A major randomised clinical trial has found that adjunctive topical corticosteroids and corneal cross-linking do not improve outcomes in bacterial keratitis beyond topical antibiotics alone, with cross-linking actually increasing scar size.
The SCUT II trial, published in JAMA Ophthalmology, challenged current clinical practices by demonstrating that these commonly considered adjunctive therapies may not provide the expected benefits for patients with bacterial corneal ulcers.
these findings suggest alternative therapies may not be superior to topical antibiotics alone for bacterial keratitis treatment
The National Institutes of Health-funded study involved 280 participants with smear- and/or culture-positive bacterial corneal ulcers across clinics at the Aravind Eye Hospitals in India and Bascom Palmer Eye Institute in Miami, Florida, between September 2020 and October 2023.
No Visual Acuity Improvement
The primary finding revealed no difference in six-month visual acuity when comparing adjunctive topical steroids to placebo, or when comparing adjunctive corneal cross-linking (CXL) plus steroids to steroids alone.
“After controlling for baseline, there was no difference in six-month visual acuity with adjunctive topical steroids versus placebo,” the researchers reported, finding a difference of just -0.04 logMAR (95% CI, -0.18 to 0.09; P = .58).
Similarly, adjunctive CXL combined with topical steroids showed no improvement over topical steroids alone, with a difference of 0.04 logMAR (95% CI, -0.09 to 0.17; P = .62).
Cross-Linking Increases Scar Size
Particularly concerning was the finding that CXL plus corticosteroids significantly increased scar size compared with steroids alone. After controlling for baseline infiltrate and/or scar size, the CXL group showed an increase of 0.56 (95% CI, 0.20-0.92; P = .02).
Further, adjunctive topical corticosteroids did not improve scar size at six months after controlling for baseline infiltrate and/or scar size (-0.22; 95% CI, -0.53 to 0.10; P = .65).
Perforation Risk Unchanged
The study also examined rates of corneal perforation and the need for therapeutic penetrating keratoplasty (TPK). Results showed 0.78 times the hazard of perforation or need for TPK in the early-steroid arm (95% CI, 0.27-2.24; P = .65) and 0.48 times the hazard in the CXL arm (95% CI, 0.14-1.67; P = .25) after controlling for infiltrate depth.
Clinical Implications
Lead researcher Professor N. Venkatesh Prajna, FRCOphth, from Aravind Eye Hospitals, and colleagues concluded that these findings suggest alternative therapies may not be superior to topical antibiotics alone for bacterial keratitis treatment.
Reference
Prajna NV, Lalitha P, Rose-Nussbaumer JR, et al. Steroids and Cross-Linking for Ulcer Treatment: The SCUT II Randomized Clinical Trial. JAMA Ophthalmol. 2025 Jul 24:e252188. doi: 10.1001/jamaophthalmol.2025.2188.
