Retinal nerve fiber layer normative classification by optical coherence tomography for prediction of future visual field loss

Abstract

Purpose: To evaluate the utility of baseline Stratus optical coherence tomography (OCT; Carl Zeiss Meditec, Dublin, CA) retinal nerve fiber layer (RNFL) normative classification in the prediction of future visual field (VF) loss.

Methods: Eighty-eight eyes with suspected glaucoma with abnormal RNFL classification by Stratus OCT were followed up for more than 4 years. VF conversion in three consecutive tests was assessed after baseline Stratus OCT and VF examination. Baseline intraocular pressure, VF global indices, OCT RNFL thickness, and number of abnormal OCT sectors were compared between VF converters (CG) and nonconverters (NCG). Positive and negative predictive values (PPV, NPV) of OCT sectors with abnormal classifications were calculated with respect to VF conversion. Hazard ratios (HRs) of various risk factors, including abnormal OCT classification, with respect to future VF conversion, were determined by use of the Cox proportional hazard model.

Results: Twenty-one (23.9%) eyes showed VF conversion during follow-up. Baseline OCT RNFL thickness was significantly lower and the number of abnormal OCT RNFL sectors significantly greater in CG than in NCG patients (P = 0.022 for both). The PPV and NPV of normative OCT RNFL classification was highest in the inferior quadrant (50%, 87.1%, respectively). Baseline VF mean deviation (MD) and the number of abnormal OCT RNFL sectors were both associated with future VF conversion (HR, 0.788 and 1.290, respectively).

Conclusions: In patients with suspected glaucoma, an abnormal RNFL classification in the inferior area of the optic disc or an elevated number of abnormal RNFL sectors, as determined by Stratus OCT, were both associated with future VF conversion.