CHEMICAL EYE INJURIES

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CHEMICAL EYE INJURIES
G. PAPANIKOLAOU
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EPIDEMIOLOGY
2/3 at work, young, males Alkaliacid21 Alkali
NH3, NaOH, Ca(OH)2, KOH, MgOH2 Acid H2SO4, HF,
Acetic, HCl

• Damage depends on
• pH
• area
• Volume/duration
• Inherent toxicity

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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)

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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

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PATHOPHYSIOLOGY III

• PHASES
• Immediate
• Acute (0-7)
• Early repair (7-21)
• Late repair (gt21)

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GRADING

• Corneal clarity
• Limbal ischaemia

Grade Signs Prognosis
1 Clear/no excellent
2 Visible iris details/ lt1/3 good
3 Hazy iris view/ 1/3ltxlt1/2 guarded
4 Opaque/ gt1/2 poor
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ACUTE MANAGEMENT
EMERGENCY !!!

• AIMS
• Remove offending agent/ stop further damage
• Reduce inflammation
• Control IOP
• Reduce matrix degradation
• Promote reepithelization

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MANAGEMENT I

• Irrigation
• Eversion of lids
• Debridement
• A/C Paracentesis

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

• Recheck pH 5-10 min after irrigation
• White eye worse than red
• Complete epith defects or if only Bowmans delay
  in taking up FLN Repeat
• Avoid PHNL

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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

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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

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COMPLICATIONS

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

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