Masi: A Rapid, Objective Metric For Evaluating Klex Outcomes And Visual Quality
Published 2025 - 43rd Congress of the ESCRS
Reference: FP16.15 | Type: Free paper | DOI: 10.82333/x6kq-at15
Authors: Erika Bonacci 1 , Emilio Pedrotti* 2 , Francesca Barzaghi 2 , Giorgio Marchini 2
1Department of Engineering for Innovation Medicine, Ophthalmology Clinic, University of Verona, Italy,University of Verona,verona,Italy, 2Ophthalmology Clinic, Department of Surgery, Dentistry, Maternity and Infant, University of Verona, Verona, Italy ,University of Verona,verona,Italy
Purpose
To introduce and validate the Micro Aberration Scatter Index (MASI) as a fast, objective measure for assessing quality of vision in keratorefractive surgery, with a particular focus on kerato-lenticule extraction (KLEx) outcomes.
Setting
Eye Clinc Svjetlost, Zagreb, Croatia
Methods
Eighty-four post-KLEx eyes underwent a comprehensive evaluation including conventional visual acuity (VA), higher-order aberrations (HOAs), mesopic pupil size, and contrast sensitivity function (CSF) at multiple spatial frequencies (cycles per degree, CPD). MASI values were derived from wavefront gradients to quantify micro-aberration–induced scatter. Correlation analyses, linear and multivariate regressions, and non-linear (random forest) models were performed to compare MASI with existing predictors of visual quality, such as HOAs, CPD, and spherical equivalent (SEQ).
Results
MASI values showed a strong inverse relationship with CPD, indicating that eyes with lower scatter demonstrated higher contrast sensitivity. Regression and random forest models confirmed MASI as a significant predictor of visual performance, correlating negatively with VA logMAR (i.e., better visual acuity with lower MASI). Cluster analyses suggested MASI effectively differentiated subgroups with varying degrees of post-KLEx optical quality. By replacing conventional contrast sensitivity testing—which can be lengthy and patient-dependent—MASI yields comparable insights in a fraction of the time, potentially saving up to 20 minutes per eye (or two weeks of clinical time for 1000 eyes).
Conclusions
MASI provides a rapid, objective, and reproducible metric for evaluating post-KLEx optical quality and predicting visual outcomes. Its strong correlations with HOAs and CSF metrics, along with substantial time savings, make MASI an attractive alternative or adjunct to traditional contrast sensitivity tests. By streamlining patient throughput and offering robust data comparability across clinics and surgeons, MASI has significant potential to improve both the efficiency and accuracy of keratorefractive outcome tracking.