As we grow up and grow old, our visual needs and our visual capabilities both change. Developmental vision is about enabling patients to use their vision to perform a myriad of activities across the life span. For a 7 year old, the focus may be on academic performance or playing soccer. For a 70 year old, the focus might be on navigating through the environment safely–without falling. Dr. David Elliott received an award from the American Academy of Optometry for his research into the relationship between blurred vision, spectacles and falls in older adults.
Many falls are not random events. They are linked to a wide range of risk factors, both intrinsic and extrinsic. It is easy to understand the importance of vision, especially when confronted by abrupt changes in the environment such as steps, stairs and curbs. Reduced vision may be caused by normal aging changes or ocular pathology; but it might also be attributed to the need for something as simple as a new eyeglass prescription. Many studies have shown that reduced vision is a risk factor for falls; however optometric intervention and cataract surgery have not shown the reduction in falls rate that might have been expected. In fact, large changes in refractive status seem to increase the risk of falls, even if visual acuity improves.
Large changes in a lens prescription may cause large changes in visual perception. Objects may appear closer or further away than they really are; they may even appear to move when the head and eyes move. Surfaces such as walls and floors may appear sloping or slanted. Until these patient can adapt and recalibrate, they are at increased risk for falls. Perhaps most significant, these risks are greater if the patient is changing from single vision to bifocal lenses. Objects in the lower visual field will be blurred when viewed through a bifocal; peripheral vision is reduced and sometimes distorted; objects may appear to jump. The degree of these effects is dependent upon the power and type of bifocal.
Dr. Elliott offers these recommendations:
- Identify patients who may be at high risk for falls.
- Be conservative when changing the prescription, especially the astigmatic correction.
- If at all possible, do not change the bifocal type.
- Educate patients about changes in perceptions and advise extra caution while adapting to new spectacles.
- Some patients may benefit from a separate pair of single vision glasses to be worn outside the home.
What is the take-home message here? Developmental vision is a philosophy of vision care that is not just about kids! Optometrists can have a major impact on the health and safety and performance of their older patients beginning with careful consideration of their spectacle prescriptions. And that’s just the beginning!