Which of the following is NOT listed as a cause of Aqueous Deficient Dry Eye?

• A. Immune-mediated
• B. Trauma
• C. Infectious distemper
• D. Vitamin A deficiency

Answer: (D)

Aqueous deficient dry eye occurs when the lacrimal glands fail to produce enough aqueous component of the tear film, leading to a visibly reduced tear volume. The most common causes are autoimmune destruction of the lacrimal glands, direct trauma to the glands or their neural supply, and infections that inflame the lacrimal tissue, such as canine distemper. Vitamin A deficiency, on the other hand, primarily affects the ocular surface by reducing goblet cell density and promoting conjunctival squamous metaplasia, which disrupts mucin production and tear film quality rather than markedly lowering the aqueous tear production. So while vitamin A deficiency can contribute to ocular surface dryness, it is not a recognized cause of decreased lacrimal aqueous secretion, making it the correct choice for NOT being listed as a cause of aqueous deficient dry eye.