Adverse events in corneal collagen crosslinking (CXL) alone, CXL with intrastromal corneal ring segments, and CXL with topo-guided PRK

Authors: Wendy Hatch, Stephan Ong Tone, Matthew Bujak, Clara Chan, Hall Chew, Sherif El Defrawy, Christoph Kranneman, Raymond Stein, Theodore Rabinovitch, David Rootman, Allan Slomovic, Vera Stiuso, Lacey Haines, Kostadinka Bizheva, Luigina Sorbara, Neera Singal

Author Disclosure Block: W. Hatch: Alcon. S. Ong Tone: None. M. Bujak: None. C. Chan: Alcon, Allergan, Bausch and Lomb, Santen, Shire, Tear lab. H. Chew: None. S. El Defrawy: None. C. Kranneman: None. R. Stein: None. T. Rabinovitch: AbbVie, Alcon, Bayer, Johnson & Johnson. D. Rootman: None. A. Slomovic: AbbVie, Alcon Canada, Allergan, Bausch and Lomb, Santen, Shire. V. Stiuso: Alcon. L. Haines: None. K. Bizheva: None. L. Sorbara: None. N. Singal: None.

Abstract Body:

Purpose: To describe the adverse events (AEs) from collagen crosslinking (CXL) alone, CXL with simultaneous intrastromal corneal ring segments (CXL-ICR) and with topography-guided photorefractive keratectomy (CXL-TG-PRK) in subjects with progressive keratoconus, pellucid marginal degeneration (PMD) or laser in-situ keratomileusis (LASIK)-induced ectasia.

Study Design: Prospective single- centre non-randomized observational study

Methods: AEs were defined as a change from preoperative to postoperative as follows: intraocular pressure (IOP) increase of 10 mm Hg or more at 1, 3, 6 or 12 months, central corneal thinning (CCT) measured by ultrasound of 100 μm or more at 1 year,a decrease in minimum corneal thickness (MCT) measured by corneal topography and tomography of 100 μm or more at 6 or 12 months, loss of best corrected visual acuity (BCVA) of 3 or more lines at 1, 3, 6 or 12 months, significant haze at 3, 6 or 12 months, 10% or more reduction in endothelial density, infection, scarring or other unanticipated events.

Results: Subjects: 924 eyes of 532 subjects. 676 eyes, 126 eyes, and 122 eyes underwent CXL alone, CXL-ICR and CXL-TG-PRK respectively. AEs: 9, 0, 4 and 6 cases of IOP rise at 1, 3, 6 and 12 months respectively;10 cases of CCT thinning at 12 months; 15 and 17 cases of MCT decrease at 6 and 12 months respectively; 45, 20, 11 and 6 cases of BCVA loss at 1, 3, 6 and 12 months respectively; 11, 16 and 6 cases of significant haze at 3, 6 and 12 months; 1 infection, 1 ulcer, 8 scarring, 3 ICR removed and 1 ICR adjusted, 1 flap edge lift requiring a suture.

Conclusions: Significant loss in BCVA and haze at 1 year were found in very small proportions of the cohort. The haze did not result in significant visual impairment in most cases. Considerable variability  was found in the measurements of CCT, and limitations in the measurement of MCT. The AE rate was low in all three procedures.