Document resource
Background/aims To examine the angle between the driver’s eye and the three mirrors (side and rear-view) across different vehicle models, in order to understand head and gaze adjustments that may be necessary for post-strabismus surgery patients to reduce diplopia while driving.Methods The driver’s eye angle (DEA) was defined as the horizontal angle between the driver’s line of sight when looking straight ahead and the direction of their gaze required to view the centre of a given mirror. Angles were measured using a digital protractor from a single 69 inch (1.75 m) tall driver’s eye position to the centre of the three mirrors (left side, right side and rear-view) in each vehicle. Measurements considered seat height and proximity to the steering wheel.Results DEAs were calculated for the seat position deemed most comfortable (CP) by the model driver. For the rear-view mirror, the average CP DEA was 43.5° (range: 35.0°–48.4°). The left side mirror averaged 45.8° (range: 39.3°–52.1°) and the right side mirror 68.9° (range: 63.1°–80.3°). Generally, DEAs were highest with the seat in a forward-high position and lowest when seated further back and lower.Conclusions Patients with strabismus or postsurgical limitations may experience diplopia when using mirrors that require extreme gaze angles. Clinicians should incorporate driving-related visual demands into postoperative counselling. Encouraging rearward-lowered seating and recommending vehicles with narrower mirror angles may reduce symptoms. In some cases, adaptive devices (wide-angle mirrors, blind spot monitoring) may be necessary for safe and comfortable driving.