Optic disc and retinal nerve fiber layer assessment

The progression of the optic disc and the presence of any RNFL defects were determined through an evaluation of an entire series of stereoscopic optic disc and red-free RNFL photographs. Serial stereoscopic photographs were displayed on a liquid crystal display monitor. Two glaucoma experts (KRS and JYL) independently assessed all photographs to estimate the glaucoma progression. The most recent photograph was compared to the baseline photograph for each patient. The experts were not aware of each other's assessments and were also blind to all clinical, OCT, and VF information. Both evaluators reviewed all photographs for each eye before making an assessment and were asked to determine the glaucomatous optic disc or RNFL progression, as revealed by an increase in the extent of neuroretinal rim thinning, enhancement of disc excavation, and/or any widening or deepening or new appearance of an RNFL defect. Each grader classified each glaucomatous eye as either stable or progressing. If the RNFL photographs were difficult to evaluate due to the presence of diffuse atrophy or an invisible RNFL resulting from a lightly pigmented fundus, the progression was determined by an optic disc assessment. If the opinions of the two graders differed, that eye was excluded from the subsequent analysis.