RETINAL NERVE-FIBER LAYER THICKNESS IN NORMAL HUMAN EYES

Purpose: To measure the histologic thickness of the retinal nerve fibe r layer (RNFL) in normal human eyes, Methods: Human eyes were obtained at autopsy within 6 hours postmortem. The retina was dissected into f our quadrants and serially sectioned in historesin. The RNFL thickness was measured histologically in all Four quadrants ai:the disc margin and at regular intervals from the disc margin. Measurements of the RNF L thickness also were obtained al the fovea and in the retinal periphe ry. Results: Ten eyes of ten white individuals were studied. Age (mean +/- standard deviation) was 53.1 +/- 19.6 years (range, 18-76 years). For the eyes studied, the disc area (mean +/- standard deviation) and cup:disc ratio (mean +/- standard deviation) were 1.92 +/- 0.1 mm(2) and 0.3 +/- 0.08, respectively. Mean superior, inferior, nasal, and te mporal RNFL thickness at the disc margin was 405, 376, 372, and 316 mu m, respectively. In all four quadrants, the RNFL thickness decreased with increasing distance from the disc margin. The average superior an d inferior RNFL thickness was inversely related to age (P = 0.033. P = 0.097, respectively). The average RNFL thickness was not related to d isc area. The average RNFL thickness just superior, inferior, nasal, a nd temporal to the foveola was 27, 34, 26, and 12 mu m, respectively. The average RNFL thickness just posterior to the ora serrata in the su perior, inferior, nasal, and temporal retinal periphery was 8 to 11 mu m. Conclusion: The peripapillary RNFL thickness in humans is thicker than that seen in nonhuman primates. The thinnest peripapillary RNFL i s in the region of the papillomacular bundle. These data can be used t o determine the accuracy of NFL analyzers in obtaining in vivo RNFL th ickness measurements.