Keratitis

Question 1

Define keratitis

Answer 1

Infection of the cornea, which is a common yet sight-threatening ophthalmic emergency

Question 2

Aetiology of keratitis

Answer 2

Bacterial: Staph aureus, Pseudomonas (contact lens use)
Viral: herpes simplex (reactivation of HSV1 in the trigeminal ganglion)
Amoebic: exposure to soil/contaminated water
Parasitic: onchocercal (river blindness)
Photokeratitis (Welder’s arc eye)
Exposure keratitis

Question 3

Risk factors for keratitis

Answer 3

Bacterial:
- Minor trauma to the cornea
- Contact lens use
- Ocular surgery
- Disease affecting the conjunctiva or cornea
- Immunocompromise

Question 4

Symptoms and signs of keratitis

Answer 4

Pain
Foreign body sensation
Tearing or purulent discharge
Red eye
Photophobia

Corneal ulcer (seen on fluorescein staining)
Hypopyon

Question 5

Investigations for keratitis

Answer 5

Slit-lamp examination + fluorescein staining: ulceration
Corneal scrape culture
Contact lens/solution culture

Confocal microscopy/US biomicroscopy

Question 6

Management for keratitis

Answer 6

Immediate ophthalmology evaluation
- In severe infections, hospital admission may be required for close monitoring and treatment.
Immediate cessation of contact lens use
Bacterial → Intensive topical quinolone ± PO abx
Herpes simplex → topical acyclovir
Pain relief: cyclopentolate

Question 7

Complications of keratitis

Answer 7

corneal scarring
perforation
endophthalmitis
visual loss