Presbyopia onset affects dynamic visual acuity via motor adaptation in naturalistic viewing conditions

Abstract This study investigated how age affects dynamic visual acuity (DVA) and its visuomotor correlates during a high-acuity real-world visual task, focusing on the roles of motor coordination and binocular mechanisms around the onset of presbyopia. Sixty-three participants, ranging from young and adult non-presbyopes to presbyopia-onset individuals and older presbyopes, performed a smartphone-based DVA test while sitting, standing, and walking. The participants’ visuomotor profile was assessed by 8 vergence and accommodation metrics along with 8 motor variables related to smartphone positioning relative to the head. Findings revealed a significant age-related decline in DVA, with the sharpest drop occurring at presbyopia onset. This decline was closely linked to reduced visual accommodation, while vergence had minimal influence. Motor variables, particularly smartphone distance and its antero-posterior and lateral movements, showed a stronger overall impact on DVA. The results suggest that diminished motor adaptation and age-related accommodative changes jointly contribute to the deterioration of DVA during presbyopia onset. Competing Interest Statement The authors have declared no competing interest. Funding Statement Essilor Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ile-de-France VII Personal Protection Committee I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Footnotes ↵* Shared last authorship This version of the manuscript has been revised to update the figures, shorten the overall text. Data Availability All data produced in the present study are available upon reasonable request to the authors