**Core Concept**
Neovascular glaucoma is a complication of ischemic or diabetic retinopathy characterized by the formation of new, fragile blood vessels on the iris and trabecular meshwork. This process leads to increased intraocular pressure (IOP) due to impaired aqueous humor outflow.

**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of neovascular glaucoma. The formation of new blood vessels on the iris and trabecular meshwork leads to a reduction in aqueous outflow, resulting in increased IOP. The classical sign of neovascular glaucoma is rubeosis iridis, which is the presence of new, fragile blood vessels on the iris. This is a critical sign that indicates the development of neovascular glaucoma.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the classical sign of neovascular glaucoma. The correct answer is related to the presence of new blood vessels on the iris, not the cornea.
* **Option B:** This option is incorrect as it describes a sign of acute angle-closure glaucoma, not neovascular glaucoma. The correct answer is related to the presence of new blood vessels on the iris, not a sudden blockage of the trabecular meshwork.
* **Option C:** This option is incorrect as it describes a sign of uveitis, not neovascular glaucoma. The correct answer is related to the presence of new blood vessels on the iris, not inflammation of the uvea.

**Clinical Pearl / High-Yield Fact**
A key clinical pearl to remember is that rubeosis iridis is a critical sign of neovascular glaucoma, and its presence indicates the need for urgent medical attention to prevent vision loss.

**Correct Answer:** C.