As eye care physicians, we often encounter corneal infections in our patients. Fortunately, most of these infections are mild, respond quickly to standard topical antibiotic treatment alone, and resolve without significant corneal scarring or decreased vision. In those infections that are more severe, however, the risk of visually significant scarring is substantial.
The corneal damage that leads to the scarring can result from both the actual infection and the body's inflammatory response to it. Topical steroids have been used, in conjunction with topical antibiotics, to mitigate the inflammatory response in hopes of minimizing corneal scarring and ideally improving the final visual outcome. As some inflammatory response is usually beneficial in combatting infections, however, suppressing it may have unintended consequences, including worsening infection and corneal melting.
In an attempt to determine the effect of steroids in culture-positive bacterial keratitis, a group of researchers from Australia conducted a review of all eligible patients treated for this infection at their institution between 1999 and 2015.[1] Among other factors, researchers compared visual outcomes in groups who received high-, medium-, and low-dose steroids, as well as no steroids. Their results indicated that very good outcomes can be achieved with the use of high-dose steroid treatment, which they define as prednisolone 1% (or equivalent) six or more times daily. Another important finding was that the rate of corneal transplant or significant visual loss was not statistically significantly different between those who are receiving steroids and those who are not.
Several important limitations should be kept in mind when reviewing this study. For one, its retrospective design means that the treating physician decided whether to use steroids or not, and also whether to use low-, medium-, or high-dose steroids. Although there were not big differences in presenting vision, infiltrate size, central location, presence of hypopyon, or culture results between groups, significantly more eyes had undergone prior ocular surgery in the high-dose steroid group (approximately 53%) than in the other groups (approximately 16%-17%). In addition, the most common risk factor studied was contact lens wear, which was noted in only 16% of those receiving high-dose steroids, but in 40% to 50% of their counterparts receiving medium-dose, low-dose, or no steroids. These differences limit the generalizability of the results. Another weakness of this study is the relatively small number of eyes (19) that received high-dose steroids.
Even with these limitations, I think the overall conclusion that high-dose steroid treatment should be considered in eyes with bacterial keratitis is warranted. This seems to follow larger treatment trends over time, as the authors found that in the first year of the study (1999), only 20% of eyes were treated with steroids, whereas by the last year of the study (2015), 55% of eyes were treated with steroids (although these included low, medium, and high doses).
If a physician is considering starting a patient with infectious keratitis on high-dose steroids, I would advise that they make sure the eye has bacterial keratitis and not another cause of infection, such as fungus or Acanthamoeba. I would also suggest examining the patient within a few days of starting the steroids to make sure the drugs are not causing complications, such as worsening of the infection or corneal thinning or melting.
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Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Christopher J. Rapuano. High-Dose Steroids: Worth the Risk in Bacterial Keratitis? - Medscape - Apr 09, 2019.
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