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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