The Impact of Corticosteroid Use on the Prognosis of Fungal Keratitis

Objective: To assess the impact of the pre-diagnostic use of corticosteroid on the prognosis of visual outcomes and treatment methods of fungal keratitis. Methods: This was a retrospective consecutive case cohort study. Two hundred and eleven eyes of 211 patients diagnosed with fungal keratitis from December 2014 to December 2015 in Shandong Eye Hospital were analyzed. Thirty-six eyes of 36 patients with a history of corticosteroid use before the diagnosis was the corticosteroid group. The remaining 175 eyes of 175 patients with no use of corticosteroid before or during the treatment was the control group. Patients' demographics, clinical findings, management details, changes after the antifungal therapy, and corrected distance visual acuity 2 months after the cure were recorded. Independent samples t test and chi-square test were used for statistical analysis. Results: The demographic data were matched between the two groups. The fungal onset time of the corticosteroid group was 14.5±10.1 days, which was significantly shorter than that of the control group, 20.6±22.5 days (t=2.657, P=0.008). The mean diameter of corneal lesions was 6.3±2.4 mm in the corticosteroid group, which was significantly larger than that of the control group 4.8±2.1 mm (t=3.683, P<0.001). The positive rate of a corneal scrape was 97.2% in the corticosteroid group and 90.6% in the control group, with no significant difference between the groups (χ2=1.633, P=0.201). Only 1 case (2.8%) in the corticosteroid group was cured by antifungal drugs, which was significantly lower than that of the control group, with 34 cases (19.4%) (χ2=5.983, P=0.014). Penetrating keratoplasty was performed in 22 cases (61.1%) in the corticosteroid group, a proportion that was significantly higher than that in the control group, with 55 cases (31.4%) (χ2=11.351, P=0.001). A corrected distance visual acuity of less than 0.3 after antifungal therapy was recorded in 32 cases (88.9%) in the corticosteroid group, a proportion which was significantly higher than in the control group, 110 cases (62.8%) (χ2=9.194, P=0.002). Conclusions: Corticosteroid use before a diagnosis of fungal keratitis can increase the range of lesions, while antifungal drugs seem to be less effective, which increases the probability of penetrating keratoplasty and a poorer outcome. Key words: corticosteroid; fungal keratitis; prognosis