1. CHEMICAL EYE INJURIES G. PAPANIKOLAOU

2. EPIDEMIOLOGY 2/3 at work, young, males Alkali:acid=2:1 Alkali: NH3, NaOH, Ca(OH)2, KOH, MgOH2 Acid: H2SO4, HF, Acetic, HCl Damage depends on: pH area Volume/duration Inherent toxicity

3. PATHOPHYSIOLOGY ACIDALKALI Denaturation+ precipitation of proteins on contact/ ‘ground glass appearance’ Barrier to penetration Damage to stromal matrix secondary to inflammation Saponification of fatty acids in cell membranes Rapid penetration Damage to deeper structures Direct effect Indirect effect (inflammation)

4. PATHOPHYSIOLOGY II POINTS IN CORNEAL HEALING: Epithelium regulates keratocytes, prevents sterile ulceration TGF-beta 2: inhibits collagenase synthesis by keratocytes Limbal vessels: provide collagenase inhibitors Stem cells: centripetal healing ‘Transdifferentiation’/ ‘conjuctivalization’ Stroma: type I collagen (keratocytes) Steroids intervene with keratocyte migration/ synthesis Ascorbate co- factor in collagen synthesis MMPs: increase after 10 th day PMN: 12-24h and 14-21days

5. PATHOPHYSIOLOGY III PHASES: 1.Immediate 2.Acute (0-7) 3.Early repair (7-21) 4. Late repair (>21)

6. GRADING Corneal clarity Limbal ischaemia GradeSignsPrognosis 1Clear/noexcellent 2Visible iris details/ <1/3 good 3Hazy iris view/ 1/3<x<1/2 guarded 4Opaque/ >1/2poor

10. ACUTE MANAGEMENT EMERGENCY !!! AIMS Remove offending agent/ stop further damage Reduce inflammation Control IOP Reduce matrix degradation Promote reepithelization

11. MANAGEMENT I Irrigation Eversion of lids Debridement A/C Paracentesis Grade I and II: steroid, antibiotic, cycloplegia for 1/52.

12. TIPS Recheck pH 5-10 min after irrigation White eye worse than red Complete epith defects or if only Bowman’s delay in taking up FLN: Repeat Avoid PHNL

13. MANAGEMENT II Steroids/ up to10/7, NSAIDS Antibiotics Vit-C/ early Citric acid/ Ca chelation/ early Tetracyclines/ chelate zinc Acetylcysteine/ MMP Artificial tears BCL Tarsoraphy IOP control

14. MANAGEMENT III Tenoplasty/ early in grade IV (limb. Vascularity) Stem cell transplant (auto/allo)/ early or late Amniotic membrane graft Conjuctival/ mucosal grafts Correct lid malposition Fornix reconstruction Dry eye Glaucoma, Cataract Cyanoacrylate glue, tectonic PTK PTK (large), Keratoprosthesis

15. COMPLICATIONS Non-healing epith defect/ conjuctivalization/ melting (stem) Corneal opacities Cataract Glaucoma/ phthisis Dry eye Lid malposition/ symblepharon/ trichiasis: more scarring