• Written By:
    Refractive Mgmt/Intervention

    Review of: Corneal Haze After Transepithelial Collagen Cross-linking for Keratoconus: A Scheimpflug Densitometry Analysis

    J.Lai M, Greenstein S, Gelles J, et al. Cornea, September 2020

    This study attempted to identify the amount and time course of corneal haze development after transepithelial corneal collagen crosslinking (CXL) in patients with keratoconus.

    Study design

    Fifty-nine eyes (43 patients) underwent transepithelial CXL and were randomized to intraoperative hypotonic riboflavin (0.10%) either every 1 or 2 minutes while concurrently receiving proparacaine-BAK (0.01%). Scheimpflug densitometry was measured preoperatively and at various time points during the 12-month follow-up. Densitometry measurements were correlated with visual acuity, pachymetry and topography outcomes.


    Preoperative mean corneal densitometry was 20.5. Mean densitometry significantly increased by 1 month (22.6; P < 0.001), remained stable until 3 months and then declined between 3 and 12 months, returning to baseline levels by 12 months (20.8; P=0.21). There was no significant difference between the 1-minute and 2-minute treatment subgroups. In addition, corneal densitometry at 3 and 12 months did not correlate with uncorrected or corrected distance visual acuity at 12 months.


    The study only assessed development of haze, not the success of treatment. These results may not apply to other types of riboflavin solutions used in the various methods of transepithelial CXL that have been described.

    Clinical significance

    After transepithelial CXL, corneal haze increased slightly at 1 month, plateaued through 3 months and then returned to baseline by 12 months. The density of corneal haze in this study appeared to be less than the haze previously reported for standard cross-linking procedures.