Delay in diagnosis and outcome of Acanthamoeba keratitis

Purpose: To evaluate the outcome of Acanthamoeba keratitis with respect to the delay in diagnosis. Methods: A retrospective review of the records of 14 patients treated for Acanthamoeba keratitis was carried out. Delay in diagnosis was correlated with risk factors, clinical presentation, method of diagnosis, final Visual acuity and need for penetrating keratoplasty. Results: Based on the time interval between the first symptoms and the diagnosis of Acanthamoeba keratitis, it appeared that patients could be divided into two groups: an early treatment group (group I), consisting of six patients treated within 18 days of onset of symptoms, and a late treatment group (group II), composed of eight patients treated beyond that time. There were no statistically significant differences between the two groups as far as risk factors, clinical presentation, accuracy of diagnosis and method of diagnosis were concerned, although more extensive and deeper corneal involvement was noted in group II. Improvement in visual acuity following medical therapy was seen in all six patients in the early group and in three (37%) of the eight patients in the late group. One patient in group I needed urgent penetrating keratoplasty for corneal necrosis. In group II, two patients underwent penetrating keratoplasty a chaud to prevent corneal perforation and three patients needed penetrating keratoplasty to restore functional visual acuity. Conclusion: A diagnostic delay of less than 18 days between onset of symptoms and start of anti-amoebic treatment results in a better final VA after medical treatment and obviates the need for urgent and elective penetrating keratoplasty.