Retinal nerve fiber layer versus optic nerve head evaluation in the diagnosis of glaucoma and glaucoma suspect patients

PurposeTo evaluate the role of retinal nerve fiber layer (RNFL) versus optic disc parameters in the diagnosis of glaucoma and glaucoma suspect using spectral domain optical coherence tomography (SD-OCT).Patients and methodsForty-five normal, 51 glaucoma suspect, and 54 glaucomatous eyes were examined. Complete ophthalmic examination, white-on-white perimetry, and SD-OCT were performed for all patients. RNFL thickness of quadrants and clock hours and optic disc parameters were recorded. Area under receiver operating characteristic curves (AUC) were used to assess the performance of OCT.ResultsRNFL thickness and optic head parameters were used discriminate the three groups for all comparisons. Inferior, average, and superior RNFL thickness were the best parameters that discriminated normal from glaucoma (AUC: 0.96-0.99), suspect from glaucoma (AUC: 0.84-0.91), and normal from suspect (AUC: 0.71-85). Rim area and vertical cup/disc ratio were the best parameters that discriminated normal from glaucoma (0.87-0.90), suspect from glaucoma (AUC: 0.82-0.83), and normal from suspect (0.76).ConclusionThe ability of SD-OCT to differentiate between normal and glaucoma suspect eyes from glaucomatous eyes is better for RNFL thickness than optic nerve head parameters. The ability of both RNFL thickness and optic disc parameters is less in differentiating normal from glaucoma suspect eyes.