Clinical utility of pupil diameter cutoffs for detecting early presbyopia

PURPOSE: Little data exist on clinically relevant pupil diagnostic values for detecting early presbyopia (accommodative amplitude [AA]< 2.50D). This study aimed to determine the optimal cutoff value of pupil diameters for screening early presbyopia. STUDY DESIGN: Cross-sectional observational study METHODS: 115 individuals aged ≥20 with visual acuity ≥20/25 who had attended one of two healthcare facilities in Japan between December 2020 and December 2021 were included. AA and near and distance pupillary diameters were measured by auto kerato-refractometer (ARK-1s; NIDEK Co.). Optimal cutoff values for early presbyopia were determined by receiver operating characteristic plots based on the Youden index. RESULTS: Among the pupil-related parameters (near or distance alone, or the difference between these), the difference between near and distance pupil diameters of 0.95 mm yielded the best results, with 82.4% sensitivity and 82.9% specificity (AUC 0.87). CONCLUSION: A difference in pupil diameter of 0.95mm could be the optimal cutoff value for assessing early presbyopia. As pupil dynamics have been previously related to presbyopia, this study proposes threshold pupil diameter measurement values to provide an alternative practical way to clinically screen for and assess presbyopia.