This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Conjuctiva, Subject name: Ophthalmology
Mucin tear film deficiency occurs in 
Select and explain. 
A. Keratoconjunctivitis sicca, B. Lacrimal gland removal, C. Canalicular block, D. Herpetic keratitis
D: Herpetic keratitis
Answer: D: Herpetic keratitis 
Explanation: Ans. (d) Herpetic keratitisRef: Khurana anatomy, 2/e, p. 389Soluble surfactant (Mucin) deficiency is caused by ocular surface disorders affecting the goblet cells which secrete mucus forming the innermost layer of the tear film. Herpes infection causes Keratoconjunctivitis and hence mucin deficiency.