keratitis , especially when long - standing and unresponsive to common antimicrobial treatment , leads to a suspicion of fungal aetiology . a 65-year - old man with diabetes was referred for corneal abscess unresponsive to antibiotic and antifungal treatment lasting 6 weeks . a 65-year - old italian farmer with orally treated diabetes was referred to us for a left eye corneal abscess unresponsive to topical antibiotic and anti - inflammatory treatment lasting 6 weeks . the patient had suffered a cow - tail trauma 20 years earlier in the same eye . this gave rise to a central corneal ulcer and poor vision ( 20/160 , measured with the early treatment of diabetic retinopathy study ( etdrs ) chart ) . after a more recent trauma , the patient was hospitalised due to a corneal abscess in the same eye . owing to the lack of response to various antimicrobial local drugs , i.e. tobramycin 0.3% drops 8 times / day and ampicillin 0.8% drops 4 times / day , even associated with steroid eyedrops , i.e. dexamethasone 0.3% eyedrops , all with preservatives , fungal infection was suspected despite negative corneal scraping . this suspicion was ( psychologically ) strengthened in the treating ophthalmologist for three reasons : the corneal ulcer had been caused by a mild agricultural trauma , the patient was diabetic , and the clinical history and the corneal picture were suggestive of fungal keratitis . before referral to us , systemic and local ketoconazole 0.4% ( 3 times / day ) and topic levofloxacin 0.5% ( 4 times / day ) had been unsuccessfully administered for two weeks . thus , we were asked to perform extreme antifungal treatment with corneal intrastromal voriconazole . at admission , severe conjunctival hyperhaemia with 360 corneal neovascularisation , a central , ulcerative , abscess - like keratopathy with a satellite lesion , and hypopion were evident ( fig . a corneal biopsy was performed following a 72-hour washout for identification of bacteria and fungi . previously administered drops were withdrawn and preservative - free artificial tears and cycloplegics were given instead . neither bacteria nor fungi were found . over the next 2 weeks , the clinical picture improved and resolved 4 weeks later : conjunctival hyperhaemia was significantly reduced , hypopion and corneal infiltrates had disappeared , and the corneal stroma appeared more transparent ( fig . the clinical picture was similar to the one described clinically after healing from the coil trauma . in clinical practice , the ophthalmologist is often tempted to treat ocular inflammation without a working diagnosis and microbiological confirmation , especially if coping with a poorly cooperative patient . in this specific case , very probably , an asymptomatic central corneal epithelial defect persisted after the earlier cow - tail trauma . clinical signs of toxic keratopathy are usually so nonspecific that a diagnosis can only be confirmed by withdrawing suspected medications and drops with preservatives .
background / aimskeratitis , especially when long - standing and unresponsive to common antimicrobial treatment , leads to a suspicion of fungal aetiology.methodsphotographically documented case report.resultsa 65-year - old man with diabetes was referred for corneal abscess unresponsive to antibiotic and antifungal treatment lasting 6 weeks . 
 corneal biopsy was performed following a 72-hour washout for identification of bacteria and fungi . 
 previously administered drops were withdrawn and only preservative - free artificial tears were maintained . 
 neither bacteria nor fungi were cultured . after 2 weeks , 
 the clinical situation had conspicuously improved.conclusionover-treatment of corneal affections fearing mycosis may lead to toxic keratopathy .