Corneal abrasion and corneal foreign body

Question 1

What is a corneal abrasion?

Answer 1

A defect in the epithelial surface of the cornea caused by trauma

Question 2

Describe the pathophysiology of corneal abrasion.

Answer 2

Corneal abrasions happen when there is a epithelial disruption due to direct trauma to the cornea leading to loss of cells and a break in the protective layer.

Question 3

List the 3 classifications of corneal abrasion.

Answer 3

1. Traumatic: Mechanical trauma from an external object e.g. fingernails scratch among children and contact lens during insertion or removal.
2. Foreign body related
3. Spontaneous: Underlying condition or injuries e.g. recurrent corneal erosion syndrome, underlying medical condition, trichiasis, UV or chemical keratitis.

Question 4

Give 4 risk factors for corneal abrasion.

Answer 4

• Occupation
• Dry or weak cornea
• Contact lens- extended wear, poor hygiene, ill fitting lens
• Bell’s palsy
• Eyelid surgery
• Investigative instrumentation: tonometer

Question 5

How does corneal abrasion present? (5)

Answer 5

• Red eye – due to inflammation and irritation of the eye
• Eye pain
• Excessive squinting
• Foreign body sensation
• Photophobia
• Epiphora
• Decreased visual acuity
• Blurred vision

Question 6

Give 5 differentials for corneal abrasion.

Answer 6

• Conjunctivitis
• Keratoconjunctivitis sicca
• Subconjunctival hemorrhage
• Infectious keratitis (bacterial, fungal, herpetic)
• Acute angle closure glaucoma
• Corneal foreign body
• Uveitis
• Trichiasis
• Recurrent erosion syndrome
• Limbal stem cell deficiency

Question 7

How is corneal abrasion?

Answer 7

Supportive care
Most corneal abrasions heals spontaneously within 24 - 48 hours
Lubricating eye drops (artificial tears) can help relieve discomfort
Cycloplegic drops: cyclopentolate

Pain management
Topical analgesic e.g. proparacaine drops
Oral analgesic acetaminophen or ibuprofen for severe pain

Antibiotics
Topical antibiotics: erythromycin ointment
If contact lens; antibiotic against pseudomonas spp.; fluoroquilones

Tetanus vaccine if not fully vaccinated

Question 8

Give 2 complications of corneal abrasion.

Answer 8

1. Microbial keratitis
2. Recurrent erosion syndrome
3. Infected corneal ulceration

Question 9

Mention 7 signs and symptoms of CFB.

Answer 9

Symptoms
Foreign body sensation
Excessive tearing
Pain
Light sensitivity
Decreased vision
Continued irritation

Signs
Redness
Visible foreign objects
Corneal rust from a metal object
Fluorescent stain around foreign material
Subconjunctival hemorrhage may occur

Question 9

What is a corneal foreign body?

Answer 9

Any external object embedded on or within corneal surface disturbing its normal structure and function.

Question 10

Give 2 risk factors for corneal foreign body (CFB).

Answer 10

Occupation - metal working, construction, grinding and welding

Lack of eye protection in risky scenarios e.g. stormy conditions

Road traffic accidents

Question 11

How can CFB be managed?

Answer 11

Removal under slit lamp visualization

Loose FB can be irrigated away with normal saline

Topical antibiotics after removal

Topical cycloplegics

No corticosteroids –foster bacterial and fungal growth

Question 12

Give 4 differentials for CFB.

Answer 12

Corneal abrasion

Keratitis

Conjunctival foreign body

Recurrent corneal erosion syndrome

Globe perforation

Intraocular foreign body

Question 13

List 3 complications of CFB.

Answer 13

• Corneal abrasion
• Infections - Infectious keratitis
• Rust ring formation