SEVERE MICROBIAL KERATITIS IN TEMPERATE AND TROPICAL WESTERN-AUSTRALIA

To determine the patterns of severe microbial keratitis in Western Aus tralia, all acute admissions over a 2 year period to the Department of Ophthalmology, Royal Perth Hospital were assessed, Fifty-three cases (n = 53) of severe, presumed microbial keratitis were identified. Seve nty per cent of these eyes had a visual acuity of 6/60 or less on admi ssion and only 38.8% had 6/12 or better corrected acuity following res olution of the keratitis. The most commonly identified predisposing fa ctors were: prior ocular surgery with or without exposed monofilament sutures (43.4%); contact lens wear (22.6%); lid malposition (17.0%); h istory of ocular trauma (15.1%); and history of previous herpes simple x keratitis (13.2%), It is notable that 26.4% of the subjects had been applying topical ophthalmic corticosteroids prior to admission. Follo wing corneal scrape or biopsy a positive microbial diagnosis was made in 71% of samples, with Gram-negative and Gram-positive bacterial isol ates being equally frequent. Five cases of Acanthamoeba keratitis were identified following corneal biopsy. Where antibiotic sensitivities w ere available, it was noted that 61.5% of Grampositive and 46.1% of Gr am-negative bacteria were susceptible to chloramphenicol, with 84.6% o f Gram-negative bacteria being sensitive to gentamicin. Many of these severe cases of microbial keratitis might have been avoided, or their severity lessened, by earlier identification of predisposing risk fact ors, more intensive and appropriate antibiotic administration, and imp roved patient education following ocular surgery.