Effect of vitamin D deficiency on spatial contrast sensitivity function

Background The association between plasma vitamin D deficiency and contrast sensitivity function was investigated. Methods Forty-one eyes of 41 subjects with vitamin D deficiency with plasma vitamin D level <20 ng/mL (Group 1), and 30 eyes of 30 subjects without vitamin D deficiency with plasma vitamin D level >= 20 ng/mL (Group 2), were included in this prospective study. OPTEC 6500 was used to measure the contrast sensitivity function at all spatial frequencies involving 1.5 cpd, 3 cpd, 6 cpd, 12cpd, and 18 cpd. The average and sectorial retinal nerve fibre layer thickness, the average and minimum ganglion cell-inner plexiform thickness and tear meniscus height were measured by using optical coherence tomography. Results A significant difference was present between Group 1 and Group 2 regarding the plasma vitamin D level (12.4 +/- 4.7 ng/mL in Group 1 versus 27.1 +/- 6.7 ng/mL in Group 2 p < 0.001). All spatial frequencies of contrast sensitivity function were significantly greater in Group 2 than those in Group 1, as follows: 45 +/- 22.6 in Group 1 versus 57.5 +/- 20.9 in Group 2, p = 0.08 in 1.5cpd; 71.3 +/- 31.3 in Group 1 versus 91.8 +/- 27.8 in Group 2, p = 0.001 in 3cpd; 77.9 +/- 39.9 in Group 1 versus 100.4 +/- 38.4 in Group 2, p = 0.013 in 6cpd; 32 +/- 17.5 in Group 1 versus 48.8 +/- 25.2 in Group 2, p = 0.002 in 12cpd; and 12.1 +/- 5 in Group 1 versus 17.5 +/- 9.5 in Group 2, p = 0.001 in 18cpd. However, there were no significant difference between two groups in terms of retinal fibre layer thicknesses, ganglion cell-inner plexiform layer thicknesses, and tear meniscus height. Conclusion Vitamin D deficiency can lead to a decrease in contrast sensitivity function that is an indicator of visual quality. This may be an underlying reason for certain visual complaints.