Xerophthalmia
Ophthalmology & Nutritional Science: Vitamin A Deficiency
1. Pathophysiology
Xerophthalmia represents the ocular manifestations of Vitamin A (retinol) deficiency. Vitamin A is essential for the maintenance of specialized epithelia, including the conjunctiva and cornea. Deficiency leads to keratinization of these surfaces, resulting in ocular dryness and potential blindness.
2. Clinical Staging (WHO Classification)
| Stage | Key Clinical Finding |
|---|---|
| X1A | Conjunctival xerosis (dry, dull appearance of conjunctiva). |
| X1B | Bitot’s spots (foamy, keratinized triangular patches on the bulbar conjunctiva). |
| X2 | Corneal xerosis (loss of corneal luster). |
| X3A/X3B | Corneal ulceration and liquefactive necrosis (Keratomalacia). |
3. Forensic & Clinical High-Yield Pearls
- Early Symptom: Nyctalopia (night blindness) is frequently the earliest clinical symptom due to the role of Vitamin A in rhodopsin synthesis.
- Emergency: Keratomalacia is an ophthalmological emergency; immediate systemic high-dose Vitamin A is required to prevent permanent corneal perforation and vision loss.
- Public Health: Xerophthalmia is a significant cause of preventable childhood blindness in developing nations.
- Educational Resource: For comprehensive nutrition-related ophthalmology guidelines and clinical practice questions, visit mymedschool.org.