Optical coherence tomography (OCT) has been used clinically for the detection of glaucoma for over a decade; however, its clinical usefulness has not been particularly well documented. Although many studies have shown that OCT measurements can discriminate between healthy and glaucomatous eyes, the great majority of studies demonstrating this have had limited clinical value. This is because most analyses were based on measurements of retinal nerve fibre layer (RNFL) thickness provided as continuous variables, and a great deal of overlap between measurements in healthy and glaucomatous eyes was observed. This made it difficult to determine what values should be used clinically as limits for classifying eyes as diseased, and in most published studies, no limits were recommended. Nonetheless, the performance of OCT for detecting RNFL thinning in glaucoma has been impressive given its limited number of data points (current maximum 512 A-scans) and relatively unsophisticated analyses (primarily measurements of global and local RNFL thickness).

Recently, a normative database has been added to the latest version of OCT (StratusOCT, Carl Zeiss Meditec, Dublin, California, USA), allowing comparisons of measurements of RNFL thickness with measurements from 328 healthy eyes, thus providing …