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B. Mani, F.T. S. Oen, Y. Huak Chan, S. Tien Hoh, C. Lin Ho, K. Kashiwagi, P.J. Foster, T. Aung; Use of Scanning Peripheral Anterior Chamber Depth Analyzer (SPAC) for Anterior Chamber Depth Assessment in Normal and Angle–Closure Subjects . Invest. Ophthalmol. Vis. Sci. 2006;47(13):5478.
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© ARVO (1962-2015); The Authors (2016-present)
To compare Scanning Peripheral Anterior Chamber Analyzer (SPAC) with conventional methods for central and peripheral anterior chamber depth grading in normal and angle–closure subjects.
SPAC is a new non–contact instrument, which uses optical principles to grade the peripheral and central anterior chamber depth (CACD). Study subjects were recruited from glaucoma and general ophthalmology clinics of the Singapore National Eye Centre. Included in the study were phakic subjects with primary angle closure, with or without glaucomatous optic neuropathy, as well as normal subjects with open angles. Those who had other ocular diseases such as corneal disorders, uveitis, pseudophakia and aphakia were excluded. The peripheral anterior chamber depth (PACD) was assessed using the modified van Herick (vH) grading system and CACD was measured with the IOL Master. One eye was randomly selected for analysis. Associations between PACD, CACD and SPAC measurements were assessed using Spearman’s correlation coefficient. ROC analysis (area under curve; AUC) was used to examine the performance of tests to identify angle–closure.
120 eyes of 120 subjects with angle–closure and normal eyes (62 with primary angle closure and 58 with open angles) were examined. Central anterior chamber depth by IOL Master was significantly correlated with SPAC–CACD (r=0.798; p<0.001). SPAC showed moderate correlation with peripheral anterior chamber depth grades by vH method (r=0.527; p<0.001). CACD measured by either SPAC or IOL Master correlated strongly with PACD grading by vH and SPAC (r=0.601 – 0.787;p<0.001). A vH grade of 25% or less, SPAC grades (S and P) and CACD of 2.1 mm or less gave the best performance for detection of angle–closures (AUC: 0.872, 0.790, 0.781 respectively). SPAC grades in combination with CACD 2 mm or less gave the AUC of 0.821.
The central and peripheral anterior chamber depth measurement by conventional methods and SPAC correlate well.
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