Alpins vector analysis for the evaluation of astigmatic correction following SMILE Pro surgery using the VISUMAX 800

Abstract

Purpose: To evaluate astigmatism treatment outcomes of the VisuMax 800 femtosecond laser system in SMILE Pro surgery using comprehensive Alpins vector analysis. Methods: A prospective descriptive study of 80 eyes (40 patients) undergoing SMILE Pro at Saigon Eye Hospital Ngo Gia Tu from December 2024 to September 2025. Alpins vector analysis was performed on 74 eyes with TIA ≥0.25 D using AstigMATIC software; standardised outcome charts were generated using Meyestro software. Results: Mean TIA 1.00±0.53 D; SIA 0.98±0.51 D; DV 0.08±0.03 D; CI 0.94±0.02; R²=0.97 (y=0.94x+0.05). In 99% of eyes |AOE| ≤5°; 100% had DV ≤0.5 D. At 3 months, 95% of eyes achieved residual astigmatism ≤0.25 D and 100% ≤0.50 D. Conclusions: SMILE Pro with the VisuMax 800 demonstrated measurable astigmatism correction accuracy by Alpins vector analysis: CI=0.94±0.02; DV=0.08±0.03 D; AOE=0.06±1.60° (99% within ±5°); R²=0.97. Outcomes showed improvement over previous-generation SMILE, with the OcuLign cyclotorsion compensation system playing an important role in axial accuracy.