Corneal Abrasion and Ulceration

Question 1

Define Corneal Abrasion and Ulceration

Answer 1

Corneal abrasion is the term often applied to any defect in the corneal surface epithelium. These abrasions can most commonly be classified as trauma (due to mechanical insults of fingernails, paws etc), foreign body, contact lens and spontaneous. The abrasion may be associated with an ulcer.

Question 2

Causes of Corneal Abrasion and Ulceration

Answer 2

Trauma
Contact lens wear/injury
Infection (aka microbial keratitis)
-> Bacterial (pseudomonas [contact lens])
-> Viral (herpes simplex [dendritic ulcer] or herpes zoster ophthalmicus)
-> Fungal
-> Protozoa
Neurotopic
Immune related (rheumatoid arthritis)
Spontaneous

Question 3

Clinical Presentation of Corneal Abrasion and Ulceration

Answer 3

Excruciating eye pain
Objective evidence of foreign body sensation

Other symptoms include

• Epiphoria (watering of the eye)
• Blepharospasm (involuntary tight closure of the eyelids)
• Blurred vision.

Question 4

Examination of Corneal Abrasion and Ulceration

Answer 4

Examine extent of trauma

• Fluorescein stain and invert upper lid
• Check that the anterior chamber appears grossly clear, deep and of normal contour

Acuity

Local anaesthetic test
- Superficial corneal problems (such as corneal ulcer, foreign body) will be relieved by a single drop of local anaesthetic. Deeper pain may be due to uveitis.

Question 5

Management of Corneal Abrasion and Ulceration

Answer 5

• Check record for visual acuity
• Check for and remove foreign body
• Pain relief
  
  • Local anaesthetic eye drops for initial examination only
  • Cycloplegic drops causing paralysis of ciliary muscle
• Prophylaxic antibiotic chloramphenicol eye ointment
• Consult ophthalmologist if pain with contact lenses
• A folded padded eye pad may be applied (not for cleanliness, but to keep the lid lowered over the defect)

Foreign body removal is required to prevent rust formation and chemical and/or microbial keratitis around the foreign body.

Question 6

Define Microbial Keratitis and Common Types

Answer 6

Keratitis is corneal infection and inflammation. Commonly due to viral or bacterial causes including:

• Herpes simplex keratitis
• Herpes zoster ophthalmicus
• Bacterial keratitis

Question 7

Herpes Simplex Keratitis Overview

Answer 7

• HSV 1 is a major worldwide cause of blindness due to corneal scarring and opacity.
• Can be asymptomatic or with fever, vesicular lid lesion, follicular conjunctivitis and pre-auricular lymphadenopathy
• Treatment with acyclovir and on occasions debridement of ulcer

Question 8

Herpes Zoster Ophthalmicus Overview

Answer 8

• AKA ophthalmic shingles
• Varicella zoster virus infestation of the ophthalmic division of the trigeminal nerve occurs with a prodromal period of being systemically unwell.
• Presents with lid swelling (can be bilateral), keratitis, iritis, secondary glaucoma.
• Treatment with acyclovir

Question 9

Bacterial Keratitis Overview

Answer 9

• Common causes include:
  -> staph aureus
  -> Pseudomonas aeruginosa
  -> Strep pneumonia
  Common causes:
  -> contact lens
  -> trauma
  -> steroid use
  Clinical Presentation
  -> Hazy cornea, hypopyon (mass of white cells in anterior chamber) and markedly inflamed conjunctiva
• Management
  -> Gram stain and culture
  -> Cefuroxime (G+) and gentamicin (G-)