A 4-year-old child from a rural area presents with a history of poor night vision. Examination shows dry, foamy, triangular plaques on the temporal bulbar conjunctiva. Which cell type is lost early in this deficiency?

• A Goblet cells of the conjunctival epithelium ✓
• B Keratinocytes of the corneal epithelium
• C Melanocytes of the limbus
• D Endothelial cells of the conjunctival vessels

Explanation

Vitamin A maintains epithelial differentiation; deficiency causes squamous metaplasia with loss of mucus-secreting goblet cells, producing xerosis and the foamy Bitot spot seen here. Night blindness precedes it because of impaired resynthesis of rhodopsin from retinal. The corneal keratinocyte change (keratomalacia) is a late complication, not the earliest loss, which rules out option B.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.