Dry cornea occurs because of the deficiency of:

Appeared in: AIIMS Delhi NO-2016

Explanation

Vitamin A is an essential fat-soluble vitamin required for maintaining healthy epithelial tissues, including those in the eye.
A deficiency of Vitamin A leads to xerophthalmia, a condition whose name literally means 'dry eye'.
The dryness of the cornea (corneal xerosis) is a direct result of the degeneration of mucus-producing goblet cells in the conjunctiva, which disrupts the normal tear film.
The earliest symptom of Vitamin A deficiency is typically night blindness (nyctalopia).

Option A: Vitamin B12 deficiency does not cause dry eyes. Its primary manifestations are neurological and hematological.
Option C: Vitamin B1 (Thiamine) deficiency is unrelated to corneal health. It causes Beriberi or Wernicke-Korsakoff syndrome.
Option D: Vitamin C deficiency causes Scurvy, which affects collagen synthesis, leading to issues with blood vessels, gums, and wound healing, not dry cornea.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Vitamin Deficiencies and Ocular Manifestations as background academic context rather than a clinical decision trigger.
Nurses play a vital role in identifying at-risk populations for Vitamin A deficiency, such as young children, pregnant women, and individuals with malabsorption disorders.
A key nursing intervention is patient education on dietary sources of Vitamin A, including green leafy vegetables (spinach), yellow/orange fruits and vegetables (carrots, mangoes, papaya), and animal sources (liver, eggs, milk).
In a clinical setting, a nurse's assessment should include asking about difficulty seeing at night, which is the earliest sign of deficiency.

How to Approach the Question

First, identify the key clinical sign presented in the question stem: 'Dry cornea'.
Next, link this sign to its underlying medical condition. 'Dry eye' is known as xerophthalmia, and 'dry cornea' is specifically corneal xerosis.
Systematically review the vitamins listed in the options and recall their primary deficiency diseases.
Evaluate Option A (Vitamin B12): Deficiency causes pernicious anemia and neuropathy.
Evaluate Option B (Vitamin A): Deficiency causes xerophthalmia (dry eyes) and night blindness.
Evaluate Option C (Vitamin B1): Deficiency causes Beriberi.

Concept Tested & Keywords

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E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart A (pp 1-232 of 464) p. 151-153

E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 2 — Subpart A (pp 1-239 of 478) p. 121-123

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