To the Editor.
—I read with great interest the article "Risk Factors of Branch Retinal Vein Occlusion" by Drs Johnston et al,1 published in the December 1985 issue of the Archives. I quote the following from their article: "Recently, however, HRVO [hemispheric retinal vein occlusion] has been suggested to be a different disease (hemicentral retinal vein occlusion) more closely resembling CRVO [central retinal vein occlusion] than BRVO [branch retinal vein occlusion]." This is not a correct statement. Hemicentral retinal vein occlusion is not an alternative name for hemispheric vein occlusion. Hemispheric vein occlusion is a branch retinal vein occlusion affecting one half of the retina, and the site of the pathologic condition is always at an arteriovenous crossing, which may be on the optic disc or very near to the optic disc. However, hemicentral retinal vein occlusion is seen in patients with a congenital abnormality, that is, a dual
Chopdar A. Hemispheric Retinal Vein Occlusion or Hemicentral Retinal Vein Occlusion. Arch Ophthalmol. 1986;104(8):1128. doi:10.1001/archopht.1986.01050200034028