TOPLINE: 

In a study involving about 12 million adults, those with a deficiency of vitamin D had a 28.6% higher risk of developing dry eye disease than those with adequate levels of the nutrient.

METHODOLOGY: 

• Researchers conducted a retrospective cohort study to evaluate whether adults with a deficiency of vitamin D were at an increased risk of developing dry eye disease.
• They used electronic health records of adults from a large US-based database, with records spanning from September 2005 through September 2025.
• After propensity score matching, the study included more than 6 million adults deficient in vitamin D and an equal number of those without the deficiency (mean ages, 50.3 and 50.8 years, respectively; 65.2% and 64.1% women, respectively).
• The primary outcome was a new diagnosis of dry eye disease.
• The median follow-up duration was 1261 days for adults with a deficiency of vitamin D and 1294 days for those with adequate levels of the nutrient.

TAKEAWAY: 

• During follow-up, 3.3% of adults with a deficiency of vitamin D developed dry eye disease compared with 2.7% of those without the deficiency.
• Adults with a deficiency of vitamin D had a 28.6% higher risk of developing dry eye disease compared with the other group (hazard ratio, 1.286; P < .001).
• Over time, adults deficient in vitamin D had a progressively higher cumulative incidence of dry eye disease than those not deficient in the nutrient: 0.83% vs 0.73% at 1 year, 3.58% vs 2.89% at 5 years, 7.22% vs 5.52% at 10 years, and 17.87% vs 14.16% at 20 years.

IN PRACTICE:

In patients with dry eye disease, “identifying and correcting low vitamin D levels may be a reasonable adjunct to standard…therapies, while recognizing that supplementation should be guided by general medical indications rather than used as a stand-alone treatment” for the condition, the researchers wrote. “Addressing micronutrient imbalances through targeted therapies and public health initiatives could be crucial for reducing the incidence and severity” of dry eye disease, “enhancing patient quality of life.”

SOURCE:

The study was led by Shon B. Shmushkevich, of the University of Miami Miller School of Medicine. It was published online on February 26, 2026, in the American Journal of Ophthalmology.

LIMITATIONS: 

The study used diagnosis codes instead of measurements of vitamin D levels or standardized dry eye tests. Key factors such as autoimmune disease, medications, screen time, vitamin D supplements, and social determinants were not reliably recorded. Owing to the retrospective design of the study, researchers could not establish that deficiency of vitamin D caused dry eye disease.

DISCLOSURES:

The research was funded in part by the National Institutes of Health Center Core Grant and the Research to Prevent Blindness Unrestricted Grant. The authors declared having no competing interests.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.