Vitamin A deficiency affects the conjunctiva, cornea and retina. Here I will concentrate on the anterior eye problems.

Vitamin A deficiency occurs in developing countries and I have seen the ocular effects during my work in Asia and Africa. The damage to the ocular surface is called xerophthalmia-xeros = dry, ophthalmos = eye in Ancient Greek. There are other causes of xerophthalmia other than vitamin A deficiency.

The conjunctiva becomes dry, thick and wrinkled. If untreated, it can lead to corneal ulceration and ultimately to blindness.

World Health Organization classified xerophthalmia into following stages:

  • XN-Night blindness
  • X1A-Conjunctival xerosis
  • X1B-Bitot spots
  • X2-Corneal xerosis
  • X3A-Corneal ulceration/keratomalacia, involving less than one-third of the cornea
  • X3B-Corneal ulceration/keratomalacia, involving more than one-third of the cornea
  • XS-Corneal scar due to xerophthalmia
  • XF-Xerophthalmic fundus

Each year approximately 8 to 10 million children worldwide, 3 to 5 years in age, develop milder xerophthalmia manifested by night blindness or conjunctival xerosis associated with malnutrition.

Bitot’s spots are the buildup of keratin-fibrous structural protein-located superficially in the conjunctiva. They can be oval, triangular or irregular in shape.

Animal liver and dairy products are very rich sources of vitamin A but this is of no use for those people who choose not to eat meat and other animal products.

The human body can produce vitamin A from carotenoids found in plants such as beta-carotene and alpha-carotene. These are collectively known as provitamin A. However, about 45% of people carry a genetic mutation that significantly reduces their ability to convert provitamin A into vitamin A. Vegetable sources of provitamin A are sweet potato, winter squash, kale and carrots. But people with the genetic mutation may still have vitamin A deficiency even if they consume these vegetables. Vitamin A supplements are useful for these people.


Submit a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

If you like EyeTools Questions of the Day…

Children’s Eye Examinations
How to Run a Successful Low Vision Clinic
How to Run a Successful Optometry Practice



– Optometry students
– Pre-registration and novice optometrists
– Optometrists returning to work
– Junior eye doctors
– Dispensing opticians and orthoptists preparing for refraction exams
– Contact lens opticians, clinical assistants and eyecare educators

Improve your optometry skills with introductory & specialist instruction videos, topical live & recorded expert webinars, presentations and book reviews.

Start with the first section, ‘Pre-refraction procedures’ free, then choose a monthly or yearly subscription. To see English captions, click the CC button on any video.