Cornea I : Microbial Keratitis

What are the causes of Bacterial/Fungal Keratitis ?

> common bacterial pathogens :

Pseudomonas sp. (Gram -ve)

Staphylococcus sp.( Gram +ve)

Streptococcus sp.(Grame +ve)

> Fungal Keratitis (rare)

Candida sp

Fusarium

Aspergilus

What are the Predisposing factors of Bacterial/Fungal keratitis?

• Ocular surface disease

• Lid margin infection

• Ocular trauma or surgery

• CL wear → extended + poor case hygiene

• Topical steroids

• Neurotrophic keratopathy → 2nd to HSV or diabetes

• Immune compromise

What are the symptoms of Bacterial/Fungal Keratitis ?

• PAIN → moderate to severe

• usually acute onset

• Redness

• Discharge

• Photophobia

• Blurred vision

• awareness of white spot on cornea

What are the signs of Bacterial/Fungal keratitis ?

• Epiphora

• Discharge → mucopurulent ot purulent

• Conjunctival hyperaemia

• corneal lesion → single (central or mid-peripheral)

• ulcer

• stromal infiltration &oedema → folds in descemets membrane

• Hypopyon

• Flare and cells in anterior chamber

What is the optometric management of Bacterial/Fungal keratitis?

• SAME DAY REFERRAL TO EYE CLINIC

• sight threatening condition

• STOP CL WEAR

• Take CL and case to clinic for culture

What tx are given for microbial/fungal keratitis?

• Antibiotics for bacterial infections → levofloxacin, moxifloxacin

Hospital admission → severe infections , cycloplegia , topical steroids once infection controlled

Fungal infections → combined topical and oral therapy e.g natamycin (5%)

oral voriconazole

What are the causes of viral Keratitis?

• Herpes simplex virus

• Herpes Zoster

• Adenovirus

What are the predisposing factors to Viral keratitis?

• poor general health → immunodeficiency

• Streoids , immunosuppressants

• Previous ocular HSV

• HZO

• Adenovirus , Upper respiratory tract infection

What are the symptoms of Viral Keratitis?

• Redness

• Watery

• Mild-moderate burning

• variable levels of pain

• Photophobia

• Blurred vision

What are the signs of Viral Keratitis ?

• Conjucntival Hyperaemia

• Epiphora/water discharge

• ulcer

• keratitis

What is the optometric management of Viral Keratitis?

• SAME DAY EMERGENCY REFERRAL → sight-threatening conditon

Herpes Simplex keratitis signs and symptoms

• usually unilateral

• Irritation-pain

early signs → coarse punctate or stellate pattern

Later signs →dendritic ulcer

reduced corneal sensitivity

recurring

Heals in 1-2 weeks with scarring

geographic ulcer can follow → topical steroids

What is the optometric management of HSK?

• Stromal involvement → same day referral

• No stromal involvement → URGENT REFERRAL within one week to ophthalmologist

• DILATE to exclude viral retinitis

what would be management by the ophthalmologist

• Antivirals → Topical systemic (Acyclovir 5x daily for a week)

• Topical steroid after tx

• Swab or biopsy

What are the general symptoms of Herpes Zoster Opthalmicus ?

• pain and altered sensation of one side of forehead

• Vesicular rash affecting forehead/upper eyelid

• General malaise , headache, fever

What are the Ocular symptoms of HZO?

• Discomfort

• Warery/sticky discharge

• Redness

• Pain

• Photophobia

• ±blurring

What are the skin signs of HZO?

• Unilateral pain, vesicular rash

• crusts in 2-3 weeks

• Hutchingsons sign

• keratic precipitates

Ocular signs of HZO

• mucopurulent conjucntivitis

• Keratitis → disci form pseudo dendrites

• reduced corneal sensation

• keratic precipitates

• complications can occur months or yrs after acute phase

What is the management of Herpes Zoster Opthalmicus ?

• URGENT referral

• systemic ant-viral tx (<72hrs)

• Corneal involvement , anterior uveitis or elevated IOP

• Rest → support at home

• Risk of infecting others with chickenpox

• Topical lubricants for symptomatic relief

• pain relief → paracetamol

What are the signs of Adenovirus?

• Punctate epithelial keratitis

• Follicular conjunctivitis → upper and lower eyelids

What is the management of Adenovirus

• Typically self-limiting

• if significant keratitis (pain and/or vision loss)→ EMERGENCY referral

• Hygiene → don’t share towels

What are the predisposing factors of Protozoal (Acanthamoeba) Keratitis ?

• Soft CL → extended wear

• Poor CL hygiene

• Contacts with water→ showering , swimming , hot tubs

rare but more common in CL wearers

What are the symptoms of Acanthoemeba keratitis?

• Pain

• Redness

• Watering

• Photophobia

• Loss of vision

• May be bilateral

What are the signs of Acanthomeoba Keratitis ?

Early signs

• pseudo dendrites

• Radial keratoneuritis → infiltrates along corneal nerves

Later signs :

• central ring-shaped infiltrate

• stromal thinning

• AC activity → flare and cells, hypopyon

• scleirits

Management of Acanthomeoba Keratitis

• EMERGENCY referral

• Stop all CL wear

• Advise px to take their CL and case with them

Secondary care of Acnathomeobe keratitis

• Anti-oembic drug

• Polyhexamethyl biguinade (PHMB)

• lots of eye drops

• antibiotics for secondary infection