**Core Concept**
Scleritis is a severe inflammatory eye disease characterized by inflammation of the sclera, the white outer layer of the eyeball. It can be associated with systemic autoimmune diseases, such as rheumatoid arthritis, and requires prompt medical attention to prevent vision loss.

**Why the Correct Answer is Right**
Scleritis typically presents with severe ocular pain, redness, and tenderness to touch. The inflammation can lead to thinning of the sclera, which may result in vision loss if left untreated. The condition often affects the posterior sclera, which is richly supplied with blood vessels and nerves, contributing to the severe pain experienced by patients.

**Why Each Wrong Option is Incorrect**
* **Option A:** Scleritis is typically unilateral, affecting one eye at a time, and is characterized by severe ocular pain and inflammation of the sclera.
* **Option B:** Scleritis is a type of anterior uveitis, but it specifically refers to inflammation of the sclera, whereas uveitis is a broader term that encompasses inflammation of the uveal tract, which includes the iris and choroid.
* **Option C:** Scleromalacia perforans is a rare condition that is often associated with systemic autoimmune diseases, characterized by thinning and perforation of the sclera, but it is not a type of scleritis.

**Clinical Pearl / High-Yield Fact**
Scleritis is often associated with systemic autoimmune diseases, such as rheumatoid arthritis, and requires a comprehensive evaluation to identify underlying conditions that may contribute to the development of the disease.

**Correct Answer: A. Scleritis is typically unilateral.**