Reframing Anterior Segment Depth: A Scoping Review of Virtual ACD and Related Biometric Parameters for ELP Prediction

Purpose: To map and standardize the terminology used to describe anterior segment biometric parameters related to postoperative anterior chamber depth (ACD)/ effective lens position (ELP) prediction and intraocular lens (IOL) position. Design: Scoping review Methods: A scoping review was conducted following PRISMA-ScR guidelines. Studies reporting definitions, preoperative and postoperative changes, or estimation models of anterior segment biometric parameters related to postoperative ACD or IOL position were included. Parameters were classified according to their anatomical reference into axial, horizontal and combined measurements. Changes from pre to postoperative measures were entered into a standardized evidence table. A qualitative comparative synthesis was used to identify standardized terminology, highlighting consistent findings across definitions. Results: 114 records were selected for full text review. 72 articles were excluded, 22 articles were considered for definitions and 20 articles were considered for definitions and/or data extraction. Substantial heterogeneity in terminology was identified, with multiple definitions describing the same anatomical construct and different measurements sharing identical definitions. Conventional ACD showed marked postoperative deepening, whereas deep anterior segment parameters demonstrated minimal postoperative change, suggesting greater anatomical stability. Conclusion: Anterior segment biometric terminology related to postoperative ACD estimation is highly heterogeneous. The concept of virtual anterior chamber depth provides a unifying and anatomically grounded framework to standardize existing measurements without introducing additional terminology.