Pathology
Tissue Damage
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Get access- Ischaemia/infarction
- Trauma
- Zonular rupture: lens dislocation
- Ciliary muscle disinsertion: TM collapse and angle recession glaucoma
- Temperature extremes
- Light exposure
- Corneal epithelium damage in snow blindness
- Photoreceptor bombardment with photons
- Lasers
- Argon (green wavelengths)
- YAG/Nd (1064nm)
- Excimer CW (193nm)
- Acid burns: coagulate proteins which prevents deep tissue penetration
- Epithelial and stromal necrosis leads to reactive fibrosis: entropion/ectropion
- Corneal scarring
- Alkali burns: penetrate tissues easily
Hot Topic
Alkali injury
The corneal epithelium is not an effective barrier against alkali penetration as it swells and desquamates
Alkali coagulates conjunctival blood vessels: “porcelain white” appearance
- Widespread limbal ischaemia and destruction of limbal stem cells
Collagenase release from the corneal epithelium leads to corneal and conjunctival necrosis
- Penetrates easily into cornea, stroma and aqueous
- Kills lens epithelium and causes non-granulomatous iridocyclitis