Plasma total homocysteine and retinal vascular disease

Hyperhomocysteinaemia has been linked to macrovascular disease. Our aim was to investigate whether there is a relationship between fasting plasma total homocysteine levels and retinal vascular disease.

We measured the homocysteine levels in 70 patients with arterial or venous retinal vessel occlusion and compared them with the levels in 85 controls without evidence of ischaemic heart disease. Homocysteine levels were determined by high-performance liquid chromatography with electrochemical detection and compared after logarithmic transformation.

Homocysteine levels were found by univariate analysis (unpaired two-tailed t-test) to be significantly higher in the group with retinal artery occlusion than the group with retinal vein occlusion (p = 0.045) and in both groups compared with controls (18.4 and 13.8 vs 9.5 mumol/l; p = 0.0002 and < 0.0001, respectively). The controls, however, were significantly younger than the subjects (51.5 +/- 15.4 vs 66.2 +/- 11.9 years; p < 0.0001), but analysis of the results by age revealed significant differences between the groups and controls for the seventh decade (vein occlusions, p = 0.05) and for the eighth decade (artery occlusions, p = 0.037). Subgroup analysis of the retinal vessel occlusion group revealed significant differences in mean blood pressure between those with branch retinal vein occlusions (175/100 mmHg) and both those with central retinal vein occlusions (155/88 mmHg) and those with retinal artery occlusions (157/86 mmHg). Both vein occlusion subgroups also differed significantly with regard to homocysteine levels, branch < central (12.2 +/- 1.3 vs 15.0 +/- 1.6 mumol/l, p = 0.03). Multiple linear regression analysis revealed significant relationships between homocysteine levels and the presence of retinal vessel occlusion (p = 0.0002), serum creatinine (p = 0.001) and age (p = 0.003), but not gender.

We conclude that homocysteine may be a risk factor for retinal vascular disease and could be simply and cheaply treated with folate and vitamins B6 and B12.