CHEMICAL EYE INJURIES

G. PAPANIKOLAOU

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

PATHOPHYSIOLOGY

ACID ALKALI

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)

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 10th day

• PMN: 12-24h and 14-21days

PATHOPHYSIOLOGY III

PHASES:

1. Immediate

2. Acute (0-7)

3. Early repair (7-21)

4. Late repair (>21)

GRADING

• Corneal clarity

• Limbal ischaemia

Grade Signs Prognosis

1 Clear/no excellent

2 Visible iris details/ <1/3

good

3 Hazy iris view/ 1/3<x<1/2

guarded

4 Opaque/ >1/2 poor

ACUTE MANAGEMENT

EMERGENCY !!!

AIMS

• Remove offending agent/ stop further damage

• Reduce inflammation

• Control IOP

• Reduce matrix degradation

• Promote reepithelization

MANAGEMENT I

• Irrigation

• Eversion of lids

• Debridement

• A/C Paracentesis

Grade I and II: steroid, antibiotic, cycloplegia for 1/52.

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

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

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

COMPLICATIONS

• Non-healing epith defect/ conjuctivalization/ melting (stem)

• Corneal opacities

• Cataract

• Glaucoma/ phthisis

• Dry eye

• Lid malposition/ symblepharon/ trichiasis: more scarring