Myopia (nearsightedness) is becoming more common around the world, especially among children. Many parents ask whether vitamin D might help protect their child’s vision. A recent review looked closely at whether vitamin D levels are directly linked to myopia risk — and what that may mean for families.

What Does the Research Say?

The review examined multiple cross-sectional studies, cohort studies, genetic research, and proposed biological mechanisms related to vitamin D and eye growth.

Several pediatric studies found that lower blood levels of vitamin D (measured as 25(OH)D) were associated with more myopic refraction or longer axial length, both of which relate to the development of myopia.

However, in many adult studies, the association between vitamin D and myopia was inconsistent. In addition, genetic studies that focused on vitamin D pathway genes did not confirm a clear cause-and-effect relationship.

Some biological pathways have been proposed — such as vitamin D’s influence on calcium regulation in eye muscles or the role of vitamin D receptors in the retina — but these ideas remain theoretical and unproven.

Vitamin D as a Marker of Outdoor Time

While there are interesting links between vitamin D and myopia in children, the current evidence does not show that vitamin D directly causes or prevents myopia. Instead, researchers believe vitamin D may simply serve as a marker for time spent outdoors.

Outdoor time is strongly associated with a reduced risk of developing myopia. One theory is that exposure to bright natural light helps regulate healthy eye growth, preventing the eye from elongating too much. Because vitamin D levels rise with sunlight exposure, lower levels may reflect less time outdoors rather than a deficiency that directly affects myopia.

What This Means for Our Patients

At this time, experts do not recommend vitamin D supplementation or vitamin D level testing specifically for myopia prevention or management. Instead, families should focus on proven strategies that support healthy visual development:

Encourage children to spend time outdoors daily in natural light.
Balance screen time and near work with regular breaks and outdoor play.
Schedule routine eye exams to monitor vision and eye growth, especially during childhood.

If you have concerns about your child’s risk of myopia or would like personalized guidance, our office is here to help.

Bottom Line

Vitamin D levels show some associations with myopia in children, but current research does not support vitamin D as an independent protective factor. Increasing outdoor time remains the most reliable, evidence-based approach to reducing the risk of myopia onset.

Sources

Myopia Profile: “Vitamin D, myopia, outdoor time and possible mechanisms: systematic review summary.” 
Optometry Times: “Time outdoors and myopia: making the case for vitamin D.”