PURPOSE: We studied effects of age and horizontal duction on deformation of the optic nerve (ON) head and peripapillary retina as reflected by displacement of vascular landmarks to explore the influence of adduction tethering. DESIGN: Cross-sectional study. METHODS: Setting: University. Study Population: Single eyes of 20 healthy young adults (average age 23.9±3.9 SD) years were compared to 20 older subjects (average age 61.4±9.3) years. Observational Procedure: The disc and peripapillary retina were imaged by scanning laser ophthalmoscopy in central gaze, and 35° abd- and adduction. Main Outcome Measure: Deformations of the disc and adjacent PPR were measured by comparing positions of epipapillary and epiretinal blood vessels. RESULTS: Vessels within the ONH of younger subjects shifted temporally during adduction and nasally during abduction. Displacement of the nasal hemi-disc in adduction was greater at 38.5±1.7μm (SEM) than the temporal half at 4.1±2.1μm (P