The Role of Topical Steroids in Bacterial Keratitis: An Evidence-Based Clinical Review

Purpose: Bacterial keratitis remains a sight-threatening ocular emergency requiring prompt diagnosis and treatment. The role of adjunctive topical corticosteroids in bacterial keratitis has been debated for decades, with conflicting evidence regarding their benefits and risks. This comprehensive review synthesizes current evidence to provide clinicians with practical guidance on the judicious use of corticosteroids in bacterial keratitis. Methods: We conducted a narrative review of the literature, with emphasis on landmark clinical trials including the Steroids for Corneal Ulcers Trial (SCUT), systematic reviews, and recent studies examining the pathophysiology, clinical outcomes, and complications associated with corticosteroid use in bacterial keratitis. Results: The evidence demonstrates that adjunctive corticosteroids may improve visual outcomes in carefully selected patients, particularly those with severe, culture-proven bacterial keratitis involving central, vision-threatening ulcers. The primary SCUT analysis found no significant difference in 3-month best spectacle-corrected visual acuity (BSCVA) between corticosteroid and placebo groups (−0.009 logMAR; 95% CI, −0.085 to 0.068). However, post hoc subgroup analyses suggested potential benefit in patients with baseline vision ≤20/400 (0.17 logMAR improvement; 95% CI, −0.31 to −0.02; p = 0.03) and those with completely central ulcers (0.20 logMAR improvement; 95% CI, −0.37 to −0.04). A secondary analysis suggested that patients with invasive Pseudomonas aeruginosa strains may achieve approximately 2.5 lines of additional visual improvement, though this finding requires prospective validation. Importantly, other evidence has raised concerns that corticosteroids may delay healing in Pseudomonas keratitis, particularly with cytotoxic strains or early initiation. Benefits are highly dependent on appropriate timing (after 48–72 h of effective antibiotic therapy with documented clinical improvement) and exclusion of fungal or atypical infections, where corticosteroids are absolutely contraindicated. Risks include delayed bacterial clearance, corneal perforation (0.8% in the SCUT trial), and potential facilitation of intraocular spread. High-risk scenarios—including diagnostic uncertainty, immunocompromised patients, and those with pre-existing glaucoma—require extreme caution. Conclusions: Topical corticosteroids represent a potentially valuable adjunctive therapy in bacterial keratitis when applied with rigorous patient selection, optimal timing, and careful monitoring. The decision to initiate steroids must be guided by culture confirmation, documented antibiotic response, and ongoing risk–benefit assessment. Emerging diagnostic technologies, including rapid molecular testing and tear biomarker analysis, hold promise for refining these therapeutic decisions in the future.