An Unusual Case of Concurrent Central Retinal Vein and Cilioretinal Artery Occlusion in a Healthy Patient

It is rare for young, healthy patients to have retinal venous or arterial occlusions and even rarer for both to occur in concert. Such an occurrence should prompt a rapid and extensive workup to prevent further complications. We present our patient, a 37-year-old Lebanese male, who reported a 3-day history of blurring of vision in his left eye. He had no medical or ocular history and is a nonsmoker. Examination of the left fundus revealed inferior macular edema and retinal whitening associated with tortuous retinal veins. He was diagnosed with a combined central retinal vein and cilioretinal artery occlusion. Emergency treatment was done for an acute arterial occlusion. Embolic and thrombotic causes were excluded with investigations. The only positive result was homozygosity for 677C>T mutation of the 5,10 methylenetetrahydrofolate reductase (MTHFR) enzyme gene. MTHFR enzyme breaks down homocysteine, which is atherogenic and prothrombotic. This mutation can lead to a prothrombotic state, precipitating this occurrence. In fact, the Lebanese population is known to have the highest incidence of such mutations, but there are surprisingly few reports on retinal vascular occlusions attributed to this. He was promptly treated with antiplatelet therapy, possibly preventing a full-blown central retinal vein occlusion. After 4 weeks, his vision improved to 6/6 bilaterally. Examination showed less tortuous veins, no more retinal whitening, resolution of macula edema and visual field defect. Hyperhomocysteinemia can be significant in patients without ischemic risk factors. It is vital to manage these patients promptly, preventing future sight and life-threatening events.