ORCID
- Daniela Oehring: 0000-0003-2954-0548
Abstract
PurposeTo compare regional biomechanical and topographic outcomes between transepithelial (Epi-on) and epithelium-off (Epi-off) continuous accelerated corneal cross-linking (ACXL) in keratoconus.DesignRetrospective cohort study.Subjects77 keratoconic eyes were included: 45 with Epi-on ACXL and 32 with Epi-off ACXL.MethodsAll eyes underwent ACXL (10 mW/cm2, 7.2 J/cm2). Pentacam HR and Corvis ST measurements were obtained preoperatively (pre), and at 1 month (pos1m), and 6 months (pos6m) postoperatively. The SSIv2m, M, and J0, J45 were evaluated across central (0–3 mm), paracentral (3–6 mm), and peripheral (6–9 mm) regions. Correlated measurements were analyzed using generalized estimating equations (GEE) for regional and longitudinal data, and generalized linear models (GLM) for inter-group comparisons, with both absolute (Δ) and relative changes (Δ%) evaluated.Main Outcome MeasuresRegional changes in SSIv2m, M, J0, and J45 were analyzed across central (0–3 mm), paracentral (3–6 mm), and peripheral (6–9 mm) regions preoperatively and at 1 and 6 months postoperatively.ResultsAt 6 months, SSIv2m increased significantly in all regions of the Epi-off ACXL group (greatest centrally), whereas the Epi-on group showed no consistent change. ΔSSIv2m between pre and pos6m was significantly greater in Epi-off ACXL than Epi-on ACXL across all regions (all P < 0.05). Central flattening (negative ΔM) was significant in the Epi-off ACXL group (P < 0.001) and exceeded that in Epi-on ACXL (P < 0.001). No significant changes were detected in J0 or J45. Δ%SSIv2m exceeded Δ%M in the paracentral and peripheral (all P < 0.05) regions after Epi-off ACXL.ConclusionsEpi-off ACXL induces stronger and more durable biomechanical stiffening and central flattening than Epi-on ACXL. Biomechanical parameters, particularly SSIv2, were more sensitive than curvature-based metrics for detecting regional treatment effects.
DOI Link
Publication Date
2026-05-24
Publication Title
Ophthalmology Science
Deposit Date
2026-05-28
Funding
This research was supported by the National Natural Science Foundation of China (82271049) and the Projects of Medical and Health Science Technology Program in Zhejiang Province (WKJ-ZJ-2542).
Keywords
keratoconus, corneal cross-linking, ocular biomechanics, corneal shape, regional variation
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Recommended Citation
Mao, B., He, C., Ye, Q., Liu, W., Oehring, D., Li, Y., Zhang, Y., L, X., Zhao, C., Hu, H., Gong, J., Hou, H., Ye, Y., Chen, S., Li, Y., Elsheikh, A., & Bao, F. (2026) 'Regional Biomechanical and Topographic Changes following Epi-on vs Epi-off Continuous ACXL in Keratoconus: SSIv2 as a Superior Biomarker', Ophthalmology Science, . Available at: 10.1016/j.xops.2026.101246
