Abstract
Purpose :
The purpose of this study is to investigate for possible factors before A CXL that can predict the progression of keratoconus postoperatively.
Methods :
This is a prospective observational study including all the patients followed for keratoconus and treated by A CXL between March 2014 and November 2016 at the CHR of Metz with two years follow up. The procedure was the same for all patients: an accelerated protocol of crosslinking (de-epithelialization, 30 minutes of impregnation with Riboflavine then 10 minutes of irradiation with UVA at intensity of 9mW / cm^2, IROC UV-X ™ 2000 Medeuronet). The indication was fixed based on progression of the keratoconus: decrease of the minimum thickness of the cornea (TP) of 10%, increase of a diopter of the maximum curvature anterior of the cornea (Kmax) or loss of a diopter of astigmatism. All patients underwent corneotopography preoperatively and at follow-up up to 2 years. We then formed two groups: the first group where the patients showed no sign of progression after A CXL and the second in which the patients presented it.
Results :
In total, we included 85 eyes. The average age was 24 +/ - 7 years old and there were 33% women. 70% showed no sign of progression at 2 years (group 1) and 30% showed sign of progression (group 2). In each group we measured preoperative visual acuity (0.3 + - 0.21LogMAR in group 1 vs 0.3 + - 0.16LogMAR in group 2 p = 0.96), TP (457 + - 36μ VS 454.6 + - 21.48μ p = 0.88), the Kmax (55.51 + - 4.86D vs 59.90 + - 6.10D p = 0.09), the maximum posterior curvature (-9.30 + - 1.22D vs -10.20 + - 1.31D p = 0.11), the eccentricity of the cone (1.3 + - 0.36mm vs 1.18 + - 0.44mm p = 0.4) and astigmatism (-2.68 + - 1.91D vs -3.52 + - 1.62D p = 0.21).
Conclusions :
Of all the factors studied, only the curvature of the cornea seems to have an impact on the progression of keratoconus after treatment with A CXL. Indeed, in group 1, the average Kmax equals 55.51D whereas it is 59.90D in group 2. A larger-scale study would be useful in order to confirm this hypothesis and to take in charge quickly patients with keratoconus and high Kmax.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.