Keratitis

• also known as a corneal ulcer, is an inflammation or irritation of the cornea
• Risk factors
  • contact lens (hypoxia, hygiene)
  • corneal trauma
  • corneal surgery
  • post-herpetic corneal lesion
  • dry eye
  • corneal anaesthetic
  • corneal exposure (e.g. VII lesion)
  • ocular surface disease (herpetic, chornic blepharitis, dry eyes)
  • immunosuppression

Types

• bacterial
  •     streptococcus pneumoniae
  •     pseudomonas aeruginosa (commonly seen in contact lens users)
  •     klebsiella
• fungal

• andida albicans 
• Aspergillus fumigatus 

• fusarium sp
• viral / dendritic
  • HSV – dendratic ulcers
  • Adenovirus
  • VZV
• Protozoal
  • Acanthamoeba
• marginal
• secondary to chronic blepharitis, ocular hypersensitivity reaction to conjunctival infection with Staphylococcus aureus. Also associated with Ocular rosacea
• presents with
  • conjunctivitis – which may be mild
  • photophobia
  • pain
  • limbal congestion
• non infectious
  • Local causes
    • includes  trichiasis
    • giant papillae
    • foreign body in sulcus subtarsalis Injury to the cornea, such as a scratch
    • Dryness or inflammation of the cornea
    • Overexposure to ultraviolet light
  • Allergies
  • contact lens wear

Common symptoms:

• more discomfort than conjunctivitis
• Pain increases with time (vs abrasion which resolves 24 – 48hrs)
• red eye
• Discomfort, foreign body sensation, eyelid swelling and lacrimation
• If progresses 🡪 severe pain, photophobia, eye discharge, decreased VA 
• Acanthomboea
  •  pain out of proportion

examination

• Corneal infiltrate or defect
• keratitis may be identified by a white/grey patch on the cornea
  • represents a collection of white blood cells in the corneal tissue
  • fluorescein drops aid in diagnosis: lesions of the cornea stain green
  • Herpetic often less painful than size of lesion
• hypopyon
  • may be inflammatory reaction of spread into eye
• Protrusion of iris
  • perforation of cornea
• Irregularity of pupils
  • posterior synechiae due to anterior uveitis
• Elevated intraocular pressue if trabecular meshwork is blocked
• Can be bacterial, fungal, viral, acanthomoeba

Adenoviral Keratoconjunctivitis 

• highly contagious
• usually unilateral to start with; however, it becomes bilateral later.
• Conjunctival inflammation can progress to focal epithelial keratitis, and the resulting lesions can last for up to2 weeks.
•  After this period, subepithelial infiltrates (also known as “nummuli”), which are thought to be related to the immune response, can form beneath the lesions. 
• These occur at approximately day 10 and can give rise to irregular astigmatismand photophobia. 
• These symptoms and decreased visual acuity can persist for months or years
• In about 25% of cases patients can develop severe findings, including
  • membranous or pseudomembranous conjunctivitis
  • manifesting as punctate corneal erosions
  • causing scarring of the conjunctiva and symblepharon formation
  • wherein the eyelid adheres to the cornea
• Ocular signs/symptoms
  • Conjunctival hyperemia/erythema (redness) of bulbar conjunctiva
  • Conjunctival hyperemia/erythema (redness) of palpebral conjunctiva 
  • Ocular itchiness and irritation
  • Chemosis (conjunctival edema)
  • Photophobia
  • Epiphora (excessive tearing)
  • Foreign body sensation
  • Blurred vision/loss of visual acuity
  • Eyelid swelling
  • Follicular reaction
  • Clear or yellow discharge from the eye
  • Epithelial keratitis
  • Dacrocystitis
• Systemic findings
  • Preauricular lymphadenopathy
  • Pharyngitis
  • Fever

.

Herpes simplex keratitis:

• Herpes simplex virus (HSV) is a very common
• lifelong infection that often is asymptomatic. However, HSV can result in significant eye disease.
• unilateral or, more rarely, bilateral. 
• Characteristically
  • classic dendritic lesions with terminal bulbs  
  • vesicular lesions on the lids or adnexa
  • bulbar follicles
  • decreased corneal sensation,
  • enlarged preauricular lymph node
  • Recurrent activations within the sensory ganglion can result in:
    • cornea scarring
    • necrosis
    • decreased corneal sensation (neurotrophic cornea)

all of which can be vision threatening.

• Risk Factors
  • Risk factors for development of primary HSV involve direct contact with infected secretions or lesions.
  • Sunlight/Fever/Trauma/Heat/Stress/Trigeminal nerve manipulation/Infectious disease and immunocompromised states.
• Primary HSV epithelial keratitis usually resolves spontaneously; however, treatment with antiviral medication does indeed shorten the course of the disease and may therefore reduce the long- term complications of HSV
• Long term complications:
  • Corneas with decreased sensation due to corneal nerve changes after infection
  • Severe dry eyes
  • Corneal perforation
  • Non- healing neurotrophic ulcer.
• Prognosis is usually good, but greatly varies depending on severity and number of recurrences of the disease..

Management

Contact lens wearers 

• Immediate referral for consideration of a corneal scrape for microbiological testing and initiation of topical treatment
• Bacterial
  • ciprofloxacin 0.3% eye drops, 1 drop into the affected eye, every hour (including overnight)       

OR

• ofloxacin 0.3% eye drops, 1 drop into the affected eye, every hour (including overnight)   

OR (if available)

• cefazolin 5% plus gentamicin 0.9% eye drops, 1 drop into the affected eye every hour (including overnight)

dendritic ulcer

• Aciclovir 3% eye ointment topically into the affected eye, 5 times daily for 10 to 14 days, or for at least 3 days after healing, whichever is shorter.
  • If the eye ointment is not available, use oral antiviral therapy.
    • Valaciclovir 500 mg orally, 12-hourly for 7 to 10 days       

OR

• Aciclovir 400 mg orally, 5 times daily for 7 to 10 days. 
• Inappropriate and indiscriminate use of topical steroids may result in geographical ulcer formation
• Penetrating keratoplasty
  • If there is visually significant stromal scarring

Herpes zoster ophthalmicus

• Start treatment as soon as the diagnosis is suspected, ideally within 72hrs
• oral antiviral therapy for immunocompetent patients. 
• Intravenous aciclovir for immunocompromised patients 
• Topical aciclovir has no role in the initial treatment of herpes zoster ophthalmicus.
  • Valaciclovir 1 g (child over 2 years: 20 mg/kg up to 1 g) orally, 8-hourly for 7 days       

OR

• Famciclovir 500 mg orally, 8-hourly for 7 days       

OR

• Aciclovir 800 mg (child: 20 mg/kg up to 800 mg) orally, 5 times daily for 7 days. 

Adenovirus keratoconjunctivitis

• Epidemic keratoconjunctivitis resolves on its own and there is no effective treatment. 
• Antiviral medications have not been shown to be effective against viral conjunctivitis
• Topical corticosteroids are often prescribed in severe cases and while they do assist in reducing inflammatory symptoms, they do not significantly reduce recovery time.
  • Some studies have in fact shown that the use of corticosteroids may in fact increase the duration of disease by inhibiting removal of the adenovirus by the immune system and improving the replication of the virus
• Methods for symptom reduction include:
  • cold compresses
  • artificial tears
  • cycloplegic medications 
• Povidone-iodine is a disinfectant and antiseptic agent that could potentially offer an effective treatment.

UV keratitis (welders Keratitis)

• Flash burn UV – band like 
• 6-12 hours after exposure
• Oral analgesics
• Topical anaesthetics
• Don’t give topical anaesthetic