**Core Concept**
The question is testing the knowledge of the ocular manifestations of diphtheria, a bacterial infection caused by Corynebacterium diphtheriae. The correct answer is related to the toxin-mediated effects of diphtheria on the eye.

**Why the Correct Answer is Right**
Diphtheria toxin causes damage to the corneal epithelium and subepithelial tissue, leading to a characteristic condition known as diphtheric keratoconjunctivitis. This condition is characterized by a thick, grey membrane that forms on the cornea, leading to vision loss if left untreated. The toxin inhibits protein synthesis by inactivating elongation factor-2 (EF-2), which is essential for the translation of messenger RNA into proteins.

**Why Each Wrong Option is Incorrect**
* **Option A:** While diphtheria can cause paralysis, it is not the most common ophthalmic effect.
* **Option B:** Diphtheria does not typically cause uveitis.
* **Option C:** Diphtheria is not commonly associated with cataract formation.

**Clinical Pearl / High-Yield Fact**
Diphtheric keratoconjunctivitis is a medical emergency that requires prompt treatment with antibiotics and supportive care to prevent vision loss.

**Correct Answer:** C. Diphtheric keratoconjunctivitis.