Bitot's spots are the buildup of

keratin Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up scales, hair, nails, feathers, ho ...

located superficially in the

conjunctiva The conjunctiva is a thin mucous membrane that lines the inside of the eyelids and covers the sclera (the white of the eye). It is composed of non-keratinized, stratified squamous epithelium with goblet cells, stratified columnar epithelium ...

of human's eyes. They can be oval, triangular or irregular in shape. The spots are a sign of

vitamin A deficiency Vitamin A deficiency (VAD) or hypovitaminosis A is a lack of vitamin A in blood and tissues. It is common in poorer countries, especially among children and women of reproductive age, but is rarely seen in more developed countries. Nyctalopia (ni ...

and associated with drying of the

cornea The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Along with the anterior chamber and lens, the cornea refracts light, accounting for approximately two-thirds of the eye's total optical ...

. In 1863, the French physician Pierre Bitot (1822–1888) first described these spots. The spots may abate under replacement therapy. In ancient Egypt, this was treated with animal liver, which is where vitamin A is stored.

Causes

Major cause of Bitot's spot is vitamin A deficiency (VAD). Rarely, pellegra due to deficiency of vitamin B₃ (niacin) may also cause Bitot's spots.

Treatment

VAD is commonly treated with oral vitamin A supplements. Improvement of Bitot's spots is seen with high-dose vitamin A therapy. Bitot's spots non-responsive to vitamin A therapy may be removed surgically.

References

External links

Eye diseases Vitamin deficiencies {{eye-stub