Keratitis

Question 1

Define keratitis.

Answer 1

Inflammation of the cornea.

Microbial keratitis is not like conjunctivitis - it is potentially sight threatening and should therefore be urgently evaluated and treated. Non-microbial is rare.

Question 2

What are the causes of keratitis?

Answer 2

Bacterial - Staphylococcus aureus (most common) or Pseudomonas aeruginosa (contact lens wearers)
Fungal
Amoebic - acanthamoebic keratitis, accounts for 5% of cases; increased risk in soil or contaminated water exposure; pain out of proportion with clinical picture
Parasitic - onchocercal keratitis ‘river blindness’
Viral - HSV keratitis
Environmental - photokeratitis (e.g. welder’s arc eye), exposure keratitis, contact lens acute red eye (CLARE)
Autoimmune keratitis - RhA, SLE, PAN, GPA, Behcet’s, sarcoid, IBD, rosacea.

Question 3

What are some risk factors for keratitis?

Answer 3

• Poor lens hygiene or overnight lens wear
• Immunocompromised
• Autoimmune disease
• Blepharitis - chronic lid inflammation
• Dry eye
• Poor eyelid function

Question 4

What are the clinical features of keratitis?

Answer 4

• Red eye - pain and erythema
• Photophobia
• Foreign body, gritty sensation
• Hypopyon may be seen
• Opacification of transparent cornea
• Increased lacrimation
• Lid oedema
• Decreased visual acuity
• Photophobia

Question 5

What is shown?

Answer 5

Hypopyon

Question 6

How do you diagnose keratitis?

Answer 6

Difficult to assess as painful
Slit-lamp testing - DIAGNOSTIC, needs same day referral to an eye specialist to rule out microbial keratitis
Corneal scraping - ideally prior to starting antimicrobial therapy; for gram staining.

Question 7

What is the management of keratitis?

Answer 7

Stop contact lens use until symptoms fully resolved
Topical antibiotics - quinolones 1st line e.g. moxifloxacin ophthalmic 0.5% 1 drop every 1-6hrs for ~1 week
Cycloplegic - for pain relief by paralysing ciliary muscles thus dilating the eye e.g. atropine ophthalmic 1% 1-2drops QDS
Analgesia - paracetamol or ibuprofen

Question 8

What are the complications of keratitis?

Answer 8

Corneal scarring - use topical steroids to minimise risk of this
Perforation
Endophthalmitis - spread of infection to intraocular cavities
Visual loss
Glaucoma - may accompany active herpetic disease

Question 9

What is the management of herpes simplex keratitis?

Answer 9

Immediate referral to ophthalmologist - fluorescein staining will show an epithelial ulcer
Topical aciclovir

Question 10

What is the prognosis with keratosis?

Answer 10

Most have good prognosis and retain excellent vision

A fifth may have >2 Snellen lines of vision loss post-microbial keratitis