A chemical injury to the eye with alkali (lime) is considered more dangerous than acid injury because:

• A Acids denature proteins forming an eschar that limits penetration
• B Alkali has a lower pH than acids at comparable concentration
• C Alkali causes liquefactive necrosis and saponification of fatty acids, allowing deep and continued penetration into the anterior chamber ✓
• D Acids are buffered by the tear film, reducing damage

Explanation

Alkali burns (lime, lye, ammonia) are more severe because alkalis dissolve cell membranes through saponification of membrane lipids and cause liquefactive necrosis, which lacks the self-limiting protective protein precipitation (coagulative necrosis/eschar) that forms with acid burns. The absence of an eschar means alkali continues to penetrate through the cornea into the anterior chamber, damaging the trabecular meshwork, ciliary body, iris, and lens. Immediate and copious irrigation (at least 30 minutes) is the priority, followed by pH testing to confirm neutralisation.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.