Hyperhomocysteinemia and retinal vascular occlusive disease

Elevated plasma homocysteine is an independent risk factor for thrombosis and vascular disease. This prospective study compared plasma total homocysteine levels in patients with retinal vascular occlusive disease and in matched healthy controls.

We measured plasma total homocysteine in 56 consecutive patients with recently diagnosed retinal vascular occlusive disease: 36 had central retinal vein occlusion, 12 branch retinal vein occlusion, and 8 retinal artery occlusion, and compared them with 59 age- and sex-matched healthy controls. Homocysteine levels were determined by high-performance liquid chromatography with electrochemical detection. Hyperhomocysteinemia was defined as a plasma homocysteine level above the 95th percentile in the control group (13.6 micromol/L).

Mean plasma total homocysteine levels were significantly higher in patients than controls (16.1 +/- 8.3 vs. 8.96 +/- 5.6 micromol/L p < 0.001). Mean homocysteine levels were significantly higher in the retinal vein occlusion and retinal artery occlusion groups than the control group (15.3 +/- 8.2 and 20.95 +/- 6.9 vs 8.96 +/- 5.6 micromol/L, p < 0.001). Estimates of the relative risk indicated that the risk of hyperhomocysteinemia was significantly higher in patients with retinal vascular occlusive disease than controls. Hyperhomocysteinemia was present in 37 (66.1%) of the 56 patients with retinal vascular occlusive disease but only 2 (3.4%) controls (odds ratio [OR] 47.5, 95% confidence interval [CI] 9.8-149.9). Hyperhomocysteinemia was present in 29 (60.4%) of the patients with retinal vein occlusion (OR 43.5, 95% CI 8.77-141.93) and in 6 (75%) patients with retinal artery occlusion (OR 85.5, 95% CI 7.49-1,173.1).

High plasma homocysteine is a risk factor for retinal vascular occlusive disease so it may be useful to measure homocysteine in the management of these patients. A randomized, controlled trial is required to study the effect of lowering with homocysteine folic acid and other B vitamins on the risk of recurrent vascular occlusion in the same eye or its development in the fellow eye.