Jenny Xue Tian1, Stephanie L Watson3 ,4, Dana Robaei3 ,4, Yi-Chiao Li2 ,3, Lisa Keay5

Purpose: To investigate the risk factors associated with microbial keratitis, in particular a possible association between the use of topical antiglaucoma medication and the severity of microbial keratitis at presentation and discharge.

Method: A retrospective study of all patients admitted to Sydney Eye Hospital with clinically presumed microbial keratitis between 1/1/2012 and 31/12/2013 (inclusive) was conducted. Data recorded included demographic details, relevant risk factors, number of topical antiglaucoma medications, clinical features including vision at presentation, results of microbiological studies, and clinical and visual outcomes at discharge.

Results: Of the 232 patients admitted for microbial keratitis 53 patients (23%) were on topical antiglaucoma medications. At presentation, patients on topical antiglaucoma medications were significantly older (mean age 82±13 vs. 55±22 years, p<0.001), had worse visual acuity (mean LogMAR 2.06±0.79 vs. 1.30±1.02, p<0.001) and a higher rate of hypopyon (57% vs. 34%, p=0.009) than patients not on antiglaucoma medication. At discharge, they had worse visual outcome (mean LogMAR 2.26±0.82 vs. 1.09±1.10, p<0.0001), longer duration of hospital stay (12±11 vs. 9±7 days, p=0.01), a higher rate of cornea perforation (15% vs. 3%, p=0.004) and evisceration (15% vs. 4%, p=0.008). Multivariate analysis showed that the number of topical antiglaucoma medications was independently predictive of length of hospital stay (p=0.01) adjusting for age, whereas the age of the patient was predictive of the visual acuity at presentation (p<0.0001) and discharge (p<0.0001).

Conclusion: Topical antiglaucoma medication use was common amongst hospitalised cases of severe microbial keratitis. Their use was associated with longer hospital stay, independent of age.