This document discusses the WHO classification of xerophthalmia, a condition caused by vitamin A deficiency. It defines xerophthalmia and explains its etiology. The WHO classification includes 7 stages: XN (night blindness), X1A (conjunctival xerosis), X1B (Bitot's spots), X2 (corneal xerosis), X3A & 3B (keratomalacia), XS (corneal scarring), and XF (fundus changes). Each stage is described in 1-2 sentences with its key symptoms and clinical presentation.

1. XEROPHTHALMIA -
WHO CLASSIFICATION
Dr. Madhuri. P
Post Graduate
Dept of Ophthalmology

2. Objectives
• Define XEROPHTHALMIA
• Etiology
• WHO classification

3. Definition
• Xerophthalmia is defined as all the ocular manifestations of
vitamin A deficiency, including not only the structural
changes affecting the conjunctiva, cornea and occasionally
retina, but also the biophysical disorders of retinal rods and
cones functions.

4. Etiology
• Dietary deficiency of vitamin A
• Defective absorption of vitamin A
• Vit A is essential for the synthesis of retinal photopigments
& conjunctival glycoproteins
• RHODOPSIN > visual cycle > Delayed dark adaptation/
Night blindness
• Conjunctival epithelial dysfunction > Ocular surface dryness

5. XN
Night blindness
• earliest symptom of
xerophthalmia in
children.
• to be elicited by
taking detailed history
from the guardian

6. X1A
Conjunctival xerosis
• one or more patches of dry, lustreless,
nonwettable conjunctiva
• ‘emerging like sand banks at receding tide’
when the child ceases to cry.
• These patches almost always involve the
interpalpebral area
• may be associated with conjunctival
thickening, wrinkling and pigmentation

7. X1B
Bitot spots
• raised, silvery white, foamy,
triangular patch of keratinised
epithelium, situated on the bulbar
conjunctiva in the interpalpebral
area
• It is usually bilateral and temporal

8. X2
Corneal xerosis
• punctate keratopathy which
begins in the lower nasal
quadrant,followed by haziness
and/or granular pebbly dryness
• Involved cornea lacks lustre.

9. X3A &X3B
Keratomalacia
• due to colliquative necrosis
• characteristically circular, with steep
margins and are sharply demarcated
• X3A usually heal, leaving some useful
vision.
• X3Bbcommonly result in blindness

10. XS & XF
Corneal scars & Xero fundus
• Stromal defects results in corneal scars of
different densities and sizes
• which may or may not cover the pupillary
area
• XF is characterized by typical seed-like,
raised, whitish lesions scattered uniformly
over the part of the fundus at the level of
optic disc

11. BITOT'S SPOTS - X1B Corneal scarring - XS

12. WHO classification
• XN - Night blindness
• X1A - Conjunctival xerosis
• X1B - BITOT'S spots
• X2 - Corneal xerosis
• X3A & 3B - Keratomalacia
• XS - Corneal scarring
• XF - Fundus changes