Posters

Comparison between epithelial off cross-linking (Epi-off CXL) with iontophoresis-assisted cross-linking (I-CXL) in keratoconus patients in a referral center of ophthalmology in Mexico City

Poster Details

First Author: C.Tlapanco Beltrán MEXICO

Co Author(s):    A. Medina Andrade   N. Dávila Avila   P. Domínguez Castillo   N. Ramos Betancourt   V. Sánchez Huerta        

Abstract Details

Purpose:

To compare long term results of epithelial off cross-linking (Epi-off CXL) with iontophoresis-assisted cross-linking (I-CXL) in keratoconus patients in a referral center of ophthalmology with a follow up of 36 months.

Setting:

I-CXL is an epithelium-on technique that uses a low-intensity electric field which allows riboflavin to penetrate the intact epithelium, however the concentration reached seems to be less than in Epi-off CXL. Some comparative studies show I-CXL is less effective to treat keratoconus progression than Epi-off CXL.

Methods:

A retrospective, comparative study was carried out. Clinical records of 101 patients with progressive keratoconus who were treated at Association to Prevent Blindness, Mexico, between 2014 and 2018 were included. 69 eyes who were treated with Epi-off CXL were compared with 32 eyes treated with I-CXL. Mann Whitney U test and Chi-square were used to compare characteristics between groups. An ANOVA analysis between gold stardard (Epi off CXL) and I-CXL was performed.  p level of <0.05 was considered significant. Statistical analyses were performed using SPSS 24.0 (SPSS, Inc., Chicago Illinois).

Results:

No statistically significant differences between groups at baseline in refractive and corneal characteristics was found. Considering Kmax as the best indicator of keratoconus progression, no statistically significant differences were found between groups at 6 months (p=0.09), 12 months (p= 0.79), 24 months (p=0.23) and 36 months (p=0.66).  There was no difference in BCVA in the Epi-off CXL group at 36 months of follow up. The BCVA in the I-CXL group improved from 0.43±0.35 to 0.21±0.14 logMAR at 36 months (p=0.78). A post hoc analysis was carried out, no statistically significant differences were found in refractive parameters at 36 months.

Conclusions:

The Dresden protocol is the gold standard treatment in keratoconus progression. However, this technique is associated with risk of infection, infiltrates and haze. I-CXL is a noninvasive technique that uses an electrical current to enhance the penetration of riboflavin into tissue, circumventing corneal epithelial removal, nonetheless allowing efficient collagen cross-linking. In this study, we conclude that there is no statistically significant differences between the two groups studied (Epi-off CXL vs I-CXL) in terms of best corrected visual acuity, sphere, cylinder, Kmax, Kmin and thinnest pachymetry at 36 months of follow up. 

Financial Disclosure:

None