The effect of vitamin D deficiency on the retinal microvasculature: an observational case-control study.

purposeTo determine the effects of vitamin D deficiency on retinal microvascularity using optical coherence tomography angiography.

methodsThis study was designed as an observational case-control study. Ninety-eight eyes of patients with vitamin D deficiency and 96 eyes of healthy participants with serum vitamin D level >30 ng/mL were studied. Macula centered, 6.00 × 6.00 mm scan size images were taken. The vessel densities in the superficial and deep retinal capillary plexus, foveal avascular zone area, and choriocapillaris flow area were measured.

resultsThe groups were comparable in terms of best-corrected visual acuity, sex, axial length, refractive error, age, and adjusted intraocular pressure. The average vitamin D level was significantly lower in the study group (p=0.021). The whole, parafoveal, and perifoveal vessel densities in the deep capillary plexus were considerably higher in the study group than in the control group (p=0.012, p=0.014, and p=0.023, respectively). The foveal avascular zone area and the choriocapillaris flow area were similar in both groups (p=0.37 and p=0.27, respectively) there was a strong negative correlation between the serum vitamin D level and vessel density in the whole image, parafoveal, and perifoveal regions of the deep capillary plexus in the study group (Spearman's rho=-0.71, p=0.043; Spearman's rho= -0.79, p=0.011; and Spearman's rho = -0.74, p=0.032; respectively).

conclusionAn increase in vessel density might originate from vascular structural changes caused by vitamin D deficiency. The increased vessel density, especially in the deep capillary plexus, can enable early diagnosis of vitamin D-associated vasculopathy.