Predictors for treatment outcomes after corneal crosslinking for keratoconus: a validation study

Abstract

Previous research suggested that baseline corrected distance visual acuity (CDVA) and maximum keratometry (Kmax) are the predictors for effectiveness of corneal crosslinking (CXL) for keratoconus. The aim of this study was to validate the previously determined predictors in a new treatment cohort. A prospective cohort of 112 eyes in 90 consecutive patients was used to validate the results of 102 eyes in 79 patients from our previous prospective cohort. All patients were treated using epithelium-off corneal CXL in a tertiary hospital setting. Primary outcomes were changes in CDVA (LogMAR) and Kmax between baseline and 1-year post-treatment. Predictive factors for both outcomes were determined using univariable and multivariable analyses. Lower pretreatment CDVA was found to be the sole independent factor predicting an improvement in CDVA 1 year after CXL (β coefficient: −0.476, P < 0.01). Kmax flattening is more likely to take place in eyes with preoperative central cones (β coefficient: 0.655, P < 0.01). These results are consistent with our initial research and indicate high reproducibility in the new cohort. The previously postulated prediction model for postoperative CDVA showed limited predictive value in the validation cohort (R 2 = 0.15). The clinical implication of these results is that patients with lower pretreatment visual acuity are more likely to benefit from CXL (with respect to visual acuity), and patients with more central cones will benefit more in terms of cone flattening. Furthermore, those results can be used to guide customization of the crosslinking treatment.

Patient selection for corneal collagen cross-linking: an updated review

“…In addition, unlike the findings in their first cohort, in the validation study they found that younger patients had significantly better results with respect to visual acuity 108,110. Soeters et al113 had also identified age as a prognostic factor 110…”

“…Godefrooij et al110 identified possible predictors for results of the effect of CXL in a prospective cohort, and recently in a different prospective cohort they performed a validation study 108. They found by using univariate analysis that a predictor of higher improvement in K max was male sex, while atopia was a predictor of a slight (but significant) decrease in improvement in visual acuity 108.…”

“…Therefore, they proposed that focusing the UVA light on the cone apex, instead of the geometrical center of the cornea, could improve results in eccentric cones 108. In their validation set, Godefrooij et al110 found similar results to their original prospective cohort 108. Baseline preoperative CDVA was found to be the sole independent factor predicting an improvement in CDVA 1 year after the procedure, with patients with lower pretreatment visual acuity showing higher possibilities to benefit from CXL (with regard to visual acuity) and eyes with more central cones obtaining more benefit from the procedure in terms of corneal flattening 110.…”

“…In their validation set, Godefrooij et al110 found similar results to their original prospective cohort 108. Baseline preoperative CDVA was found to be the sole independent factor predicting an improvement in CDVA 1 year after the procedure, with patients with lower pretreatment visual acuity showing higher possibilities to benefit from CXL (with regard to visual acuity) and eyes with more central cones obtaining more benefit from the procedure in terms of corneal flattening 110. In addition, unlike the findings in their first cohort, in the validation study they found that younger patients had significantly better results with respect to visual acuity 108,110.…”

Changes in higher order aberrations after central corneal regularization - a comparative two-year analysis of a semi-automated topography-guided photorefractive keratectomy combined with corneal cross-linking

“…Keratoconus patients with a minimal corneal thickness of 400 μm were offered CXL in case of confirmed disease progression. Keratoconus progression was defined as consistent change in at least one of the two following parameters during the previous 12 months: an increase in the steepest keratometry value (Kmax) of ≥1 D [8][9][10][11][12] and/or a decrease in minimal corneal thickness of ≥10 μm [13,14].…”