Transepithelial corneal collagen cross-linking in ultrathin keratoconic corneas

Abstract

BackgroundThe purpose of this paper was to report the results of transepithelial corneal collagen cross-linking (CXL) with modified riboflavin and ultraviolet A irradiation in patients affected by keratoconus, each with thinnest pachymetry values of less than 400 μm (with epithelium) and not treatable using standard de-epithelialization techniques.MethodsSixteen patients affected by progressive keratoconus with thinnest pachymetry values ranging from 331 μm to 389 μm underwent transepithelial CXL in one eye using a riboflavin 0.1% solution in 15% Dextran T500 containing ethylenediamine tetra-acetic acid 0.01% and trometamol to enhance epithelial penetration. The patients underwent complete ophthalmological examination, including endothelial cell density measurements and computerized videokeratography, before CXL and at one day, one week, and one, 6, and 12 months thereafter.ResultsEpithelial healing was complete in all patients after one day of use of a soft bandage contact lens. No side effects or damage to the limbal region was observed during the follow-up period. All patients showed slightly improved uncorrected and spectacle-corrected visual acuity; keratometric astigmatism showed reductions (up to 5.3 D) and apical ectasia power decreased (Kmax values reduced up to 4.3 D). Endothelial cell density was unchanged.ConclusionApplication of transepithelial CXL using riboflavin with substances added to enhance epithelial permeability was safe, seemed to be moderately effective in keratoconic eyes with ultrathin corneas, and applications of the procedure could be extended to patients with advanced keratoconus.

Clinical Outcomes at 1 Year following Corneal Ectasia Treatment with Accelerated Transepithelial Cross-linking

“…This is consistent with the findings reported in other series evaluating the results of transepithelial CXL, either by iontophoresis or accelerated. [19][20][21][22][23][24][25][26][27] Similarly, in line with all previous studies on transepithelial CXL, 19-27 a significant improvement in CDVA was observed after surgery that remained throughout the entire 12-month follow-up period. Lesniak and Hersh,24 in a prospective study, evaluated a similar technique and found a mean improvement in CDVA of 0.83 Snellen lines.…”

“…Other studies have evaluated changes in the maximum keratometry after different modalities of transepithelial CXL. [19][20][21][22][23][24][25][26][27] Lesniak and Hersh 24 found a mean reduction of 0.9D in the maximum keratometry in a prospective study that evaluated the results of a similar CXL technique than that used in our study over a 6-month period. It should be borne in mind that this study included keratoconus cases that were more advanced than in our series, so the mean keratometry was higher.…”

“…[14][15][16] For this reason, new CXL protocols are being developed in order to avoid having to debride the corneal epithelium, such as the creation of intrastromal pockets for riboflavin infusion 17,18 or transepithelial CXL, either iontophoresis-assisted or using a benzalkonium chloride solution to increase the permeability of the corneal epithelium. [19][20][21][22][23][24][25][26][27] Although there is some experimental and clinical evidence of the effectiveness of accelerated transepithelial CXL, it is still limited. The aim of the present prospective, noncomparative study was to assess the visual, refractive, topographic, and aberrometric changes in the ectatic corneas after accelerated transepithelial CXL over 1 year of follow-up.…”

Recent Advances in Corneal Collagen Crosslinking in thin Corneas

“…Their combination breaks intercellular bonds, thus facilitating the penetration of riboflavin through the intact epithelium. Applying a similar technique of transepithelial CXL in ultrathin corneas (thinnest pachymetry 331-389 µm) moderate efficacy was reported by Spadea et al 17 However, long term results by Caporrosi et al 18 failed to support this technique. In their 24 months follow up they found keratoconus instability and functional regression particularly in patients less than 18 yrs.…”

Corneal Collagen Crosslinking with Riboflavin and Ultraviolet - A Irradiation in the Management of Progressive Ectatic Corneal Disorders. Review Article

“…Although the great majority of eyes are stabilized after CXL. Koller and coworkers 74 in 177 eyes described progression in 8 eyes (7.6%). They identified eyes with advanced keratoconus with maximum keratometry values greater than 58D of being at greatest danger of progression.…”