Optic disc imaging in perimetrically normal eyes of glaucoma patients with unilateral field loss

To compare the ability of optic disc and retinal nerve fiber layer (RNFL) imaging to discriminate perimetrically unaffected eyes of glaucoma patients from normal eyes.

Forty-six primary open-angle glaucoma patients with glaucomatous visual field loss with achromatic perimetry in one eye and a normal visual field in the fellow eye and 46 normal controls were selected. Receiver operator characteristic (ROC) curves and sensitivities at fixed specificities were used to compare the performance of StratusOCT (Fast RNFL algorithm), GDx-VCC, HRT II, and clinical evaluation of optic disc photographs to distinguish perimetrically unaffected eyes of glaucoma patients from normal eyes.

The parameters with the largest area under the ROC curves (AUC) were as follows: inferior average RNFL thickness (0.92 +/- 0.03) for StratusOCT; linear cup-to-disc ratio (0.82 +/- 0.05) for HRT II; and nerve fiber layer index (0.69 +/- 0.06) for GDx-VCC. Clinical evaluation of stereoscopic disc photographs resulted in AUCs ranging between 0.80 and 0.85. The P values for pairwise comparisons of the AUCs of OCT's best parameter with those of HRT, GDx, and disc photographs were .06, < .001, and .17, respectively. The sensitivities at 95% specificity for the best parameters from StratusOCT (inferior average), HRT II (cup volume), GDx-VCC (temporal-superior-nasal-inferior-temporal average), and clinical evaluation of disc photographs were 61%, 39%, 37%, and 28%, respectively. OCT identified more perimetrically normal glaucomatous eyes as having abnormalities, compared to normals, than did HRT (P = .001), GDx (P = .001), or clinical evaluation of disc photographs (P < .001).

Optical coherence tomography (StratusOCT) may detect evidence of glaucomatous damage earlier than other imaging techniques and clinical evaluation of optic disc photographs in perimetrically unaffected eyes of primary open-angle glaucoma patients.