Early Loss of Central Visual Acuity in Glaucoma

Central visual acuity is usually maintained until late in the course of glaucoma. Ten patients (5 men, 5 women) between the ages of 25 and 79 were found to have decreased visual acuity associated with central or centrocaecal scotomas early in their course. Five patients had chronic open-angle glaucoma, three had pigmentary glaucoma, one had juvenile glaucoma, and one had Axenfeld's syndrome. A Marcus Gunn pupil was present in all six patients not on miotics. Most lost central acuity at pressures under 30 mmHg. Seven patients had vision of 20/200 or less. All with marked visual loss had a cup disc rate of .8 or greater. Other causes were carefully ruled out. Proposed mechanisms for the development of these central defects include either double Bjerrum scotomas which extend centrally or early papillomacular bundle involvement due to temporal cupping. This study demonstrates that decreased vision with associated central field loss can be a relatively early finding in glaucoma.