**Core Concept**
Alkali burns of the eye are a serious ocular emergency caused by the penetration of alkali substances into the cornea and conjunctiva, leading to severe damage to the eye's surface and potentially causing vision loss. The severity of alkali burns is directly related to the pH of the substance and the duration of exposure.

**Why the Correct Answer is Right**
Alkali substances, such as caustic soda or lye, can cause severe damage to the eye by disrupting the corneal and conjunctival epithelium, leading to liquefactive necrosis. The high pH of these substances denatures proteins, disrupts cell membranes, and leads to the release of lysosomal enzymes, resulting in extensive tissue damage. The cornea is particularly vulnerable to alkali burns due to its thin epithelial layer and rich nerve supply, making it highly sensitive to pain and damage.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because acid burns, although severe, typically cause coagulative necrosis rather than liquefactive necrosis, resulting in a different type of tissue damage.
**Option B:** This option is incorrect because while certain chemicals can cause severe eye damage, they are not as potent as alkali substances in producing severe burns.
**Option C:** This option is incorrect because while radiation exposure can cause significant eye damage, it is not directly related to the type of chemical burns caused by alkali substances.

**Clinical Pearl / High-Yield Fact**
In cases of suspected alkali burns, it is essential to flush the eye with copious amounts of water for at least 15-20 minutes to minimize damage and prevent further injury.

**Correct Answer: C. Alkali substances.