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W.P. Nolan, J. See, T. Aung, Z. Ce, S. Radhakrishnan, D.S. Friedman, S.D. Smith, P.T. Chew; Detection of Patients at Risk of Angle–closure Using Anterior Segment OCT . Invest. Ophthalmol. Vis. Sci. 2005;46(13):145.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To compare a new non–contact imaging method, the anterior segment optical coherence tomograph (AS–OCT), with gonioscopy in the detection of occludable angles. Methods: Patients attending the glaucoma service at the National University Hospital in Singapore were recruited to this preliminary study evaluating a new prototype of the AS–OCT (Carl Zeiss Meditec, Inc, Dublin, CA, USA). All subjects underwent gonioscopy using the Goldmann 2–mirror lens under dim light conditions by a single observer. The angle width was graded according to the Scheie grading system for all four quadrants of the angle in both eyes. A quadrant of the angle was defined as occludable on gonioscopy if trabecular meshwork was not visible without indentation. All subjects underwent imaging in the sitting position with the AS–OCT under dark and light conditions by a separate single observer. An image of the nasal, temporal and inferior quadrants was recorded for each eye, and the quadrant was defined as closed if peripheral iris was apposed to the trabecular meshwork anterior to the scleral spur, and defined as narrow if a small slit was visible between the peripheral iris and the trabecular meshwork/angle anterior to the scleral spur. Results:Preliminary data have been obtained from 54 eyes of 29 patients. In 28 eyes the temporal quadrant of the angle was defined as occludable by gonioscopy. AS–OCT images demonstrated narrow or closed angles in 24 of these eyes (85.7%). In 46 eyes the inferior angle was defined as occludable by gonioscopy of which the AS–OCT imaging identified 40 (87%) as narrow or closed. Of 19 eyes in which the nasal quadrant was defined as occludable the AS–OCT correctly identified 17(89.5%). In total the AS–OCT correctly identified 81/93 (87.1%) occludable angle quadrants as narrow or closed. Conclusions: This new prototype of the AS–OCT has the advantage of providing a rapid non–contact method of imaging the drainage angle. These preliminary data demonstrate that the device performs well in identifying patients with angle–closure when compared with gonioscopy.
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