Fungal corneal ulcer

By Glin Luckose Fernandez

The incidence of fungal corneal ulcer has increased during the recent years due to injudicious use of antibiotics and steroids

Contents • Etiology• Modes of infection • Role of antibiotics and steroids • Clinical features• Diagnosis• Treatment

Etiology Filamentous fungi : eg :: Septate : Aspergillus , Penicillium, Fusarium :: Aseptate : Mucor , Rizopus• Yeast : eg :: Candida , Cryptococcus• Dimorphic fungi : eg :: Histoplasma , Coccidioides , Blastomyces

Most commonly mycotic corneal uncler is caused by : Aspergillus , Candida , Fusarium

Modes of Infection• Injury by vegetative material : corp

leaf , branch of tree , straw , hay- commonly affects field workers especially during harvesting seasons.

• Injury by animal tail • Secondary fungal ulcers: common in

immunosupresed ,in patients with dry eye , herpetic ulcer , bullous keratopathy or post operative cases of keratoplasty

Role of antibiotics and steroids

• Antibiotics disturbs the symbiosis between bacteria and fungi and steroids make fungi facultative pathogen.

• Excessive use of them predisposes the patients to fungal infection

Clinical features

• Symptoms : *Pain , foreign body sensation – due to

mechanical effects of lids and chemical effects of toxins on exposed nerve ending

*Watering of eyes – due to reflex lacrimation * Photophobia – intolerance to light due to

stimulation of nerve ending * Blurred vision – due to corneal haze * Redness – congession of circumcorneal vessels

Clinical features (cont..)Signs:• Corneal ulcer is dry looking, greyish

white, with elevated role margins• Pigmented ulcer :caused by

dermatiaceous fungi• Feathery finger like extension into

stroma under the intact epithelium• Sterile immune ring : where fungal

antigen and host antibodies meet

Clinical features (cont..)Signs( cont..)• Multiple small satellite lesions around

the ulcer• Big hypopion – not sterile ( fungi can

penetrate into the anterior chamber)• Endothelial plague – composed of fibrin and

leucocytes , under stromal lesion• Perforation ( rare)• Corneal vascularization is absent

Diagnosis• By typical clinical manifestation with history of injury by

vegetative material• Chronic ulcer worsen with most effective treatment –

suspicion of mycotic involvement• Lab Diagnosis : Wet KOH, Colcoflour

white, Grams stain , Culture on Sabourauds agar media• Confocal microscopic examination • PCR Sample Collection :Corneal scraping – from base and edgeAnterior chamber parancentesisCorneal biopsy

Treatment• Specific Treatment: * Topical antifungal eye drops -for 6 to 8

week- Natamycin (5%), Amphotericin B( 0.1% to 3%)- for every 1 hr initially then tapered over 6 to 8 weeks; Nystatin (3.5%) eye ointment 5 times a day.

* Intracorneal or intrastromal administration- of voriconazole in cases intraocular extension or anterior chamber .

* Systemic antifungal – in sever cases of deeper fungal keratitis- tablet fluconazole or ketoconazole for 2 -3 weeks

Treatment ( cont..)• Nonspecific : * Cycloplegic drugs : 1% atropin , homatropine 2% - to reduce pain from cilliary spasm - to prevent posterior scynechiae from secondary

iridoclyclitis. - Increace blood supply to relieve pressure and bring

more antibodies in aqueous humour - reduce exudation by decreasing hyperemia and

vascular permeabily * Systemic analgesics and anti inflammatory – paracetamol and

ibuprofen

• Therapeutic penatrating keratoplasty - for nonresponsive cases

For