The Biochemistry Online – Free Online Lectures for Medical, Dental and Allied Health Sciences students by the Biochemistry Club.
When deficiency of Vitamin A occurs, following manifestations may appear:
1. Nyctalopia or Night Blindness
- Visual Activity is decreased in dim light, cannot read/drive in poor light.
- Dark adaptation time is increased.
- Conjunctiva becomes dry, thick & wrinkled.
- Corneal ulceration may develop.
- The cornea gets keratinized and loses its transparency (keratomalacia).
3. Bitot’s Spots
- Greyish white triangular patches on conjunctiva start to form.
- These are called Bitot’s spots.
- These are reversible if treated early.
4. Keratinization of Skin & Mucous Membrane
- Follicular hyperkeratosis results from hyperkeratinization of the epithelium lining.
- The follicles, skin is rough.
- Gastrointestinal, Respiratory & Genitourinary tracts have keratinizing metaplasia.
- Epithelium is atrophied.
- Urinary calculi due to keratinization of epithelium may form.
5. Growth retardation
- Skeletal growth retardation can be seen due to the defective synthesis of chondroitin sulfate.