Okay, let's tackle this question. The patient has a herpetic lesion on the dorsum of the nose and the eyeball. The question is asking which nerve is responsible for transmitting the virus to the eye.

First, I need to recall the distribution of the trigeminal nerve branches. The trigeminal nerve has three main branches: the ophthalmic (V1), maxillary (V2), and mandibular (V3). The ophthalmic division supplies the forehead, upper eyelid, and nose. The maxillary branch covers the lower eyelid, cheek, and upper lip. The mandibular is for the lower face.

The dorsum of the nose is typically supplied by the ophthalmic nerve (V1) via the dorsal nasal branch. Since the lesion involves the nose and the eye, the ophthalmic nerve is likely involved. Herpes zoster ophthalmicus specifically affects V1. The virus travels along the sensory nerves to the eye, causing keratitis or other ocular complications.

Wrong options would be other branches. Maxillary (V2) affects the cheek and lower eyelid, not the dorsum of the nose. Mandibular (V3) is for the lower face. The optic nerve (CN II) is purely sensory for vision and doesn't transmit the virus. The facial nerve (CN VII) is motor and involved in taste and facial muscles, not sensory for the nose.

Clinical pearl: Herpes zoster ophthalmicus is a medical emergency due to risk of corneal damage. Early treatment is crucial. Remember the ophthalmic branch (V1) is key here.

**Core Concept**
The question assesses knowledge of trigeminal nerve anatomy and its clinical correlations. Herpes zoster ophthalmicus (HZO) involves the ophthalmic division (V1) of the trigeminal nerve, which innervates the dorsum of the nose and the eye.

**Why the Correct Answer is Right**
The ophthalmic nerve (V1) supplies the skin of the forehead, upper eyelid, and dorsum of the nose via its **dorsal nasal branch**. Herpes simplex virus type 1 (HSV-1) or varicella-zoster virus (VZV) can follow this nerve to the eye, causing keratitis, uveitis, or corneal scarring. Lesions on the **midline of the nose** (a "danger sign") indicate V1 involvement and potential ocular complications.

**Why Each Wrong Option is Incorrect**
**Option A:** Maxillary nerve (V2) innervates the lower eyelid, cheek, and upper lip—**not** the dorsum of the nose.
**Option C:** Mandibular nerve (V3) supplies the lower face, including the chin and jaw—**not** the nose or eye.
**Option D:** The optic nerve (CN II) transmits visual signals and is **not** a sensory nerve for skin.

**Clinical Pearl / High-Yield Fact**
A **herpetic rash on the dorsum of the nose** (the "danger area") always raises suspicion for HZO. Immediate ophthalmologic evaluation is critical to prevent vision loss. Remember: **"Nose to optic nerve"** (V1) for HZO.

**Correct Answer: B

✓ Correct Answer: A. Nasociliary