Question

Given below is the classification of Xerophthalmia by ocular signs. Arrange them in the correct sequence
A. Corneal Xerosis
B. Bitot spot
C. Keratomalacia
D. Night blindness
E. Conjunctival Xerosis
F. Corneal scar
Choose the correct answer from the option given below:

• A. B, D, A, C, F, E
• B. E, B, A, F, C, D
• C. D, E, B, A, C, F
• D. B, E, A, C, D, F

Hint:

WHO Xerophthalmia Stages: XN (Night blindness) $\rightarrow$ X1A (Conjunctival xerosis) $\rightarrow$ X1B (Bitot spot) $\rightarrow$ X2 (Corneal xerosis) $\rightarrow$ X3 (Keratomalacia) $\rightarrow$ XS (Corneal scar).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
World Health Organization (WHO) staging classification of Vitamin A deficiency (Xerophthalmia) ocular manifestations in increasing order of clinical severity.
Key Formula or Approach:
\[ \text{XN (Night blindness)} \rightarrow \text{X1A (Conjunctival xerosis)} \rightarrow \text{X1B (Bitot's spots)} \rightarrow \text{X2 (Corneal xerosis)} \rightarrow \text{X3 (Keratomalacia)} \rightarrow \text{XS (Corneal scar)} \]

Step 2: Detailed Explanation:
The chronological progression of ocular clinical signs in Xerophthalmia according to WHO staging:
1. D. Night Blindness (XN): Earliest functional symptom (impaired dark adaptation).
2. E. Conjunctival Xerosis (X1A): Dryness, loss of luster, and wrinkling of conjunctiva.
3. B. Bitot's Spots (X1B): Triangular, foamy, silvery-grey patches on bulbar conjunctiva.
4. A. Corneal Xerosis (X2): Dry, hazy, non-wettable cornea.
5. C. Keratomalacia (X3A/X3B): Liquefactive necrosis and ulceration of cornea (leads to irreversible blindness).
6. F. Corneal Scar (XS): Permanent healed scar tissue following ulceration.
Correct sequence: D $\rightarrow$ E $\rightarrow$ B $\rightarrow$ A $\rightarrow$ C $\rightarrow$ F.

Step 3: Final Answer:
Therefore, the correct sequence is D, E, B, A, C, F, matching option (C).