Moorfields Eye Hospital UCL

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1. Device

Schwind MS-39

2. Number of visits

Notes

Progression criteria

Progression analysis implements the Global Consensus Criteria (Gomes et al., 2015) by evaluating change relative to adaptive measurement repeatability (Balal et al., 2025) which account for disease severity. Changes that do not exceed repeatability limits are considered consistent with expected measurement variability and are not classified as true progression. Keratoconus metrics are evaluated across three categories: anterior curvature (front Kmax, K1, K2), posterior curvature (back Kmax, K1, K2), and minimum pachymetry. A category is classified as progressed if any metric within it exceeds its respective threshold. Overall progression status is defined as:

  • Definite Progression: ≥ 2 of 3 categories show progression

Artificial Intelligence (AI) Risk Calculator Methodology

The AI risk calculator integrates machine learning–derived feature importance with longitudinal tomographic data to estimate the individualised probability of keratoconus progression. The model was trained using a large, multicentre dataset incorporating imaging and tabular parameters, with progression labels defined according to adaptive precision limits and global consensus criteria. From the full feature set, the most predictive variables were selected using systematic feature ablation and importance ranking, ensuring optimal balance between model performance and clinical interpretability. These variables are standardised and processed through a supervised learning framework that outputs a calibrated risk probability for progression within a two-year (MS39) or three-year (Pentacam) time horizon. Model training employed cross-validation, class imbalance correction, and regularisation techniques to minimise overfitting and enhance generalisability. Risk outputs are mapped to clinically meaningful categories aligned with established progression thresholds, enabling integration with conventional progression analysis and supporting risk-stratified clinical decision-making (Balal et al., 2026).

References

  • Gomes JA, Tan D, Rapuano CJ, et al. Global Consensus on Keratoconus and Ectatic Diseases. Cornea. 2015;34(4):359–369. (doi:10.1097/ico.0000000000000408)
  • Balal S, Cai DY, Kandakji ML, et al. Establishing the ground truth for keratoconus progression: combining repeated measures and adapting precision limits to disease severity. Journal of Cataract and Refractive Surgery. 2025;51(9). (doi:10.1097/j.jcrs.0000000000001692)
  • Balal S, Cai DY, Kandakji ML, et al. Automated triage for new keratoconus referrals using multimodal deep learning. Ophthalmology Science 2026.

Acknowledgements

This research is supported by:

  • European Society of Cataract and Refractive Surgeons Digital Research Award
  • Frost Trust Charity
  • Moorfields Eye Charity
  • National Institute for Health Research (NIHR) AI Award
  • NIHR Doctoral Fellowship Award
  • NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust