Bitot’s spots are distinct patches that appear on the conjunctiva, the white part of the eye. These spots are triangular and have a dry, foamy, or whitish look. They are made of keratin, a protein, that builds up on the surface of the eye. The appearance of these spots is a clinical indicator of a vitamin A deficiency.
The Connection to Vitamin A Deficiency
Bitot’s spots are a hallmark sign of a severe deficiency in vitamin A. This nutrient maintains the health of the conjunctiva. A lack of vitamin A disrupts the function of specialized goblet cells within the conjunctiva. These cells secrete mucus that lubricates the eye’s surface, and their impairment leads to dryness.
This process leads to the accumulation of keratin mixed with bacteria. The bacteria release gas, which contributes to the foamy appearance of the spots. This underlying dryness is part of a broader condition called xerophthalmia, which means “dry eye” and includes a range of eye problems caused by vitamin A deficiency.
The deficiency affects vision in other ways. One of the earliest symptoms to appear, often before Bitot’s spots are visible, is night blindness, or nyctalopia. This occurs because vitamin A is needed to produce certain pigments in the retina that allow the eyes to see in low light. Without enough vitamin A, the retina cannot function correctly in the dark.
Diagnosis and Reversibility
The diagnosis of Bitot’s spots is straightforward and is made during a physical eye examination. The distinctive foamy, triangular patches are a clear indicator. A physician will also ask about the patient’s diet, health history, and other symptoms like difficulty seeing at night to support the diagnosis.
To confirm the cause, a blood test can measure the level of retinol, the active form of vitamin A in the blood. This provides a definitive measure of the deficiency’s severity. People with a history of malnutrition, alcohol abuse, or disorders affecting nutrient absorption should seek medical evaluation if they notice eye changes.
The condition is treatable, and the spots themselves are reversible. The standard treatment involves high-dose vitamin A supplementation, which must be administered under medical supervision. Once vitamin A levels are restored, the abnormal keratinized cells on the conjunctiva are replaced by healthy tissue, and the Bitot’s spots disappear.
Dietary Sources of Vitamin A for Prevention
Preventing a vitamin A deficiency involves consuming a diet rich in this nutrient. Vitamin A is obtained from food in two primary forms. Preformed vitamin A, known as retinol, is found in animal-based products like liver, eggs, and dairy products.
The other form is provitamin A carotenoids, which are plant-based pigments that the body can convert into vitamin A. These are abundant in many brightly colored fruits and vegetables. Foods like carrots, sweet potatoes, kale, and spinach are particularly high in carotenoids. Including a variety of these foods in a regular diet helps maintain adequate vitamin A levels.