Interpupillary Distance and Binocular Vision: Assessing the Association Between Anatomy and Sensory-Motor Functions

Background/Objectives: This study aimed to examine how interpupillary distance (IPD) influences motor and sensory binocular vision functions at distance and near, and to examine associations between different motor and sensory binocular vision functions. Methods: A descriptive cross-sectional study was performed involving 100 random participants of both genders, aged 20 to 38 years. Optically corrected and non-strabismic participants were selected from King Saud University, Riyadh, Saudi Arabia between June 2024 and June 2025. Distance and near IPD were assessed with a pupillometer. Motor binocular functions included horizontal phoria using the von Graefe technique and near point of convergence (NPC). Sensory binocular vision was assessed using crossed and uncrossed TNO and Random-dot E stereopsis tests at near and distance respectively. Statistical analysis was conducted using SPSS version 26 (p ≤ 0.05). Results: IPD and phoria were not significantly associated at distance or near. However, moderate and significant correlations were found between IPD (distance and near) and NPC. Significant correlations were also found between IPD and both crossed and uncrossed stereopsis at distance, but correlations were weak or non-significant at near. A strong correlation was observed between NPC and stereopsis at distance. Conclusions: As interpupillary distance (IPD)increases, near point of convergence (NPC) receded, and stereopsis at distance declined, suggesting that anatomical variation influences binocular vision primarily at distance.