Predicting factors for the efficacy of cross-linking for keratoconus

Abstract

Purpose To evaluate predictors for success in corneal crosslinking (CXL) for keratoconus in a large cohort and extended follow-up. Design A retrospective study based on a prospectively built database. Methods Participants underwent CXL for keratoconus from 2007 to 2018. Statistical analysis was performed for patients with at least 1-year follow-up. We analyzed effects of CXL type (Epithelium-on or Epithelium-off and Accelerated (9mW/cm2@10min) or Standard (3mW/cm2@30min)) and pre-operative factors including age, gender, baseline LogMAR visual acuity (LogMARpre), maximal corneal power (Kmaxpre), pachymetry, refractive and topographic cylinders, spherical equivalent (SEpre), mean corneal power (MeanK) and follow-up time on outcome measures. The outcome measures were the final change of Kmax (Delta Kmax) and the final change in LogMAR visual acuity (Delta LogMAR). A more negative Delta Kmax or Delta LogMAR represents a favorable effect of crosslinking. Results 517 eyes had Kmax results, and 385 eyes had LogMAR results with more than one year follow-up. These eyes were included in the study. The mean follow-up time was 2.29 years. Mean Kmax decreased from 54.07±5.99 diopters to 52.84±5.66 diopters (p<0.001), and Mean LogMAR decreased from 0.28±0.20 to 0.25±0.21 (p<0.001). Non-accelerated epithelium-off CXL resulted in greater flattening of Kmax when compared with other protocols. Visual acuity improvement was similar when comparing different CXL protocols. Multivariate analysis showed four factors associated with negative Delta Kmax: high Kmaxpre, high SEpre, high MeanKpre, and non-accelerated procedure. Multivariate analysis showed three factors associated with negative Delta LogMAR: high LogMARpre, high SEpre, and Low MeanKpre. After excluding corneas with Kmaxpre >65 D or Pachymetry<400 microns, multivariate analysis showed that high Kmaxpre, high SEpre, and non-accelerated CXL were associated with negative Delta Kmax while high LogMARpre and high SEpre were associated with negative Delta LogMAR. Conclusion CXL for keratoconus is a highly effective treatment, as evident by its effects on the outcome measures: Delta Kmax and Delta LogMAR. CXL was more successful in eyes with high Kmaxpre, high SEpre, and high LogMARpre, which express disease severity. The non-accelerated epithelium-off protocol was associated with greater flattening of corneal curvature but did not show a better effect on visual acuity as compared to the other CXL protocols.

Unravelling the Impact of Cyclic Mechanical Stretch in Keratoconus—A Transcriptomic Profiling Study

“…Keratoconus (KC) is one of the most common corneal ectasia and a leading indicator of corneal transplantation worldwide [ 1 , 2 , 3 , 4 ]. It’s defined by the gradual thinning and steepening of the typical dome-shaped cornea into a cone-shaped form, resulting in intensified irregular astigmatism, myopia, increased corneal sensitivity, and a decrease in visual acuity [ 5 , 6 , 7 ]. It generally begins in adolescence, lasts 10–20 years, and then stabilizes in the third or fourth decade of a person’s life [ 8 , 9 ].…”

Ultra-High Resolution Optical Aberrometry in Patients with Keratoconus: A Cross-Sectional Study

“…Elevation maps from corneal topography have been reported as sensitive screening methods, even in early-stage KC or forme fruste [9], furthermore new technology applied to those maps could improve the detection of the disease [10]. The point of maximal corneal elevation measured in diopters (Kmax) and the minimum value of the pachymetry map (PKmin) are two accurate and widely used indicators of KC progression [11][12][13], although more recent publications suggest that combinations of corneal parameters could be even more precise due to their high repeatability [13,14]. Novel devices combining tomography and air-puff response that have been developed to measure the biomechanical properties of the cornea are promising but lag far behind other systems of KC detection and progression assessment on the basis of previous technology [15].…”