Differential diagnosis of central retinal vein obstruction.

When obstruction of the central retinal vein presents in its florid hemorrhagic form, with disc edema and myriad, widespread retinal hemorrhages, there can be little doubt as to the proper diagnosis. However, when obstruction is incomplete, there may be confusion as to terminology, etiology, and proper treatment. "Venous-stasis retinopathy" was the term used in the early 1960s to describe the ophthalmoscopic changes recognized as resulting from the chronic ischemic changes induced by severe occlusive disease of the carotid artery. In the late 1970s, others began to use the term "venous-stasis retinopathy" to describe the incomplete or nonflorid type of central vein obstruction. These two conditions, although similar in appearance, have differences that allow their differentiation. The main differentiating feature is that the retinal artery pressure, as measured by ophthalmodynamometry or oculopneumoplethysmography, is always low in the retinopathy of carotid occlusive disease. These two conditions must be differentiated in order to manage the retinopathy properly as well as to recognize the potential for neurologic catastrophe.