Early Results Of Laser-assisted Collagen Cross-linking (laser CXL) Suggest That Patients Achieve Better-uncorrected Acuity At 6 Months Compared To Mechanical Debridement Of The Epithelium In Patients With Progressive Keratoconus

Abstract

Purpose: : To compare the visual outcomes of Laser-assisted collagen cross-linking (Laser CXL) to conventional CXL

Methods: : Laser -assisted collagen cross linking (Laser CXL) is a technique whereby the epithelium is removed in a PTK mode combined with a smoothing solution to create a more regular anterior surface of the cornea in contrast to removing the epithelium manually prior to collagen cross linking in patients with progressive keratoconus. We analyzed the uncorrected acuity at 6 months in 32 patients with progressive keratoconus who had undergone collagen cross linking. 6 patients had undergone Laser CXL and 26 patients had undergone conventional cross linking (CXL) using the Dresden technique. The two groups were analyzed to determine if there were any differences in visual outcomes between the two groups.

Results: : The mean age groups of the two groups were similar (22.5 yrs(laser group) vs 23.5 years(mechanical group). In the laser group the mean uncorrected acuity improved by 3.1 lines vs. the mechanical group, which improved, by only 1.5 lines. In the laser group 0% of patients lost any lines of vision compared to the mechanical group where 30% lost 1 or more lines. In the laser group 83% of patients gained 1 or more lines of acuity compared to 53% in the mechanical group. In the laser group 50% of patients gained 4 or more lines of acuity compared to 34% in the mechanical group. The differences between the two groups failed to reach statistical significance (p=. 20) because of the small sample size and the large standard deviation in the two groups.

Conclusions: : Early results suggest that Laser CXL gives better early visual outcomes than standard CXL using the "epi- off" technique. Uncorrected acuity using this technique is superior to any published data of "epi-on" studies. This technique appears to be not only effective in stopping the progression of keratoconus but also in improving uncorrected acuity. Further longitudinal data in larger sample sizes need to be studied to determine if Laser-CXL should become the preferred technique for removing the epithelium during cross-linking.

Clinical Trial: : http://www.clinicaltrials.gov NCT01081561

Keywords: keratoconus • cornea: clinical science • refractive surgery: other technologies