As we age, our senses become impaired. For example, we experience declines in our ability to see well. In my case, I have recently experienced a decline in my ability to see up close after having been near-sighted since childhood. I just started wearing my first pair of bifocals a year ago at the age of 41. Loss of visual acuity may seem less of a problem than other ailments we acquire as we age, but it is not. Research has established that uncorrectable or uncorrected visual impairment is related to our mental and physical health status. For example, lower visual acuity has been found to be related to cognitive impairment, frailty, functional decline, depression, and poorer self-rated health. One study found that self-reported visual impairment is the third most disabling condition behind cerebrovascular disease and hip fracture. And, a more recent study found poor vision in older adults to affect overall mental health more severely than stroke or heart attack.
In addition to poorer mental and physical health status, individual’s general well-being can suffer from poor vision. Studies have shown visual impairment is related to social isolation, impaired activities of daily living, increased dependency on others, and overall reduced quality of life. And, the risk of traffic accidents and falls and fractures increases as our vision worsens. Ultimately, visual impairment is associated with reduced survival with those experiencing worse vision having a higher risk of death. This association with mortality has been found in many population based studies.
Our research team has been looking into these associations for more than 10 years trying to assess both the severity of the impact that vision loss has for aging adults as well as determining how to minimize the negative effects of declining vision. Often these studies are limited because available data lack objective, clinical measures of visual acuity and/or they do not follow the same individuals over time. However, our recent work has taken advantage of the Salisbury Eye Evaluation (SEE) Study, which followed 2,520 adults age 65 and older over a 10 year period. Using these data allowed us to not only evaluate static associations between visual impairment and health; it also allowed us to evaluate how changes in visual acuity during the aging process relate to changes in other health conditions and ultimately how these changes relate to the risk of death.
In the SEE study, we found that, on average, older individuals are losing the ability to read an additional letter on a visual acuity chart every year, which is equivalent to losing one line of letters every 5 years. Those who experience this degree of decline in their ability to see increase their risk of death by 4% every year. This is after considering most of the other health conditions that are encountered during aging. However, is this association of declining vision ability directly responsible for the increase in risk of death? This was a major question that we sought to answer in our study. Other health conditions may also be in decline at the same time and perhaps changes in vision are impacting these other health processes.
One aspect of our lives that is also changing is our ability to keep up with activities of daily living. This includes activities like doing light and/or heavy house or yard work, making meals, managing money, and shopping for necessities. In our study, we found that individuals have increased difficulty performing basic daily activities as they age and these increases were associated with worsening vision and with increased mortality. Therefore, we hypothesized that declines in the ability to see, result in declines in the ability to perform daily activities, and this is the underlying reason for the relationship between vision declines and mortality. This hypothesis was supported in our study. When we considered the decline in daily activity resulting directly from declines in ability to see, we found that vision decline did not affect mortality by itself, but only through activity declines. Specifically, study participants experiencing the average decline in visual acuity per year were found to have a 16% increase in mortality risk over the 8 year study exclusively through declines in activities of daily living.
The important message from our research is that it is important to keep up with vision care as we age. Make sure that vision problems that can be corrected with glasses or contacts are corrected, and eye diseases that affect vision are treated in a timely manner. And for those of us who experience vision declines that are not easily corrected with glasses or other interventions, it is very important to try to retain robust activities in our daily life, and to remain physically and psychologically active. Doing this will extend our life as well as improve the quality of our life. Our research team also feels that further investments in vision and health, including research are necessary to continue to improve quality of life as we age.
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