Mobility and Falls
Locomotor strategies are planned using information acquired by intermittent visual sampling of the environment, which means the visual system is free to attend to other things. This highlights that where and when we look are key factors in our ability to safely negotiate changing terrains. It also highlights that visual impairment that results in impoverished information about the environment may lead to the adoption of unsafe locomotion strategies.
How is landing behaviour affected by visual impairment when stepping down?
To understand what, where and how different aspects of visual (and other sensory) information is used to regulate locomotion and posture in various environments and ambient conditions.
- How correctable visual impairment such as refractive blur and cataract effects balance control and movement strategy during stair negotiation
- How multifocal spectacle use effects gait over obstacles and/or during transition to a new level
- How the removal of binocular vision effects movement planning and control
- What peripheral versus central cues are used to plan and control movement
Multifocal lens wearers are twice as likely to fall as single vision lens wearers. This is likely to be because low level objects are out of focus when viewed though the intermediate or near addition part of lens.
In the UK over 2m falls each year result in hospital treatment. Of these, almost 10% of cases are linked to visual impairment, with the majority being elderly individuals 65 yrs and above. It is estimated that up to 80% of this visual impairment is correctable via refractive correction (40%) or cataract removal (37%). Although it is known that visual impairment is a risk factor for falls, little is known about how visual impairment affects postural stability and obstacle & step/stair negotiation. Even when vision is optimally corrected, the use of multifocal spectacles has been linked to increased risk of falls.
Impact Case study on Reducing Trips and Falls in the Elderly.