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

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.

A scoping review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-analyses for Scoping review (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 preoperative 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.

One hundred fourteen 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, highlighting a different anatomical behavior that may be relevant for IOL positioning.

Anterior segment biometric terminology related to postoperative ACD estimation is highly heterogeneous. Virtual anterior chamber depth (ACD) may represent one possible conceptual synthesis and anatomically grounded framework, among other landmark-based approaches, for standardizing existing measurements without introducing additional terminology.