Is vitamin A deficiency a cause of myopia (nearsightedness)?

Vitamin A Deficiency Does Not Cause Myopia

No, vitamin A deficiency does not cause myopia (nearsightedness). Vitamin A deficiency causes a distinct set of vision problems—primarily night blindness, xerophthalmia, and potentially permanent blindness from corneal damage—but these are fundamentally different pathologic processes from myopia, which is a refractive error caused by excessive axial eye length or corneal curvature 1, 2, 3.

The Vision Problems Actually Caused by Vitamin A Deficiency

Vitamin A deficiency produces a specific cascade of ocular surface and retinal pathology:

• Night blindness is the earliest symptom, resulting from insufficient rhodopsin synthesis in the retina (rhodopsin is the photopigment essential for low-light vision) 1, 2, 3
• Bitot spots appear as gray/white foamy lesions on the conjunctiva, representing keratinized epithelium 1, 2, 3
• Xerophthalmia (severe dry eye) develops from loss of mucus-secreting goblet cells and reduced tear production 3, 4
• Corneal keratinization and ulceration occur in more advanced deficiency 3, 4
• Keratomalacia (corneal softening and melting) can progress to permanent blindness through corneal maceration and secondary infection 1, 2, 3

These conditions reflect vitamin A's essential role in maintaining normal epithelial differentiation and retinal photoreceptor function—mechanisms entirely separate from the refractive errors that define myopia 1, 4.

Evidence Regarding Vitamin A and Myopia

The most recent and rigorous evidence directly addresses this question:

• A 2024 Mendelian randomization study and meta-analysis found no convincing evidence of a causal relationship between vitamin A supplementation and myopia risk (OR = 0.99,95% CI 0.82-1.20, p = 0.40) 5
• A 2020 prospective cohort study (Raine Study) found that while adequate vitamin A intake showed a trend toward lower myopia prevalence, this association became insignificant after adjusting for confounders (OR 0.59,95% CI 0.98-2.52, p = 0.06) 6
• Interestingly, a 2022 cross-sectional study using machine learning found that high serum vitamin A levels were associated with increased prevalence of high myopia (adjusted OR = 1.46 per 1 µmol/L increment, 95% CI 1.01-2.10), though the authors cautioned about potential Type I error from multiple testing 7

Clinical Context: Different Diseases, Different Populations

The distinction becomes clearer when examining where these conditions occur:

• In low-income countries, vitamin A deficiency causes cataracts and corneal blindness from infectious disease or nutritional deficiency 1
• In high-income countries, myopia is epidemic (particularly in East Asian populations) but vitamin A deficiency is rare except in specific malabsorption conditions 1
• Myopia is primarily driven by genetic factors, near-work activities, and reduced outdoor time—not nutritional deficiency 1, 5

High-Risk Populations for Vitamin A Deficiency (Not Myopia)

Monitor vitamin A status in patients with:

• Chronic liver disease (prevalence increases with disease severity; 69.8% of liver transplant candidates are deficient) 1, 3
• Malabsorption syndromes: short bowel syndrome, cystic fibrosis, celiac disease, chronic diarrhea 1, 3
• Bariatric surgery, particularly malabsorptive procedures (BPD/DS, RYGB) 3
• Chronic alcohol consumption (depletes hepatic stores, though serum levels may remain falsely normal) 1, 3
• Chronic kidney disease (requires monitoring as levels fluctuate unpredictably) 1, 3

Critical Clinical Pitfall

Serum retinol levels may remain normal despite depleted liver stores, particularly in chronic alcohol consumption and during inflammatory states when retinol-binding protein release is reduced 3. This creates a false sense of adequacy and can delay diagnosis of true deficiency 3.

Treatment of Vitamin A Deficiency (When Present)

• Oral supplementation: 10,000-25,000 IU daily for 1-2 weeks for clinical improvement 2
• Higher doses or intramuscular injections may be needed for patients with night blindness 2
• Recheck levels after 3 months of treatment 2
• Avoid excessive supplementation: upper limit is 10,000 IU daily for women of childbearing age due to teratogenic risk 1, 2