BY DIANA ALLEN, MS, CNS

Among the myriad physical changes and health problems associated with advancing age, dry, irritated eyes are common.

This problem is more prevalent among women and people over fifty, but younger adults and men are also affected.

The National Eye Institute suggests nearly 16.4 million Americans suffer from dry eye symptoms, including uncomfortable scratchiness, stinging and burning, redness, blurred vision, and increased sensitivity to light.

Normally, the autonomic action of blinking serves to maintain eye moisture by distributing a thin film of lubricating tears over the ocular surface. But in dry eyes, this tear volume or quality is insufficient.

Healthy tears are comprised of three layers: an aqueous layer that hydrates and cleanses, a lipid layer that inhibits evaporation, and a mucin layer that helps to spread tears evenly across the cornea.

Decreased ocular lubrication may be due to impaired synthesis of any of the three tear layers, or to other internal or environmental factors—for example, wind exposure, hormonal changes, excessive digital screen usage, or nutrient deficiencies.

Dry Eyes: A Closer Look at Vitamin A and Tear Quality

It is well known that vitamin A is critical to eye health and visual function. A 2019 study compared the effects of short-term vitamin A supplementation on the quantity and quality of tears in two groups of thirty young adult men—one group with dry eye complaints, the other without.

The men in each group were given a daily vitamin A dose of 5,000 IU for three consecutive days. Subjects underwent a series of diagnostic tests at baseline, during treatment, and after treatment to evaluate tear quality and diagnose eye dryness. These included the phenol red thread (PRT), tear break-up time (TBUT), tear osmolarity (saltiness), and tear ferning (TF) tests.

Tear ferning is used to help determine tear film health using a drop of tear fluid, which is allowed to dry on a microscope slide. Like most, if not all, bodily fluids, tears produce a characteristic crystallization pattern that, when dried, resembles a delicate fern leaf.

TF patterns manifest in relation to tear quality and are generally classified as one of four types, although alternate classification methods exist. Type I ferns, considered the healthiest pattern, exhibit extensive branching with no spaces between individual ferns. Type II ferns are smaller and more widely spaced. Type III ferns are incompletely formed, exhibiting minimal branching, while Type IV tear samples display no ferning at all.

High salt and high protein levels inhibit tear ferning, as does dry eye. Tear samples from people with dry eye issues or syndromes (i.e., Sjogren’s) typically exhibit Type III and IV ferning patterns. In contrast, Type I or Type II patterns are seen in tears from healthy, well-lubricated eyes.

Subjects in the current study presented at baseline with the expected tear ferning patterns, according to their group—dry or healthy eyes. Following the treatment period, however, TF grades improved significantly in the dry eye group.

Specifically, after supplementation with 5,000 IU of vitamin A every morning for just three days, TF grades were significantly decreased in subjects with dry eye, while osmolarity values were significantly increased (a desirable result for this test). PRT and TBUT test values also were improved in the dry eye group following vitamin A supplementation, although not significantly.

By contrast, in the control group of subjects with healthy eyes, all four test values remained relatively stable, with no significant differences observed in any parameter following the intervention compared with prior measurements.

Why Vitamin A Matters for Surface Eye Health

Vitamin A deficiency has long been associated with visual impairment and eye complaints, including dryness. Decades of research suggest that vitamin A supplementation may not only help to ameliorate dry eye symptoms but also to enhance the stability and smoothness of the tear film, improve visual acuity, and support adequate tear production while preventing excess watering.

It should be emphasized that natural vitamin A supplements derived from fish oil, and synthetic vitamin A supplements (retinyl palmitate), often derived from palm oil, should not be confused with beta carotene supplements. Beta-carotene is a plant-based precursor to vitamin A, but it is neither equivalent to nor has been shown to provide the same benefits as the preformed nutrient.

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Diana Allen, MS, CNS, is a clinical nutritionist in private practice and the Product Development Manager at Moss Nutrition. She is the author of numerous health articles and three booklets—Chia Seed, Kombucha, and Natural & Healthy Sweeteners (Woodland Publishing). Diana can be reached at diana@ mossnutrition.com or through her website www.eat2evolve.net.

Well Being Journal adapted the above excerpt from Moss Nutrition Digest (#48) “Hope for Dry Eyes: Tear Quality Improves with 5,000 IU Vitamin A Daily, ctd.” by Diana Allen, MS, CNS. Printed with permission from the author.

REFERENCES

National Eye Institute. “Dry Eye.” Accessed August 6, 2025. https://www. nei.nih.gov/learn-about-eye-health/ eye-conditions-and-diseases/dry-eye.

Alanazi SA, El-Hiti GA, et al. “Effects of short-term oral vitamin A supplementation on the ocular tear film in patients with dry eye.” Clin Ophthalmol. 2019 Apr 10;13:599-604.