Ability of Different Scanning Protocols of Spectral Domain Optical Coherence Tomography to Diagnose Preperimetric Glaucoma

Abstract

To evaluate the ability of the optic nerve head (ONH), retinal nerve fiber layer (RNFL), and ganglion cell complex (GCC) parameters of spectral domain optical coherence tomograph (SDOCT) in detecting preperimetric glaucoma. In a cross-sectional study, 34 preperimetric glaucoma eyes (34 patients) and 72 control eyes (72 subjects) with large physiologic optic disc cupping underwent ONH, RNFL, and GCC imaging with SDOCT. Preperimetric glaucoma was diagnosed in the presence of glaucomatous optic neuropathy on masked evaluation of optic disc photographs by two glaucoma experts and normal visual fields. The ability of SDOCT parameters to discriminate preperimetric glaucoma eyes from eyes with large physiologic cups was evaluated by areas under the receiver operating characteristic curves (AUC), sensitivities at fixed specificities, and likelihood ratios (LR). All SDOCT parameters were significantly different (P < 0.05) between the two groups. The ONH, RNFL, and GCC parameters with best AUCs to differentiate preperimetric glaucoma from eyes with large physiologic cups were vertical cup to disc ratio (0.76), inferior quadrant RNFL thickness (0.76), and inferior quadrant GCC thickness (0.75), respectively. Sensitivities at 95% specificity of SDOCT parameters ranged between 15% and 29%. Likelihood ratios of outside normal limits category of parameters ranged between 3 and 11, and within normal limits category between 0.5 and 0.8. Diagnostic abilities of ONH, RNFL, and GCC parameters of SDOCT to differentiate preperimetric glaucoma eyes from control eyes with large physiologic cupping were only moderate.