Contact lens microbial keratitis and prior topical steroid use: a disaster in the making?

INTRODUCTION: To review the best-corrected visual acuity, ulcer size, microbiological profile and morbidity of contact lens-related microbial keratitis with and without prior topical steroid use.
MATERIALS AND METHODS: Retrospective case review of admitted cases of contact lens-related microbial keratitis in a tertiary hospital. Data pertaining to demographics, pre-admission treatment with or without topical steroids, ulcer size, duration of admission, Gram stain and culture results as well as the final best-corrected visual acuity were recorded. Patients are classified into 3 groups: Group 1 received no treatment prior to presentation, Group 2 received topical antibiotics only from their general practitioners and Group 3 prescribed both topical antibiotics and steroids.
RESULTS: Forty-six cases were enrolled in the study, 41.3% had prior topical steroids (all dexamethasone) in combination with antibiotics. None of them had topical steroids alone. Large ulcers were associated with steroid use, odds ratio = 7.74 [95% confidence interval (CI), 1.18-50.56] and positivity of Gram stains odds ratio = 7.74 [95% CI, 1.18-50.56] whereas loss of more than 2 Snellen lines was associated with Pseudomonas aeruginosa infection, odds ratios of 21.70 [95% CI,2.09-225.03] and presence of central ulcer, 13.51 [95% CI, 2.33-78.3]. Prior topical steroid use was associated with longer duration of symptoms prior to admission but not duration of stay or surgical intervention.
CONCLUSION: Patients with prior topical combined antibiotics-steroids present slightly later and with larger ulcers. However, the duration of stay, final visual acuity, treatment failure and complication rates were not statistically different from the non-treated group. This might be due to 1) early presentation and therefore early treatment of contact lens-related microbial keratitis and 2) the short duration of use of combined antibiotic-steroid eye drops.