EARLY DIAGNOSIS OF ACANTHAMOEBA-KERATITIS

Background Acanthamoeba keratitis is an uncommon condition which is us ually associated with contact lens wear. The use of home made saline a nd poor hygiene are important risk factors. Early diagnosis is crucial since these cases respond well to medical therapy. The purpose of thi s paper is to describe and demonstrate early clinical signs. Method Be tween September 1992 and October 1994, 70 cases of acanthamoeba kerati tis, one of them bilateral, were prospectively monitored at Moorfields Eye Hospital in London. A database of all patients was set up and the clincial findings, diagnostic methods, therapeutic interventions and the outcome were recorded. Results 66 patients (96%) were contact lens wearers, 64 of them (97%) wore soft lenses. The mean intervall betwee n first symptoms and correct diagnosis was 42%. The most frequent init ial diagnoses were ''unclear keratoconjunctivitis'' and ''herpetic ker atitis''. Early corneal findings included punctate keratopathy (n=14; 20%), pseudodendrites (n=4; 6%), epithelial infiltrates (n=17; 24%), d iffuse or focal subepithelial infiltrates (n=36; 51%) and radial kerat oneuritis (n=5; 7%). Ring infiltrates (n=13; 18%) and corneal ulcerati on (n=13) were late signs. Conclusion When the above corneal findings are observed, particularly in contact lens wearers, the diagnosis of a canthamoeba keratitis should be considered. The diagnosis of ''herpeti c keratitis'' in association with contact lens wear should be encounte red with scepticism.