Cornea: Trauma & Industrial Injury

Question 1

What are the 6 layers of the cornea?

Answer 1

• Epithelium
• Basement membrane
• Bowman’s layer
• Stroma
• Descemet’s membrane
• Endothelium

Question 2

Describe the epithelium and the endothelium?

Answer 2

Epithelium –> outer layer, barrier, continuously regenerates

Endothelium –> inner layer, cornea remains its clarity by endothelium acting as a pump to keep the stroma hydrated to right level – keeps cornea clear – only born with certain number of endothelium cells (do not regenerate) so if they become dysfunctional/damaged the cornea can become hazy – hard to treat

Question 3

What are the questions to ask (yourself & px) if px presents with trauma or industrial injury?

Answer 3

• What type of object caused the trauma?
  o Organic?
  o Non-organic?
  o Metal?
  o Plastic?
• What velocity was object travelling at?
• What size was the object?
• What is something sharp, likely to penetrate eye, or was it something that would cause blunt trauma?
• More than one object?
• Multiple small fragments? – risk of something stuck under lids
• What direction was object travelling in?

Question 4

Describe a corneal abrasion?

Answer 4

• Trauma just enough to take off the corneal epithelium, exposes nerves under it & is v painful but does remain superficial
• Absence of endothelium and NaFl pools where there is epithelial defect

Question 5

Describe recurrent corneal erosion?

Answer 5

• Presents with similar appearances as corneal abrasion.
• Stains with NaFl.
• Condition that occurs due to weakness in the hemidesmosome.
• Epithelium is loosely connected to underlying stroma & can peel away like wallpaper.
• Often no major trauma associated.
• Pxs say it happens first thing in morning when wake up – some pxs eyelids don’t completely close at night, eyes dry out, if lids stick to ocular surface then when open eyes it takes the epithelium with it leading to large abrasion.
• Small scratch can also lead to an abrasion

Question 6

Describe hyphaema?

Answer 6

• Blood in anterior chamber
• Measure height of blood level – use slit lamp – DOCUMENT HEIGHT & SIZE to appropriately monitor improvement
• High risk of raised IOP – blood can clog trab meshwork
• Should resolve over next few days to weeks

Question 7

Describe a penetrating eye injury?

Answer 7

• Integrity of globe is compromised
• For iris defect to have occurred, an object must have penetrated the cornea – px essentially has open globe – FB may be lodged in retina
• May not be v obvious if small, sharp object has caused it
• When assessing for open globe:
  o IOP is likely to be low
  o Anterior Chamber may be completely flat or shallow compared to other eye – examine both eyes
  o If sclera or corneal defect, iris may be drawn up to defect – may have irregular pupil
• V small injuries can be treated with CL or corneal glue - vast majority of time when px presents then they need to be taken to theatre for suturing