Development and Validation of the Relational Tissue Altered (RTA) Index: Applied Artificial Intelligence for the Assessment of Structural Impact from Laser Vision Correction

The Relational Tissue Altered (RTA) index provides an objective and data-driven measure of the structural impact induced by laser vision correction (LVC) on the cornea. Compared with traditional parameters such as Residual Stromal Bed (RSB) and Percent Tissue Altered (PTA), which were not originally designed to quantify biomechanical disruption, RTA demonstrated superior performance in characterizing surgical impact. Although not developed as a standalone ectasia predictor, RTA offers unique value when integrated with preoperative assessments of intrinsic corneal susceptibility, including topometric, tomographic, and biomechanical metrics. This synergistic approach holds promise for enhancing risk stratification, refining surgical planning, and advancing the safety and personalization of refractive surgery.