Histologic RNFL Thickness in Glaucomatous Versus Normal Human Eyes.

PURPOSE

To compare the retinal nerve fiber layer (RNFL) thickness in histologic sections of glaucomatous eyes to nonglaucomatous eyes, to ascertain whether RNFL thinning can be confirmed histologically in human eyes.

MATERIALS AND METHODS

Seven postmortem glaucomatous eyes were compared with 17 normal postmortem eyes. The eyes were sectioned using the "umbrella technique" and measurements were performed on 4 concentric peripapillary rings with diameters of 3.0, 3.5, 4.0, and 4.5 mm. An overall average thickness, as well as an average for each of the temporal, superior, nasal, and inferior quadrants was obtained. The RNFL thickness of both groups in each of the quadrants in each of the rings were compared.

RESULTS

The overall average thickness (μm±SD) of the glaucomatous eyes for the 3.5-mm diameter rings was 36.5±10.6 compared with an average thickness of 60.3±19.5 in the nonglaucomatous eyes (P=0.006). The average sectorial thickness of the 3.5-mm diameter rings for the glaucomatous and normal eyes, respectively, was: temporal 30.9±10.6, 49.2±26.4 (P=0.080); superior 41.0±13.2, 75.3±26.5 (P=0.003); nasal 32.7±7.8, 48.1±15.0 (P=0.023); and inferior 41.6±14.4, 69.4±22.4 (P=0.012). The overall physiological "double hump" pattern was less preserved in the glaucomatous eyes.

CONCLUSIONS

In this study a statistically significant loss of RNFL tissue was demonstrated when comparing glaucomatous to normal postmortem human eyes. These findings strengthen data obtained using imaging techniques that quantify RNFL thickness.