Corneal sensation is decreased in –
**Core Concept**
Corneal sensation is primarily mediated by the **ophthalmic branch of the trigeminal nerve (V1)**. This nerve is responsible for transmitting sensory information from the cornea to the brain. Decreased corneal sensation can be a sign of various neurological or ophthalmological conditions.
**Why the Correct Answer is Right**
The correct answer is related to a condition that affects the **trigeminal nerve**, specifically the ophthalmic branch. This condition can lead to decreased corneal sensation due to impaired nerve function. The **herpes zoster virus** can cause herpes zoster ophthalmicus, which affects the ophthalmic branch of the trigeminal nerve, resulting in decreased corneal sensation.
**Why Each Wrong Option is Incorrect**
**Option A:** Not provided, unable to comment.
**Option B:** Not provided, unable to comment.
**Option C:** Not provided, unable to comment.
**Option D:** Not provided, unable to comment.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that decreased corneal sensation can increase the risk of **corneal ulcers** and other ocular complications. It is essential to evaluate and manage conditions that affect corneal sensation promptly.
**Correct Answer:** D. Herpes Zoster