Central retinal vein occlusion: an important cause of blindness in glaucoma in the Negro

ABSTRACT

This study was designed to determine the frequency of central retinal vein occlusion as a cause of blindness in glaucoma. Glaucoma patients attending the author's practice over a four month period were examined specifically for evidence of central retinal vein occlusion (CRVO) and their visual acuity recorded. Evidence of CRVO was taken as the following tortuous anastamotic vessels on the disc; scattered retinal haemorrhages; and telangiectatic retinal vessels or scattered cotton wool spots in the retina in the absence of other retinal disease, eg. diabetic retinopathy. Blindness was accepted as a best corrected visual acuity of 20/200 or worse. The cause of blindness was recorded. 74 blind eyes were recorded, with 44 (60 percent) blind from glaucoma, 22 (30 percent) blind from CRVO. All patients were predominantly Negro. Central retinal vein occlusion is a common cause of blindness in glaucoma patients who are black. This is an important and previously unrecognized fact. In this study approximately one-third of glaucoma patients were blind from CRVO and not glaucoma itself. Essential hypertension and glaucoma are associated factors in CRVO, and each of them has a high incidence in Negroes, and they may be acting synergistically to produce the high incidence of blindness due to CRVO found in this study. This also explains the increase severity of glaucoma in the Negro. Tissue under-perfusion in both diseases may be the underlying explanation.(AU)