Can vitamin A deficiency cause vision problems?

Vitamin A Deficiency and Vision Problems

Yes, vitamin A deficiency definitively causes vision problems, including night blindness, xerophthalmia, and potentially permanent blindness if left untreated. 1

Clinical Manifestations of Vitamin A Deficiency on Vision

• Night blindness (nyctalopia) is the earliest ocular symptom, caused by insufficient rhodopsin synthesis 1
• Bitot spots appear as gray/white, foamy lesions on the conjunctiva 1
• Xerophthalmia (dryness of the conjunctiva and cornea) develops as deficiency progresses 1
• Keratomalacia (keratin deposits with inflammation) can develop, leading to corneal damage 1
• If untreated, the condition can progress to complete blindness through corneal maceration, secondary infection, and permanent damage 1, 2

Pathophysiology

Vitamin A is essential for:

• Synthesis of rhodopsin (visual purple) in the retina, which is critical for night vision 1
• Maintenance of epithelial tissue integrity, including in the eye 3
• Normal immune function, which helps prevent secondary infections that can worsen eye damage 1

Risk Factors for Vitamin A Deficiency

Vitamin A deficiency should be suspected in patients with:

• Liver disease: Chronic liver disease shows high prevalence of vitamin A deficiency; severity increases with disease progression 1
• Chronic alcohol consumption: Depletes liver vitamin A stores 1
• Malabsorption conditions: Including short bowel syndrome, cystic fibrosis, celiac disease, and chronic diarrhea 1
• Bariatric surgery: Particularly malabsorptive procedures like Roux-en-Y gastric bypass and biliopancreatic diversion 1
• Highly restrictive diets: Especially those lacking animal products or fortified foods 3
• Chronic kidney disease: Requires monitoring as vitamin A levels can fluctuate 1

Diagnosis

• Serum retinol levels should be measured in patients with suspected deficiency 1
• During inflammation, retinol-binding protein (RBP) release from the liver is reduced, which may affect serum retinol levels 1
• Adjustment for inflammatory biomarkers (CRP, AGP) may be necessary for accurate assessment 1

Treatment

For vitamin A deficiency with visual symptoms:

• Adults: Oral supplementation with vitamin A 10,000-25,000 IU daily for 1-2 weeks is recommended for clinical improvement 1
• Higher doses or intramuscular injections may be needed for patients experiencing night blindness 1
• Recheck vitamin A levels after 3 months of treatment 1
• For vitamin A deficiency that doesn't respond to oral treatment, refer to a specialist for assessment and consideration of intramuscular vitamin A injections 1
• Ophthalmology referral should be considered for patients with visual symptoms 1

Prevention in High-Risk Groups

• Regular monitoring of vitamin A status in high-risk patients 1
• Multivitamin supplements containing vitamin A for patients after bariatric procedures 1
• Special attention to pregnant women and children in developing countries where deficiency is endemic 1, 4

Caution

• Avoid excessive supplementation as vitamin A toxicity can occur with prolonged high doses (>25,000 IU daily for >6 months) 1
• The upper limit for vitamin A is set at 10,000 IU daily for women of childbearing age 1
• During pregnancy, the β-carotene form of vitamin A is preferred over retinol, especially during the first trimester, to avoid teratogenic risk 1

Early detection and treatment of vitamin A deficiency are crucial to prevent permanent visual impairment, as ocular damage can become irreversible if treatment is delayed 3, 5.