Microbiology, risk factors and outcomes of microbial keratitis in Sydney, Australia
Reviewed by Kurt Spiteri Cornish

The authors present a retrospective case series including all patients with microbial keratitis and ocular surface diseases (OSD), including dry eye, blepharitis, Stevens-Johnson syndrome and / or ocular cicatricial pemphigoid, over a five-year period between 2012 and 2016. A total of 1052 cases were included in this study. Blepharitis was the most prevalent OSD, present in 79% of patients, followed by dry eye in 25%. The commonest systemic disease was diabetes mellitus (12%), followed by asthma / chronic obstructive pulmonary disease (10%). Additional predisposing factors were contact lens wear (33%) and corticosteroid use (13%). The most common contact lens-related risk factors were water-related activities such as swimming and showering with lenses and overnight or extended wear. Of the eyes with known outcomes, 44% had a good, 9% a moderate and 47% a poor outcome. The latter was correlated with combination therapy with fortified antibiotics (compared to monotherapy). This could be explained by the associated ocular surface toxicity. There was no significant difference between the groups of OSD, the initial and final clinical features. The most common complication was non-healing or slow-healing epithelial defect (34%), corneal perforations (20%) and increased intraocular pressure (19%). The study confirms that presence of OSD is a significant risk factor for developing microbial keratitis. This may be due to reduction or alteration in the tear film leading to reduction in tear proteins and can lead to disruption of corneal epithelium leading to openings for microbial invasion.

Microbial keratitis and ocular surface disease: A 5-year study of the microbiology, risk factors and clinical outcomes in Sydney, Australia.
Khoo P, Cabrera-Aguas M, Robaei D, et al.
CURRENT EYE RESEARCH
2019;44(11):1195-202.