What Does Vitamin A Do for the Eyes?

December 25, 2025 •

3 min read

According to the World Health Organization, vitamin A deficiency is the leading cause of preventable blindness in children globally. This highlights the indispensable functions that vitamin A performs to maintain eye health and prevent severe vision loss, from aiding night vision to protecting the cornea.

Quick Summary

Vitamin A is essential for eye health, playing a key role in forming pigments for the retina to enable low-light vision and in maintaining a clear cornea to prevent dryness and infection. Deficiency can lead to night blindness and severe corneal damage.

Key Points

Night Vision: Vitamin A is a core component of rhodopsin, a pigment in retinal rod cells crucial for seeing clearly in low-light conditions.
Corneal Health: It helps maintain the health of the cornea and conjunctiva, protecting the eye's surface from dryness and infection.
Prevents Xerophthalmia: A deficiency can lead to xerophthalmia, a progressive eye disease beginning with night blindness and potentially causing irreversible blindness.
Protects Against Macular Degeneration: As an antioxidant, vitamin A and its carotenoid precursors can help protect against age-related macular degeneration (AMD).
Dietary Sources: Vitamin A comes in two forms: preformed retinol from animal products and provitamin A carotenoids from plant sources like carrots and spinach.
Supports Immune Function: The vitamin also supports the immune system, protecting the eyes from infections.
Deficiency Indicators: Early signs of vitamin A deficiency often include night blindness and dry eyes.

The Core Function: How Vitamin A Supports Vision

Vitamin A is crucial for a healthy visual system, particularly its role in the visual cycle within the retina. In the rod cells of the retina, a form of vitamin A called retinal is needed to create rhodopsin, a pigment essential for seeing in low light. Light changes the retinal molecule, sending signals to the brain and enabling vision. A lack of vitamin A means insufficient rhodopsin production, leading to night blindness, an early sign of deficiency.

Beyond Night Vision: Other Key Roles for Eye Health

Vitamin A also maintains the health of the cornea and conjunctiva, the protective outer layers of the eye. It prevents dryness and damage, helping to ward off infections. Without enough vitamin A, these tissues can dry out in a condition called xerophthalmia, potentially causing corneal ulcers, scarring, and permanent blindness. Furthermore, vitamin A's antioxidant properties, especially from beta-carotene, protect the eyes from damage by free radicals, which are linked to age-related conditions like macular degeneration and cataracts.

Deficiency Symptoms and Sources

Recognizing vitamin A deficiency symptoms is important, particularly in areas where it is common.

Signs of Deficiency

Night Blindness: Difficulty seeing in low light.
Dry Eyes: Lack of tear production leads to dryness and irritation.
Bitot's Spots: Foamy patches on the whites of the eyes.
Corneal Damage: Severe cases can result in ulcers and blindness.

Sources of Vitamin A

Vitamin A comes from animal products as preformed vitamin A (retinol) and from plants as provitamin A carotenoids, which the body converts.

Animal Sources: Liver, oily fish, eggs, dairy.
Plant Sources: Carrots, sweet potatoes, spinach, leafy greens.

Comparative Look at Vitamin A and Other Eye Nutrients

Vitamin A is vital, but other nutrients also support eye health. The table below compares vitamin A with key nutrients.


Feature	Vitamin A (Retinol & Carotenoids)	Lutein & Zeaxanthin	Omega-3 Fatty Acids	Vitamin C
Primary Function	Supports night vision; maintains cornea.	Filters blue light; protects macula.	Supports retinal structure; anti-inflammatory.	Antioxidant; collagen formation.
Key Role in Vision	Low light vision; prevents dryness.	Protects against AMD.	May reduce diabetic retinopathy; relieve dry eye.	May lower cataract risk.
Main Dietary Sources	Liver, dairy, carrots, sweet potatoes.	Leafy greens, egg yolks.	Oily fish, flaxseed.	Citrus fruits, broccoli.
Deficiency Concern	Night blindness, xerophthalmia, blindness.	Lower levels linked to AMD risk.	Can contribute to dry eye.	Severe deficiency (scurvy) can affect eyes.

The Age-Related Eye Disease Study (AREDS)

The AREDS trial investigated high-dose vitamin supplements for AMD. The original formula with beta-carotene, vitamins C and E, and zinc slowed advanced AMD progression. However, AREDS2 replaced beta-carotene with lutein and zeaxanthin due to beta-carotene's link to lung cancer in smokers. AREDS2 was equally effective, highlighting the importance of specific carotenoids for macular health.

Conclusion

Vitamin A is essential for eye health, supporting night vision, maintaining the cornea, and providing antioxidant protection. A balanced diet with both animal and plant sources is the best way to prevent deficiency and support overall ocular function. While supplements can help in specific cases like AMD, nutrients from whole foods offer the most comprehensive approach to eye health.

Authoritative Resource on Vitamins and Eye Health

For more detailed information, the National Institutes of Health provides a fact sheet: Vitamin A and Carotenoids: Fact Sheet for Health Professionals.

Frequently Asked Questions

The primary role of vitamin A is to help form rhodopsin, a light-sensitive pigment protein found in the rod cells of the retina. This process is essential for adapting to low-light conditions and for night vision.

Yes, severe and prolonged vitamin A deficiency can lead to irreversible blindness. It starts with night blindness and can progress to severe corneal damage, such as ulceration and scarring, a condition called xerophthalmia.

Preformed vitamin A, or retinol, is found in animal products and can be used directly by the body. Provitamin A, mainly in the form of beta-carotene, is found in plants and must be converted by the body into the active form as needed.

Yes, carrots are rich in beta-carotene, a provitamin A carotenoid that the body converts into vitamin A. This supports eye health and function, particularly night vision. However, many other foods also contain high levels of vitamin A.

Yes, excessive intake of preformed vitamin A, especially from supplements, can be toxic and cause serious health problems, including liver damage and vision disturbances. It is crucial not to exceed the recommended daily upper limit.

Yes, antioxidant nutrients, including beta-carotene, have been shown to help reduce the risk of advanced AMD progression. The AREDS2 formulation for AMD uses lutein and zeaxanthin as a safer alternative to beta-carotene for smokers.

In addition to vitamin A, other beneficial nutrients for eyes include lutein and zeaxanthin, omega-3 fatty acids, and vitamins C and E, which function as antioxidants and structural components.