Abstract / Summary
Phacoemulsification is the primary surgery for sight restoration. However, in patients with shallow anterior chambers (AC), postoperative refraction often differs from prediction. Anterior chamber depth (ACD) strongly influences effective lens position (ELP), yet, its definition lacks consensus. Moreover, ACD varies due to systemic and ocular factors, which is commonly overlooked preoperatively. There is currently a lack of evidence-based, widely accepted methodology for standardized ACD biometric measurement, highlighting a gap in clinical practice. This study conducted a non-systematic literature search for publications up to August 2026, limiting language to English and Chinese. Based on predefined inclusion criteria, we critically evaluated and selectively included classic conceptual articles defining ACD, as well as studies on factors influencing ACD and biometric measurements. There is still controversy over the definition of ACD in both clinical practice and scientific research. ACD varies dynamically with systemic conditions such as age, diabetes mellitus, and even ethnic variations in anterior segment morphology. Older age, short axial length, and thickened lens are reported to be the main determinants of shallow AC, but this relationship exhibits a stage-specific pattern. ACD measurement techniques are continuously evolving toward greater objectivity, higher precision, non-contact operation, and ease of use. Nevertheless, inter-technique variability persists, not only in physical principles but also in quantitative values. This study indicates that the definition of ACD should be determined based on the specific research context, objectives, and experimental design. The choice of measurement plane should be based on actual anatomical features (e.g., surgical practice) or practical requirements in optical applications (e.g., intraocular lens power calculation). For patients with a shallow AC, clinical evaluation should systematically integrate their systemic condition with ocular characteristics, carefully distinguishing the subtle boundaries between physiological variation and pathological change. As discrepancies persist across measurement techniques, measurement results from different devices are not be interchanged. Based on the ocular characteristics and examination objectives, choosing the appropriate measurement method is crucial.