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### Abstract

#### Importance

Corneal abrasions are frequent after standard (epithelium-off [epi-off]) corneal collagen cross-linking (CXL) in patients with progressive keratoconus. A new matrix therapy agent (ReGeneraTing Agent [RGTA]) has been developed to promote corneal wound healing.

#### Objective

To assess the effect of the new type of matrix therapy agent on corneal wound healing after epi-off CXL in patients with keratoconus.

#### Design, Setting, and Participants

This double-masked randomized clinical trial enrolled 40 patients with keratoconus undergoing epi-off CXL from July 18, 2014, to October 21, 2015, when the last follow-up was completed. The analysis of the intention-to-treat population was performed at the Department of Clinical Pharmacology in cooperation with the Center for Medical Physics and Biomedical Engineering and the Department of Ophthalmology and Optometry of the Medical University of Vienna.

#### Interventions

Patients were randomized to receive the matrix therapy agent or hyaluronic acid-containing eyedrops, 0.1%, every other day starting immediately after surgery. The size of the corneal defect was measured using ultrahigh-resolution optical coherence tomography (OCT) and slitlamp photography (SLP) with fluorescein staining.

#### Main Outcomes and Measures

Corneal wound healing rate, defined as the size of the defect over time.

#### Results

Among the 40 patients undergoing epi-off CXL (31 men; 9 women; mean [SD] age, 31 [10] years), wound healing was significantly faster in the matrix therapy agent group compared with the hyaluronic acid group (4.4 vs 6.1 days; mean difference, 1.7 days; 95% CI, 0.25-3.15 days; P = .008). The defect size was smaller in the matrix therapy agent group than in the hyaluronic acid group as measured with OCT (12.4 vs 23.9 mm2; mean difference, 11.6 mm2; 95% CI, 0.8-23.5 mm2; P = .045) and SLP (11.9 vs 23.5 mm2; mean difference, 11. 6 mm2; 95% CI, 1.3-22.9 mm2; P = .03). A correlation between the defect size measured with OCT and SLP was found (r = 0.89; P<.001). No ocular or serious adverse events occurred.

#### Conclusions and Relevance

Use of a new matrix therapy agent appears to improve corneal wound healing after CXL in patients with keratoconus. Monitoring of corneal wound healing using ultrahigh-resolution OCT might be an attractive alternative to SLP because OCT provides an objective and 3-dimensional evaluation of the corneal defect.

#### Trial Registration

clinicaltrials.gov Identifier: NCT02119039.