Which type of burn is more harmful to the cornea?

• A. Alkali
• B. Acid
• C. Both are equally harmful
• D. Neither is harmful

Answer: (A)

Alkali burns are more harmful to the cornea because they penetrate rapidly and cause ongoing tissue destruction. The alkali saponifies fats in cell membranes and denatures proteins, leading to liquefactive necrosis. This process allows the chemical to dive deeper into the cornea, reaching the stroma and even the limbal area, where stem cells reside. The result can be extensive epithelial loss, stromal damage, limbal stem cell deficiency, and a higher risk of thinning or perforation.

In contrast, acids tend to cause coagulative protein coagulation on the surface, which forms a barrier and tends to limit how deeply the injury goes. That means corneal surface damage can be significant, but deep penetration into the stroma is usually less extensive than with alkali burns.

Because of this difference, alkali exposures require especially prompt and thorough irrigation and urgent ophthalmology evaluation to limit deeper injury and preserve corneal structure and vision.