**Core Concept**
Epidemic keratoconjunctivitis (EKC) is a highly contagious viral infection of the conjunctiva, caused by the adenovirus type 8 (Ad8). The infection leads to inflammation of the conjunctiva and cornea, resulting in symptoms such as redness, swelling, and vision impairment.

**Why the Correct Answer is Right**
EKC is characterized by a self-limiting course, typically resolving within 2-3 weeks. The infection is highly contagious and spreads through direct contact with an infected individual or contaminated surfaces. The adenovirus type 8 (Ad8) is the primary cause of EKC, which replicates in the conjunctival epithelial cells. The virus can also be shed in the tears, contributing to its contagious nature.

**Why Each Wrong Option is Incorrect**
**Option A:** EKC is not caused by a bacterial infection. It is a viral infection caused by adenovirus type 8.
**Option B:** EKC is not typically treated with antibiotics. The treatment primarily focuses on reducing symptoms and preventing complications.
**Option C:** EKC does not usually lead to permanent vision loss. However, it can cause temporary vision impairment and may lead to complications such as corneal ulcers.

**Clinical Pearl / High-Yield Fact**
The adenovirus type 8 (Ad8) is a highly contagious virus that can spread through direct contact with an infected individual or contaminated surfaces. It is essential to practice good hygiene, such as frequent handwashing and proper disinfection of surfaces, to prevent the spread of EKC.

**Correct Answer: C. EKC does not usually lead to permanent vision loss. However, it can cause temporary vision impairment and may lead to complications such as corneal ulcers.