Corticosteroids can be particularly helpful for treating bacterial keratitis in patients with low vision and those with central ulcers involving the central 4mm pupil, according to a recent Cochrane review. The review compared the use of adjuvant topical corticosteroids versus antibiotics alone.
Brisbane ophthalmic surgeon Dr Sing-Pey Chow says the role of topical corticosteroids in bacterial keratitis has long been debated.
“Even when antibiotics are adequately controlling the infection, final visual outcomes can still be compromised due to corneal scarring and irregular astigmatism. Topical steroids can help address these factors by limiting the inflammatory response associated with infection. However, there are concerns that steroids may delay epithelial healing, exacerbate corneal thinning or even worsen infection,” said Dr Chow.
The Cochrane review compared four randomised controlled trials (RCTs). While the first three small RCTs did not find a difference in visual acuity outcomes or healing times between groups; the fourth and largest RCT was the Steroids in Corneal Ulcer Trial (SCUT).
SCUT was a randomised, double-masked, placebo-controlled clinical trial comparing adjunctive corticosteroids versus placebo in 500 culture-positive bacterial ulcers with patients from the Aravind Eye Care System in India, Dartmouth-Hitchcock Medical Centre in New Hampshire and University of California in San Francisco. Patients were randomised to topical prednisolone sodium phosphate 1.0% versus placebo after a 48-hour course of topical moxifloxacin 0.5%.
Dr Chow said that although the overall data did not show a difference in outcomes at three months including visual acuity, scar size and rate of perforation, subgroup analyses suggest that corticosteroids are helpful in certain subgroups: (i) Patients with low vision (counting fingers or worse) at baseline had 1.7 lines better vision at three months in the steroid group (p=0.03); and (ii) Central ulcers involving the central 4mm pupil had better best spectacle-corrected visual acuity (BSCVA) at three months (p=0.07) in the steroid group.
“Organism subtype was also an important factor when considering adjuvant corticosteroid use. Although there was no difference in BSCVA at three months, ulcers due to the acid-fast atypical bacterium Nocardia had a larger scar size in the steroid group (p=0.03) compared to non-Nocardia ulcers. Meanwhile, ulcers due to the classically invasive subtype of P. aeruginosa demonstrated a 2.5-line improvement in BSCVA at three months when randomised to steroids versus placebo, even though Pseudomonas aeruginosa ulcers overall did not appear to benefit from the addition of steroids.”
2019 MASTERCLASS OPTOMETRIST CONFERENCE
In an update on corneal infections and their complications at the 2019 MasterClass Optometrist Conference in Brisbane on 27 October, Dr Chow will speak in more depth about the role of corticosteroids in treating bacterial keratitis. She will also speak about viral keratitis, fungal keratitis and potential treatment modalities being developed. Other speakers will include Dr Lawrence Lee, who will speak on the myopia epidemic, Dr Lindsay McGrath who will present on anterior segment examination, Dr Diana Conrad who will provide an update on uveitis, Dr Graham Lee on MIGS, and Dr David Hilford on Interpretation of the retina using optical coherence tomography, fundus fluorescein angiography and more.
The Masterclass will be held at QUT’s Gardens Point Campus, Brisbane. Visit: www.2019masterclass.com
- Herretes S, Wang X, Reyes JM. Topical corticosteroids as adjunctive therapy for bacterial keratitis. Cochrane Database Syst Rev. 2014;CD005430.