The fastest growing segment of the US population is people over 80 and more than 80% of them are living independently. Dr. Haegerstrom-Portnoy has been conducting a longterm study (15 years and still going) with a group of elders in Marin to evaluate what happens to vision as we age and has described several functions that are significantly impacted. Below are some of her research results.
One important function that doesn’t decrease is the ability to read an eye chart (and pass that driving test). The problem is, the ‘real world’ doesn’t exist in high contrast like our eye charts; that is, bold black letters against a bright white background.
Contrast sensitivity (the ability to distinguish one shade of grey from a slight lighter or darker shade of grey) drops very rapidly after the age of 65 and by 80 years old is about 18 times worse than a 20 year old. To get a feel for how the world may appear with reduced contrast sensitivity, hold a clear sandwich bag (so two layers of plastic) over a camera lens and then shoot a picture of a sidewalk or a stairway. What you’ll see is that it is much more challenging to read the contours of the sidewalk or stairs.
The ability to recover from bright lights and glare takes significantly longer for this group. A 20-year-old may take 10 seconds to see going from outdoors into a dim room while 80 year old eyes may take 2 minutes. Think of the adaptation you go through when you enter a movie theater during the day and imagine it taking 20 times longer.
Our ability to see in the presence of glare (think driving at night with oncoming headlights, or the glare at sunrise or sunset) is greatly affected by age. Half the people over 80 see only 20/400 (the giant E on our eye chart) in the presence of glare so the glare is truly blinding. She has also reported on more difficulty reading fluently (even though the vision on an eye chart is fine). Recognition of expressions on faces at a distance becomes more challenging and someone over 80 may miss a social cue that a person is angry or sad. There’s also a marked reduction in ‘attention fields’; that is, when driving, the ability to pay attention to the object in front of you while at the same time, attending to, for example, a person crossing the street off to the side.
How can we improve vision function in the elderly, be it parents, our grandparents or ourselves?
- Make sure their glasses are up to date by checking the prescription every two years and changing glasses periodically to replace scratched up lenses. It becomes critical to wear the correct lenses to maximize contrast, which may mean drug store reading glasses may no longer be adequate.
- Increase the lightening in an elder’s home a lot using incandescent rather than fluorescent lighting. (The bluish light of fluorescent light has a harder time reaching the back of an older eye.)
- Make lighting even throughout the house to minimize glare recovery; that is, going from a brightly lit room to a dim hallway with throw rugs is a recipe for a fall, so even out the lighting.
- Improve the contrast of objects against the background in places like stairs by putting bright tape on the edge of a stair. (Use your camera with the sandwich bag to see the difference in being able to judge the drop in a stairway with and without high contrast tape.)
- Wear dark sunglasses and a dark brimmed hat outside to avoid the high intensity light that is hard to recover from.
- Avoid driving at night, sunrise and sunset, the high glare times; and for those of us not in the 80+-year-old range, be more willing to transport elders during those times.
- Know it is more challenging to attend to driving for an older person so if you are a passenger, you may not want to chit chat but actually help scan for pedestrians, etc. (And if you are crossing the street, don’t assume that driver sees you!)
- Be patient with yourselves and elders.
The results of this study are based on averages and there is a tremendous variability from individual to individual, so asking anyone over 80 to restrict their driving would be unreasonable (the inability to drive in most communities is very isolating), but some introspection for those people in that age range about how well their vision functions would be useful, as well as feedback and willingness to help out from the younger generations.