Circumferential profiles of peripapillary surface height with confocal scanning laser ophthalmoscopy

The purpose of this study was to compare the circumferential profiles of relative peripapillary retinal surface height (RPSH) between normal and glaucoma, with a confocal scanning laser ophthalmology (CSLO), and to examine the ability of the mean height to distinguish glaucoma from normal. Fifty-three patients with open-angle glaucoma and forty-three normal subjects matched for age, race and refractive error were studied. To extract circumferential profiles, we developed software to quantify RPSH from images obtained with a CSLO (Heidelberg Retina Tomograph (HRT), Heidelberg Engineering, Germany, Software: IR1-V1.11) outside the optic disc margin every 50 microns. Mean heights from circumferential profiles were calculated and compared between normal and glaucoma. Receiver operating characteristic (ROC) curves were used to evaluate sensitivity and specificity of the mean height to discriminate normal from glaucoma subjects. T he average (+/- SD) visual field mean deviation in the glaucoma group was -4.8 +/- 3.4dB. The average height of each circumference increased from the disc margin to 250 microns away in both normal and glaucoma subjects. There were statistically significant differences for the mean height (P < 0.001) between the two groups. The largest difference between normal and glaucoma was found in the inferior sector compared with the other sectors (p < 0.001). The sensitivity, specificity and diagnostic precision of the mean height were 83%, 67% and 76%, respectively. The mean height from the circumferential profiles of RPSH can be used as a useful marker to identify early glaucoma.