closure and those without angle closure.
Out of enrolled 1047 eyes from 542 subjects, 414 eyes satisfied the inclusion criteria for the current investigation. There were 226 eyes with angle closure and SPAC judged 200 eyes at a risk of angle closure out of these 226 eyes. We compared X, Y and R parameters between 226 eyes with angle closure and 188 eyes without angle closure. Paramaters of X, Y, and R of eyes with angle closure were 3.5±2.7, 5.1±6.4, and 2.0±7.0, respectively, while those of eyes without angle closure were -1.3±27.0, 14.3±44.7, and 12.2±52.2, respectively. All three parameters were significantly different between two groups. A center of mathematically determined circle of eyes with angle closure located much closer to the optic axis and the posterior pole, and a radius of these eyes was smaller compared with eyes without angle closure.
Iris surface profile between eyes with angle closure and those without angle closure among risky eyes judged by SPAC was significantly different. This supplemental program may improve to identify eyes with angle closure.
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