Pressure-dependent neuroretinal rim loss in normal-pressure glaucoma.

Abstract

To evaluate whether, in normal-pressure glaucoma, the level of intraocular pressure is correlated with the degree of glaucomatous optic nerve damage. Color stereo optic disk photographs of 98 eyes with the focal type of normal-pressure glaucoma, 17 eyes with the highly myopic type of normal-pressure glaucoma, and 36 eyes with the age-related atrophic type of primary open-angle glaucoma were morphometrically evaluated. In all three study groups, neuroretinal rim area declined significantly (P < .05) with increasing maximal intraocular pressure values. In different forms of open-angle glaucoma with normal intraocular pressure, eyes with relatively high intraocular pressure have more pronounced optic nerve damage than do eyes with relatively low intraocular pressure. This suggests a barotraumatic aspect in the pathogenesis of optic nerve damage in the normal-pressure glaucomas. It implies that therapeutically, an intraocular pressure in the low-normal range may less likely be associated with glaucoma damage than an intraocular pressure in the upper-normal range would be.