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Une présentation rare d’une occlusion veineuse hémi-rétinienne associée à une occlusion artérielle hémi-rétinienne concomitante

The purpose of this case description is to illustrate a rare presentation of hemiretinal vein and hemiretinal artery occlusion occurring simultaneously in a patient, to discuss the pathophysiology and the possible underlying risk factors.

A 54-year-old male, with a history of diabetes and hypertension, presented with a sudden and painless vision loss in the right eye. The best corrected visual acuity was reduced to counting fingers in the right eye and was 10/10 in the left eye. Anterior segment was unremarkable in both eyes. Fundus examination of the right eye revealed blurred disc margins nasally, peripapillary cotton-wool spots, deep hemorrhages, venous tortuosity and sheathed arteries in the inferior part of the retina. Fundus examination of the left eye was normal.

Fluorescein angiography of the right eye showed delayed filling of the inferotemporal artery with delayed venous filling of the inferior veins and extensive areas of capillary non-perfusion in the inferior retina suggesting the presence of a hemiretinal vein occlusion associated to a branch retinal artery occlusion. Fluorescein angiography of the left eye showed signs of mild diabetic retinopathy. Swept-Source optical coherence tomography showed a cystoid macular edema in the right eye and was unremarkable in the left eye. The patient was administered three injections of Bevacizumab in his right eye and had photocoagulation of the inferior hemiretinal field. At 3-month follow-up, visual acuity was 8/10 in the right eye, fundus examination showed resolution of hemorrhages and sheathed inferotemporal and inferonasal arteries, establishing a retrospective diagnosis of hemiretinal artery occlusion concurrent to the hemiretinal vein occlusion.

The occurrence of branch retinal vein and branch retinal artery occlusion in the same eye may be explained either by a compression of the artery by the dilated vein which is called a reverse-crossing mechanism or by transmission of the back pressure from the dilated vein to the arterial circulation. This condition happens most frequently in patients with systemic comorbidities such as diabetes, hypertension, elevated lipids, or hyperhomocysteinemia.

Combined branch retinal artery and branch retinal vein occlusion is a rare condition that may occur either simultaneously or in a sequential way. A thorough systemic work-up for cardiovascular risk factors is mandatory.