Many factors contribute to vulnerability to falling, including vision and physical impairments, medications, dementia, progressive lenses and bifocals, and chronic medical conditions such as diabetes, arthritis, obesity, autoimmune disorders, Parkinson's Disease and other neurological conditions.
While physical strength, gait and balance can be improved with physical therapy and exercise, chronic progressive eye diseases that lead to low vision (glaucoma, macular degeneration, retinopathies, inoperable cataracts) are uncorrectable conditions that can't be improved with surgery, medications or lenses, thus making people with these conditions more vulnerable to falling, especially under poor lighting conditions where they have the most difficulty seeing.
Poor vision and poor lighting is an often overlooked risk combination that doubles the chance of falling.
Most falls are caused by a combination of risk factors- the more a person has, the greater the chances of falling.
One of the greatest fears of people with vision loss is being injured by a fall - at home, where half of all falls occur- and away from home in unfamiliar environments. Many people with impaired vision become caught in a downward cycle of fear of falling, which discourages them from leaving home except perhaps for medical appointments. Shopping, walking, exercise classes, social events, vacations and visiting family and friends become increasingly rare outings, leading to an isolated, sedentary lifestyle. Lack of physical activity and mental stimulation in turn leads to weakness and balance impairments, worsening of other medical conditions and depression-all of which increase the risk of falling or falling again.
Many medical and healthcare sites contain important and helpful advice on what can be done to reduce the risk of falling. The Centers for Disease Control (CDC) suggests these basic lifestyle and safety changes to help reduce risk or prevent falls:
-Begin an exercise program to improve your leg strength & balance.
-Ask your doctor or pharmacist to review your medicines.
-Make your home safer by removing clutter and tripping hazards.
-Install railings on all stairs and add grab bars in the bathroom.
-Schedule annual eye check-ups and update your eyeglasses.
-Install good lighting, especially on stairs.
Let's explore the last two recommendations in more detail to explain the links between vision impairment, lighting and falling. Almost all articles advise on how to reduce falls by scheduling regular vision checks and having good environmental lighting, but they don't explain why poor eye health and poor lighting are a dangerous combination for people with vision and mobility impairments.
Diminished Night Vision with Aging
Several natural changes occur in aging eyes that affect otherwise normal vision in low lighting and at night. It is not uncommon for people 40 and older with unimpaired vision during the day to have difficulty seeing well at night. The pupils dilate less and more slowly, allowing less light to reach the retina. The lenses become browner (termed "brunescence"), reducing color perception and acuity (focus). These changes lead to longer times required to acclimate when traveling from light to dark environments, which can even cause temporary blindness until the eyes adjust. Diminished night vision can frequently be corrected with glasses or contact lenses.
Chronic Eye Diseases and Low Vision
The onset of chronic progressive eye diseases - all of which should be diagnosed as early as possible during annual eye exams to manage and slow progression- cause uncorrectable vision loss that interferes with the ability to carry out activities of daily living, and is especially problematic in the dark. In addition to the normal aging processes, these uncorrectable low vision conditions further impair depth perception (3-D vision), color perception, the ability see edges and the ability to judge distances, all of which contribute to make the combination of low light and low vision as a major risk factor for falling. For individuals who also are in poor physical condition and have balance problems, the risk is even greater.
Vision and Light
Simply stated, vision requires light. As the degree of vision impairment and associated effects increases - loss of depth, color and edge perception and ability to judge distances- more light is required to enhance remaining vision to illuminate falling hazards such as steps, curbs, rugs, misplaced shoes, electrical cords, etc. to reduce the risk of falling over these unseen obstacles. Bright, directed (also called task) lighting is best for vision-impaired eyes because it shines directly on the floor or ground in the immediate walking area. The color and quality of light are also important to maximizing visual perception and will be the topic of a future blog.