The retinal nerve fiber layer in normal and glaucoma eyes

Glaucoma leads to changes of the retinal nerve fiber layer (RNFL). This study was performed to evaluate glaucomatous alterations of the RNFL and to correlate them with other parameters of glaucomatous optic nerve damage. The study included red-free wide-angle fundus photographs of the RNFL of 453 normal eyes and 609 eyes with glaucoma. We evaluated the visibility of the RNFL in different fundus regions and the occurrence of localized RNFL defects. In the glaucoma eyes, including those with "early" glaucomatous optic nerve damage, the visibility of RNFL was significantly lower than in the normal eyes. The degree of RNFL visibility correlated with other morphological and perimetric parameters. Localized RNFL defects were detected in 20% of the glaucoma eyes. Their frequency increased significantly (P < 0.01) from an "early" glaucoma stage to a subgroup with medium advanced glaucomatous damage and decreased again to a stage with marked glaucomatous changes. They were significantly more common in eyes with normal pressure glaucoma, followed by eyes with primary open-angle glaucoma and finally eyes with secondary open-angle glaucoma. They were significantly associated with optic disk hemorrhages and notches of the neuroretinal rim. The results indicate that the glaucomatous changes of the RNFL are correlated with the optic disk alterations. This holds true also for eyes with "early" glaucomatous damage. It suggests that during every routine ophthalmoscopy the RNFL should be examined. Localized RNFL defects indicate optic nerve damage with a specificity of more than 90%. The contrast between localized and diffuse RNFL loss, the varying frequency of localized RNFL defects in different types of glaucoma and the association between localized RNFL defects and optic disk hemorrhages are diagnostically and pathogenetically important.