Localised wedge shaped defects of the retinal nerve fibre layer in glaucoma

Abstract

Glaucoma can be associated with a diffuse or localised loss of the retinal nerve fibre layer (RNFL). This study evaluated the wedge shaped localised RNFL defects. Red free wide angle RNFL photographs of 421 patients with glaucoma and 193 normal subjects were examined. Localised RNFL defects were described for one eye of the normal group and for 20% of the patients with glaucoma. They were usually located in the inferior temporal and superior temporal fundus regions. Within the glaucoma group, localised RNFL defects occurred most often (p < 0.05) in normal pressure glaucoma, followed by primary open angle glaucoma, and finally secondary open angle glaucoma. They were positively associated with disc haemorrhages. The localised RNFL defects had a high specificity to indicate optic nerve damage. The nerve fibre layer defects occurring more likely in mild rather than advanced glaucoma, they were helpful in the diagnosis of early glaucoma. The association between localised RNFL defects and disc haemorrhages and the varying frequency of localised RNFL defects in different types of glaucoma may be important diagnostically and pathogenetically.