New research published in the journal Cornea has raised the possibility that vitamin D plays a role in dry eye syndrome.
Dry eye syndrome is a prevalent condition characterized by the eye’s lack of ability to maintain a healthy coating of tears. While not a severe condition, it is a nuisance.
No studies to date have evaluated the effect of vitamin D levels on dry eye syndrome. However, one study did find that patients with Sjogren’s syndrome have lower vitamin D levels. Sjogren’s syndrome is an autoimmune disease characterized, in part, by dry eyes.
The researchers recruited 247 patients from the Miami Veterans Affairs eye clinic. They surveyed the patients about dry eyes [called the Dry Eye Questionnaire (DEQ5)]. The researchers also took blood samples for vitamin D levels.
The researchers wanted to know, do vitamin D levels correlate with dry eye syndrome? Here’s what they found:
- Vitamin D levels were not significantly associated with many dry eye syndrome parameters, including presence of disease or disease severity.
- However, vitamin D levels did correlate with dry eye syndrome symptoms. For every 10 ng/ml increase in vitamin D levels, there was a quantifiable drop in the scale ratings in the dry eye syndrome symptom questionnaire (the DEQ5).
The researchers reached mixed conclusions:
“Although we did find a positive effect of vitamin D levels on dry eye syndrome symptoms, the effect was small and likely not clinically meaningful.”
However they also stated:
“Higher vitamin D levels had a small but favorable effect on DES symptoms.”
Future research is underway looking at this issue and should elucidate these mixed results. For example, the VITAL trial that is administrating vitamin D to 10,000 people and placebo to another 10,000 people is examining the incidence of dry eye disease in these groups. You can find full details of that portion of the VITAL study here.