Which Vitamin Causes Night Blindness? The Link to Vitamin A Explained

December 13, 2025 •

4 min read

An estimated 250,000–500,000 children become blind each year due to vitamin A deficiency, which is the leading cause of preventable childhood blindness worldwide. This essential nutrient plays a crucial role in vision, and its absence directly results in the condition known as night blindness or nyctalopia.

Quick Summary

A deficiency in Vitamin A is the primary cause of night blindness, a condition that impairs low-light vision. It hinders the production of rhodopsin, the retinal pigment necessary for seeing in dim light.

Key Points

Vitamin A is essential for night vision: The retina's rod cells need Vitamin A to create rhodopsin, the pigment for low-light vision.
Deficiency leads to nyctalopia: An inadequate supply of Vitamin A prevents the regeneration of rhodopsin, causing impaired night vision.
Beyond vision, deficiency causes other issues: Symptoms can include dry skin, weakened immunity, and stunted growth in children.
Diet and malabsorption are key risk factors: Lack of Vitamin A in the diet or conditions affecting fat absorption increase risk.
Night blindness can be treated: Supplementation and dietary changes can often reverse night blindness caused by a deficiency.
Prevention is a global health priority: Increasing Vitamin A intake is a primary strategy to prevent night blindness, especially in vulnerable populations.

The Core Connection: Vitamin A and Retinal Function

Your ability to see in both bright and low light relies on photoreceptor cells in your retina. These are divided into cones, for bright light and color vision, and rods, for dim light and motion detection. For the rod cells to work effectively, they need a light-sensitive pigment called rhodopsin. Vitamin A is a vital precursor for synthesizing this pigment, making it central to the process of low-light vision.

How a Deficiency Impairs Night Vision

When you move from a bright environment to a dark one, your rod cells must regenerate rhodopsin to adapt. In a person with a Vitamin A deficiency, this regeneration process is compromised due to the lack of the necessary raw materials. As a result, the rod cells cannot function properly, leading to impaired night vision, slow adaptation to darkness, and the classic symptoms of night blindness.

Symptoms and Risk Factors Beyond Vision

While poor night vision is a tell-tale sign, a Vitamin A deficiency can affect other systems in the body, as this fat-soluble vitamin is involved in numerous physiological processes.

Symptoms of Vitamin A Deficiency

Eye and Vision Problems: Beyond night blindness, symptoms can progress to dry eyes (xerophthalmia), foamy patches on the whites of the eyes (Bitot's spots), and in severe cases, corneal damage and permanent blindness.
Skin Issues: A lack of Vitamin A can lead to dry, scaly, or rough skin, and the development of hardened, small bumps on the skin, a condition called follicular hyperkeratosis or phrynoderma.
Weakened Immune System: Vitamin A supports immune function by maintaining the health of mucosal barriers, and a deficiency can increase the risk of infections, particularly respiratory and gastrointestinal infections.
Stunted Growth: In children, a prolonged deficiency can lead to delayed growth and development.
Reproductive Issues: Vitamin A plays a role in reproduction, and a deficiency can lead to fertility problems and complications with pregnancy.

Factors Increasing Risk of Deficiency

Malnutrition: The most significant risk factor globally, primarily in developing countries with limited access to nutrient-rich food.
Malabsorption Disorders: Conditions like cystic fibrosis, Crohn's disease, and chronic diarrhea can prevent the body from properly absorbing fats and, therefore, fat-soluble vitamins like A.
Alcoholism: Excessive alcohol consumption can lead to liver damage, which impairs the liver's ability to store and metabolize Vitamin A.
Restrictive Diets: Severely restrictive diets, including certain vegan or highly limited eating plans, can lead to insufficient Vitamin A intake without careful planning.
Bariatric Surgery: Procedures that bypass portions of the small intestine can lead to fat malabsorption and subsequent Vitamin A deficiency.

Treatment and Prevention

If night blindness is caused by a Vitamin A deficiency, the condition is typically treatable and, if caught early, reversible. However, treatment and prevention strategies differ based on the underlying cause.

Treatment for Deficiency-Related Night Blindness

Treatment involves restoring the body's Vitamin A levels. This may include high-dose Vitamin A supplements prescribed by a healthcare provider for a short period, followed by regular maintenance doses. In cases where malabsorption is the issue, treating the primary condition is necessary.

Prevention Strategies

Consume a Balanced Diet: Focus on incorporating a variety of foods rich in both preformed Vitamin A and beta-carotene.
Manage Underlying Health Issues: For individuals with conditions affecting nutrient absorption, managing the primary illness is critical to maintaining adequate Vitamin A levels.
Regular Check-ups: Routine eye exams can help detect early signs of a deficiency or other conditions that might be contributing to night blindness.

Comparing Vitamin A Sources

To ensure adequate intake, it's helpful to understand the different forms of Vitamin A found in food.


Food Source Type	Examples of Foods	Vitamin A Form	Notes
Animal-Based	Beef liver, fish (salmon, herring), eggs, dairy products (milk, cheese)	Preformed Vitamin A (Retinol)	This form is highly bioavailable and easily used by the body.
Plant-Based	Carrots, sweet potatoes, spinach, kale, mangoes, cantaloupe	Provitamin A (Carotenoids like Beta-Carotene)	The body converts these plant pigments into retinol. Absorption can vary.

Conclusion: The Definitive Link to Vitamin A

In summary, Vitamin A deficiency is the clear answer to which vitamin causes night blindness. Its role in producing the crucial retinal pigment rhodopsin is fundamental to the mechanism of low-light vision. While night blindness is a significant and distressing symptom, it is often a reversible condition when caused by a dietary deficiency. By ensuring sufficient intake of Vitamin A through a balanced diet or supplements as advised by a medical professional, individuals can protect their vision and overall health. Addressing malabsorption disorders and other risk factors is also vital for prevention. The global effort to combat this preventable cause of blindness highlights the importance of this single, vital nutrient.

Frequently Asked Questions

The medical term for night blindness is nyctalopia, a condition marked by difficulty seeing in dim light or darkness.

Vitamin A is converted into retinal in the retina, where it combines with opsin to form rhodopsin. This molecule is essential for the function of rod cells, which are responsible for low-light vision.

Preformed Vitamin A (retinol) is found in animal products like liver and dairy, while provitamin A carotenoids, which the body converts to retinol, are found in plants like carrots, sweet potatoes, and leafy greens.

Yes, excessive intake of preformed Vitamin A, particularly from supplements, can be toxic and lead to health problems. The body regulates the conversion of plant-based carotenoids, making toxicity from fruits and vegetables rare.

Yes, while Vitamin A deficiency is a common cause, night blindness can also be a symptom of other conditions like cataracts, retinitis pigmentosa, or severe nearsightedness.

If night blindness is due to a refractive error like myopia (nearsightedness), corrective lenses may help. However, if caused by a retinal disease or Vitamin A deficiency, glasses will not correct the underlying problem.

It is primarily due to malnutrition resulting from inadequate access to and intake of foods rich in Vitamin A, which can be exacerbated by infectious diseases.