A 32-year-old factory worker presents to the emergency department with acute chemical injury to the right eye after splash exposure to hydrochloric acid. After immediate copious irrigation with normal saline for 15 minutes, the cornea shows mild haziness and the anterior chamber is clear. Which is the drug of choice for immediate topical management to prevent progression of corneal scarring?

## Management of Chemical Eye Injuries ### Pathophysiology of Acid Burns Acid injuries cause immediate coagulation necrosis of corneal epithelium and stroma, with limited penetration due to protein precipitation. The primary goal of post-irrigation therapy is to prevent collagen remodelling and excessive scarring. ### Role of Ascorbic Acid (Vitamin C) **Key Point:** Topical ascorbic acid is the drug of choice for acute chemical eye injuries (both acid and alkali) to prevent corneal scarring and opacification. **Mechanism:** 1. Ascorbic acid is a cofactor for prolyl and lysyl hydroxylase enzymes 2. These enzymes cross-link collagen molecules 3. By inhibiting collagen synthesis and remodelling, ascorbic acid reduces scar formation 4. It also has antioxidant properties that reduce free radical damage ### Dosing and Administration - **Concentration:** 10% topical solution - **Frequency:** Every 30 minutes for the first 24 hours, then 4 times daily for 7 days - **Systemic supplement:** Oral ascorbic acid 500 mg 4 times daily also recommended ### Timeline of Chemical Injury Progression | Phase | Timeline | Pathology | Management Focus | |-------|----------|-----------|------------------| | Acute (0–7 days) | Immediate | Epithelial loss, stromal edema | Irrigation, ascorbic acid, antibiotics | | Early inflammatory (1–2 weeks) | Days 7–14 | Collagen remodelling begins | Ascorbic acid, anti-inflammatory agents | | Fibrotic (2 weeks–3 months) | Weeks 2–12 | Scar formation, neovascularization | Ascorbic acid, topical steroids, lubricants | | Late (>3 months) | Months 3+ | Mature scarring, symblepharon | Surgical intervention if needed | **High-Yield:** Ascorbic acid must be started **within 24 hours** of injury for maximum benefit; starting after 24 hours is less effective. ### Adjunctive Measures - Topical antibiotics (to prevent secondary infection) - Topical lubricants (preservative-free) - Topical corticosteroids (in early phase; controversial in alkali burns due to risk of perforation) - Cycloplegic agents (to reduce pain and photophobia) - Systemic ascorbic acid supplementation **Clinical Pearl:** In alkali burns (more severe than acid), ascorbic acid is equally important because alkali causes saponification of lipids and deeper penetration; the collagen-remodelling phase is more aggressive and prolonged. **Warning:** Do NOT delay ascorbic acid initiation waiting for investigations; clinical diagnosis and immediate treatment are paramount in chemical injuries.