**Core Concept**
Herpes ophthalmicus is a viral infection caused by the herpes simplex virus (HSV), primarily affecting the eye. It can lead to various ocular symptoms due to the reactivation of the latent virus in the trigeminal nerve ganglion. The infection can spread to the ocular structures, causing inflammation and damage.

**Why the Correct Answer is Right**
Oculomotor nerve involvement is not a typical symptom of herpes ophthalmicus. The trigeminal nerve, specifically the ophthalmic branch (V1), is primarily affected in herpes ophthalmicus. The oculomotor nerve (CN III) is responsible for eye movement and pupil constriction, and its involvement is more characteristic of other conditions such as diabetic ophthalmoplegia or stroke. The correct symptoms in herpes ophthalmicus include disciform keratitis, anterior uveitis, and nummular keratitis, which result from the viral infection and inflammation of the ocular tissues.

**Why Each Wrong Option is Incorrect**
**Option B:** Disciform keratitis is indeed a symptom of herpes ophthalmicus, characterized by a disc-shaped area of inflammation in the cornea. This occurs due to the viral infection and subsequent inflammatory response in the corneal stroma.
**Option C:** Anterior uveitis is also a symptom of herpes ophthalmicus, resulting from the viral infection and inflammation of the anterior segment of the eye, including the iris and ciliary body.
**Option D:** Nummular keratitis is another symptom of herpes ophthalmicus, characterized by small, coin-shaped areas of inflammation in the cornea.

**Clinical Pearl / High-Yield Fact**
Herpes ophthalmicus can lead to complications such as postherpetic neuralgia, a condition characterized by chronic pain in the affected area. This is more common in older adults and can be managed with pain medication and other supportive treatments.

**✓ Correct Answer: A. Oculomotor nerve involvement**