**Core Concept**
The early ocular sign of herpes zoster is related to the reactivation of varicella-zoster virus in the trigeminal nerve ganglion, leading to inflammation and damage to the ocular structures.

**Why the Correct Answer is Right**
The correct answer is a manifestation of viral replication and subsequent inflammation in the cornea, specifically involving the epithelial and stromal layers. The virus causes necrosis of the corneal epithelium and stroma, resulting in a characteristic appearance. This is due to the viral replication in the trigeminal ganglion and subsequent axonal transport to the eye.

**Why Each Wrong Option is Incorrect**
**Option A:** This is not a typical early sign of herpes zoster. Other options might be more accurate for herpes simplex.
**Option B:** This is not a primary ocular sign of herpes zoster. It is more commonly associated with herpes simplex.
**Option C:** This is an early sign of herpes zoster, but not the most characteristic one.

**Clinical Pearl / High-Yield Fact**
Herpes zoster ophthalmicus can cause severe ocular complications, including keratitis, uveitis, and vision loss. Early recognition and treatment are crucial to prevent these complications.

**Correct Answer: C. Dendritic ulcers are typically associated with herpes simplex keratitis, not herpes zoster.