What vitamin deficiency causes dry eye syndrome?

Under normal circumstances, dry eye syndrome is closely related to deficiencies in multiple vitamins. Commonly deficient vitamins include vitamin A, B-complex vitamins, vitamin C, vitamin D, and vitamin E. The specific analysis is as follows:

1. Vitamin A: Vitamin A is a key nutrient for maintaining ocular surface health. It participates in the synthesis of mucin in tears and enhances the stability of ocular surface epithelial cells. Deficiency can lead to drying and shedding of the ocular mucosa, preventing even distribution of tears, directly causing symptoms such as dryness and foreign body sensation in the eyes.

2. B-Complex Vitamins: B-complex vitamins are involved in nerve metabolism and mucosal repair, helping maintain normal tear gland secretion function. When deficient, tear production decreases and the viscosity of tears declines. This may also be accompanied by abnormal periocular nerve sensations, making discomforts like eye dryness and soreness more pronounced, while simultaneously reducing resistance of the ocular surface.

3. Vitamin C: Vitamin C has strong antioxidant properties that protect ocular tissues from free radical damage and promote collagen synthesis, thus maintaining the stability of the tear film. Deficiency reduces antioxidant capacity on the ocular surface, leading to rapid tear film breakup. This not only worsens symptoms such as dryness and photophobia but may also increase the risk of ocular surface inflammation.

4. Vitamin D: Vitamin D plays a role in regulating immune function, and dry eye syndrome is often associated with chronic inflammation of the ocular surface. Vitamin D deficiency can cause ocular immune imbalance and intensified inflammatory responses, thereby impairing tear secretion and tear film function, triggering or exacerbating dry eye symptoms—particularly evident in autoimmune-related dry eye.

5. Vitamin E: As a fat-soluble antioxidant, vitamin E protects the integrity of ocular cell membranes and prevents oxidation of lipid components in tears, preserving the tear film's ability to retain moisture. Deficiency damages the lipid layer of the tear film, accelerating tear evaporation and quickly leading to classic dry eye symptoms such as dryness and stinging pain.

In daily diet, vitamin A can be supplemented through foods such as animal liver and egg yolks; B-complex vitamins can be obtained from lean meats and legumes; fresh fruits and vegetables are excellent sources of vitamin C; and nuts and deep-sea fish provide adequate amounts of vitamins E and D. A balanced, nutritious diet provides essential support for eye health and helps alleviate dry eye discomfort.