Microbial keratitis in East Africa: why are the outcomes so poor?

Microbial keratitis (MK) is a major cause of blindness in Africa. This study reports the epidemiology, causative organism, management and outcome of MK in people admitted to a large referral hospital in Northern Tanzania, and explores why the outcomes are so poor for this condition.

A retrospective review of all admissions for MK during a 27-month period. Information was collected on: demographics, history, examination, microbiology, treatment and outcome.

A total of 170 patients with MK were identified. Presentation was often delayed (median 14 days), and more delayed if another health facility was visited first (median 21 days). Appropriate intensive antibiotic treatment was prescribed in 19% before admission. Lesions were often severe (41% >5mm). Filamentary fungi were detected in 25% of all specimens (51% of specimens with a positive result). At discharge, 66% of affected eyes had a visual acuity of less than 6/60. Perforations developed in 30% and evisceration was necessary in 8%. Perforation was associated with large lesions and visiting another health facility. HIV infection was diagnosed in 16% of individuals tested, which is approximately twice the prevalence found in the wider population.

Microbial keratitis is a significant clinical problem in this region, which generally has a very poor outcome. Delayed presentation is a critical issue. Fungal keratitis is a prominent cause and there is an indication that HIV may increase susceptibility. Prompt recognition and appropriate treatment in primary/secondary health facilities and rapid referral when needed may reduce the burden of blindness from this disease.