Vitamin D Levels in Patients With Central Retinal Vein Occlusion- a Prospective Controlled Study

Retinal vein occlusion (RVO) is a common vascular disease of the eye. Studies have shown that the risk of venous thrombosis is higher in winter so even concerning RVO. Studies have shown a possible link between sun exposure and venous thrombosis. Vitamin D levels have been shown to have a similar seasonal variation, with a peak occurring in the summer. The primary source of vitamin D is from sunlight when ultraviolet B (UVB) radiation penetrates the skin and converts 7-dehydrocholesterol to 25-hydroxycholecalciferol vitamin D3 (25-OHVitD) via previtamin D. In Stockholm situated at latitude 59˚ 20΄ North, it is not possible to synthesize vitamin D at sufficient levels in winter and the exposure time required to reach a standard dose is impractical from at least October through March. The aim of the study is to evaluate vitamin D levels in central retinal vein occlusion (CRVO) patients and compare them with the vitamin D levels in randomly selected control patients matched for age and month of disease onset. This is to evaluate whether vitamin D deficiency may be a risk factor in the onset of CRVO. The hypothesis of the study is that patients with CRVO have lower levels of vitamin d than matched controls.