**Core Concept**
Herpes simplex keratitis is a common ocular surface disorder caused by the reactivation of herpes simplex virus (HSV) on the cornea. It is characterized by the formation of dendritic ulcers, which can lead to vision loss if left untreated.

**Why the Correct Answer is Right**
Herpes simplex keratitis is often associated with the formation of dendritic ulcers, which are a hallmark of the disease. The virus infects the corneal epithelium, causing a characteristic branching or "dendritic" pattern of ulceration. This is due to the virus's ability to infect and replicate in the corneal epithelial cells, leading to cell death and the formation of ulcers. The correct answer is related to the pathophysiology of herpes simplex keratitis.

**Why Each Wrong Option is Incorrect**
**Option A:** Corneal edema is a possible complication of herpes simplex keratitis, but it is not the hallmark of the disease. Corneal edema can occur due to the inflammation and cell death caused by the virus.

**Option B:** The formation of dendritic ulcers is a key feature of herpes simplex keratitis, making this option incorrect.

**Option C:** Herpes simplex keratitis can cause vision loss if left untreated, but this is a potential complication rather than a distinguishing feature of the disease.

**Option D:** This option is correct. Other forms of herpetic keratitis include stromal keratitis and iridocyclitis, but dendritic ulcers are not a characteristic feature of these conditions.

**Clinical Pearl / High-Yield Fact**
Dendritic ulcers are a classic sign of herpes simplex keratitis, and their presence should prompt a high level of suspicion for this condition.

**Correct Answer: D. Dendritic ulcers are not a characteristic feature of other forms of herpetic keratitis.**