The severity of visual field defect and the defective angles of localized retinal nerve fiber layer using a novel approach

A modified novel analytical method for evaluating photographic retinal nerve fiber layer defect (RNFLD) was developed for the purpose of estimating the severity of early glaucomatous eyes. This new method was then compared with the original method, as described below, in relation to the visual field defect severity. The clinical records of 47 glaucomatous eyes with qualified photographs were obtained from a prior retrospective study. The reference point of the angle was set at the center of the optic disc center (COD group) and the central vessel trunk (COV group). Angle α was the angular width between the fovea and the proximity of RNFLD, while angle β (+c) was the sum of the angular width(s) of localized RNFLD. The correlation between the visual field parameters and the angles of RNFLD in the above two groups were analyzed. There were significant differences in angle α (p = 0.001) and angle β (+c) (p = 0.016) between the two groups. Angle β (+c) showed significant correlation with MD (p = 0.012), PSD (p = 0.035), VFI (p = 0.042) and MD (p = 0.016), PSD (p = 0.035), VFI (p = 0.031) in the COD and COV group, respectively. No correlation was found between angle α and the presence of central scotoma in both groups. Our novel method was more convenient in a clinical setting and noninferior to the original method.