Abstract
Purpose: :
Clinical outcomes were assessed after corneal collagen crosslinking (CXL) for keratoconus (KC) and ectasia.
Methods: :
CXL (UVX; Peschke Meditrade GmbH), was performed on 59 eyes (50 patients), 40 eyes with KC and 19 eyes with ectasia, in a prospective, randomized, controlled clinical trial. Clinical outcomes including uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest cylinder, and manifest refraction spherical equivalent (MRSE) were assessed pre- and 1 year postoperatively. Topography changes using the Pentacam; Kmax and Kavg, were also determined. Corneal biomechanical parameters, corneal hysteresis (CH) and corneal resistance factor (CRF) were measured using the Ocular Response Analyzer (ORA)(Reichert Inc.).
Results: :
In the entire cohort, mean UCVA preoperatively was 20/149 and postoperatively was 20/133 (p=0.11). BCVA was significantly improved from 20/47 to 20/35 (p<.001). MRSE improved by 1.9D (p=0.04), although manifest cylinder remained unchanged after CXL. Topographically, Kmax and Kavg flattened by 2.5D (p=0.01) and 0.8D (p<.001), respectively, at 1 year. ORA parameters, CH and CRF did not significantly change following CXL.In the stratified subgroups, KC eyes showed no significant change in UCVA while BCVA improved from 20/51 to 20/37 (p<.001). MRSE improved by 1.0D (p=0.11), but failed to reach statistical significance. Manifest cylinder remained the unchanged after CXL. Topographically, Kmax and Kavg, flattened by 3.1D (p=0.02) and 0.8D (p<.001), respectively. No significant changes in CH or CRF were seen. Similarly, ectasia eyes, showed no significant change in UCVA while BCVA improved from 20/38 to 20/30 (p=0.003). MRSE improved by 1.5D (p=0.21) but failed to reach statistical significance. Manifest cylinder remained unchanged after CXL. Topographically, mean Kmax decreased by 1.1D (p=0.08), and Kavg failed to reach significance as well. No significant changes in CH or CRF were seen.
Conclusions: :
Overall, CXL was effective at improving BCVA, MRSE, Kmax, and Kavg. At 1 year postoperatively, more topographical changes were significant in patients with KC than ectasia. Cornea biomechanical parameters, CH and CRF were unchanged.
Clinical Trial: :
www.clinicaltrials.gov NCT 00647699, NCT 00674661
Keywords: keratoconus • clinical (human) or epidemiologic studies: outcomes/complications • refractive surgery: other technologies