Understanding the Link Between Nutrition and Eye Health: What are vitamin A deficiency spots in the eye?

October 7, 2025 •

2 min read

Vitamin A deficiency is the leading preventable cause of childhood blindness in developing countries, affecting hundreds of thousands of children each year. A key clinical sign is knowing what are vitamin A deficiency spots in the eye, also known as Bitot's spots. These are critical markers of a severe nutritional issue that requires immediate attention.

Quick Summary

Bitot's spots are white, foamy patches on the conjunctiva, signifying a significant vitamin A deficiency and a stage of xerophthalmia. Early detection is crucial to prevent progression to more severe, potentially blinding, eye conditions. Treatment focuses on addressing the underlying nutritional cause.

Key Points

Marker of VAD: Bitot's spots are a specific, visible sign of a significant and often prolonged vitamin A deficiency (VAD).
Caused by Keratin Buildup: The spots are patches of dried, keratinized conjunctival tissue, caused by the transformation of mucus-secreting cells into a skin-like surface.
Associated with Xerophthalmia: Bitot's spots are part of a broader clinical condition called xerophthalmia, which also includes night blindness and corneal dryness.
Requires Urgent Intervention: The appearance of these spots indicates a severe deficiency that, if untreated, can progress to corneal ulcers and irreversible blindness.
Treatment and Prevention through Nutrition: Addressing the underlying vitamin A deficiency is the standard treatment, but long-term prevention depends on a diet rich in both preformed vitamin A (from animal sources) and provitamin A carotenoids (from plant sources).

What are Bitot's spots?

Bitot's spots are a characteristic sign of vitamin A deficiency (VAD) within the spectrum of xerophthalmia, classified by the World Health Organization (WHO). They appear as discrete, dry, foamy, or cheesy patches on the conjunctiva, the clear membrane covering the white part of the eye. This texture is due to keratin buildup on the ocular surface. Gas-forming bacteria, particularly Corynebacterium xerosis, can contribute to the foamy look in the dry eye environment. Bitot's spots are not easily removed and may leave permanent scarring even after treatment, indicating a prolonged deficiency. They are typically found on the temporal (outer) conjunctiva, the area exposed when the eye is open.

The pathological process behind Bitot's spots

Vitamin A is vital for healthy epithelial tissues in the eye. Severe VAD causes squamous metaplasia, transforming the normal, moist conjunctival epithelium into dry, keratinized tissue similar to skin. This process eliminates mucus-producing goblet cells, resulting in the dry patches of Bitot's spots.

The spectrum of eye-related vitamin A deficiency (xerophthalmia)

Bitot's spots are part of xerophthalmia, a range of eye conditions caused by VAD. The spectrum includes night blindness, conjunctival and corneal dryness, and in severe cases, corneal ulceration, keratomalacia, and scarring, which can lead to permanent vision loss. More details on the spectrum of eye signs can be found on {Link: PMC pmc.ncbi.nlm.nih.gov}.

Causes and diagnosis of Bitot's spots

Bitot's spots strongly suggest VAD, but the causes vary. In developing countries, it's primarily due to insufficient dietary intake of vitamin A. Vulnerable groups include young children and pregnant or lactating women. In developed countries, VAD is rarer and usually linked to conditions that impair nutrient absorption, storage, or transport. These include gastrointestinal disorders, liver disease, chronic alcoholism, and severe restrictive diets.

Diagnosis typically involves a clinical eye examination. Blood tests for serum retinol and retinol-binding protein can confirm VAD. A detailed medical and dietary history is essential to identify the underlying cause.

Treatment and prevention

Treating Bitot's spots and xerophthalmia involves addressing the underlying vitamin A deficiency, often through supplementation under medical supervision. Improvement may be observed, though the spots may not fully disappear, indicating past deficiency.

Prevention focuses on diet. Animal sources like liver, eggs, and fortified products provide preformed vitamin A, while plant sources like carrots, sweet potatoes, spinach, and kale offer provitamin A carotenoids. In areas with high malnutrition, large-scale supplementation programs are crucial. A table comparing Bitot's spots to other conjunctival lesions can be found on {Link: PMC pmc.ncbi.nlm.nih.gov}.

Conclusion

Bitot's spots are a key indicator of vitamin A deficiency, a condition that can progress to severe eye damage and irreversible blindness, particularly in children. Proper diagnosis and prompt treatment addressing the underlying deficiency are essential. While treatment helps, the spots can leave permanent marks. A diet rich in vitamin A from diverse sources is crucial to prevent this preventable cause of vision loss.

Frequently Asked Questions

The main cause of these spots, known as Bitot's spots, is a severe vitamin A deficiency, which causes the eye's conjunctival tissue to undergo a process called squamous metaplasia, resulting in keratin buildup.

Yes, Bitot's spots can often be effectively managed by addressing the underlying vitamin A deficiency under medical guidance. However, while the active deficiency is treated, the spots may not completely disappear and can leave a permanent impression on the conjunctiva.

The earliest and most sensitive sign of vitamin A deficiency is night blindness, or difficulty seeing in dim light. Bitot's spots typically appear as the deficiency progresses.

The foamy appearance is often caused by gas produced by gas-forming bacteria, particularly Corynebacterium xerosis, which accumulate in the keratinized patches of the conjunctiva.

To prevent VAD, consume foods rich in preformed vitamin A like liver, eggs, and fortified dairy products, as well as provitamin A carotenoids from sources like carrots, sweet potatoes, spinach, and kale.

Diagnosis is typically made through a clinical eye examination by a doctor. A medical history focusing on diet and potential malabsorption issues is also critical. In some cases, blood tests to measure serum retinol levels are used to confirm the deficiency.

While rare, studies have shown that lesions clinically indistinguishable from Bitot's spots can occur in individuals with normal vitamin A levels, particularly those with other anterior segment eye conditions or prolonged exposure to environmental irritants.