SESSION 1: Your Health and Your

Health and Driving Performance

Of the thousands of seniors who completed this course in a classroom setting, most felt uncomfortable talking about the physical changes and losses associated with aging. While aging is a universal fact of human existence, it affects each of us differently. We each have our own ways of adjusting to, compensating for, and making peace with these variations. The section about health comes first in this text because it is so important that every driver recognize common changes in physical condition and their impact on driving performance. Although this section relies on a great deal of scientific research, it can only cover general facts. You individual medical practitioner is the authoritative source of information on your personal medical situation. This material gives an overview of the mental and physical changes that often accompany aging.

REFLEXES BECOME SLOWER AS YOU AGE.

Heres a little test you can take to determine your own reaction time. Get a watch with a second hand. There are 12 numbers in the blocks below. When the second reaches 12 oclock, touch each number AS FAST AS YOU CAN -- IN ORDER from one to twelve. Time yourself and check -your results.

Okay. How did you do?

If you completed all 12 touches IN ORDER in five or six seconds - your reaction time is EXCELLENT.

If you needed seven to nine seconds, your reflexes are still PRETTY GOOD.

If you needed ten or more seconds, your reflexes have slowed. You can probably still drive safely, but BE AWARE that it may take you longer to react than is optimal and that you need to compensate for this slippage.

This activity is not entirely conclusive. Consider it a general guide to your reaction capabilities.

So, what are some of the health problems we all can expect?

Some of the physical changes associated with aging are hard to miss. We might say theyre right before our EYES.

Cone (Central) vision is the type of eyesight used to focus on objects and comprises only about THREE degrees of our entire field of vision. As you read these words, notice how the room beyond the page blurs as your eye scans each word. You only really see whats in your immediate frame of view. This same phenomenon occurs when you drive, walk, push a shopping cart or perform any activity when you focus on one thing to the exclusion of everything else.

Peripheral vision also monitors the environment for movement. The perception of movement or activity attracts our attention, and we move our eyes to determine whats happening. This can be particularly handy when driving. Motion and light catch your eye as you drive, drawing attention to potential hazards. That movement or activity may sense a glint of light from the bumper of a bicycle, the movement of a car about to leave a curb, or a brake light at an intersection drawing your attention to the potential hazard. Without both central and peripheral vision functioning normally, driving becomes extremely dangerous.

When we drive faster than usual, our peripheral vision narrows. When driving at a relaxed pace of 10 MPH, the field of vision can be 180 degrees. When driving at freeway speeds, the field of vision significantly narrows. The periphery closes in due to stress, or increased concentration on the central visual field. Aging reduces peripheral vision.

The Aging Eye

Aging impairs our eyesight in many ways and degrees. Here is a brief description of what problems can occur and how they affect driving:

Impairment of Ocular Transmission

Impaired ocular transmission is a reduction in pupil size that limits the eyes ability to adjust to lower levels of illumination. The effect is an inability to recognize objects and details at dusk, in tunnels, in shaded areas, and at night.

(Have you noticed this lately?)

Glare Threshold and Recovery

This particular limitation occurs in everyone. Glare is temporarily blinding. The older we get, the slower we recover from glare and the more sensitive our eyes become to bright lights. We have all had our pictures taken with a flash and seen residual spots for a period of time. The time it takes for the spots to disappear is what is known as glare recovery time. This effect is serious. After a bright g1are, you may be driving virtually blind until your vision clears. Even if you are traveling at a modest 30 mph and have a one second glare-recovery time, you have traveled 44 feet without being able to see.

Accommodative Convergence Accommodation is the eyes ability to

change focus to see objects clearly at different distances. Presbyopia is a universal condition that occurs after about age 40. The lens of the eye loses flexibility and the ability to focus close-in is lost. With accommodative convergence, the individual has difficulty shifting focus from objects close-up to objects far away. Close objects, such as the dashboard, may be out of focus, but so too may be distant objects (the road ahead). The result is reduced depth of field.

Consider the impact on driving performance. While the eye scans between objects at various distances, the road ahead, the interior mirror, the instrument panel the exterior mirrors, then back to the road again, moments elapse during which the eye is taking too long to shift focus and everything is out of focus. The consequences can be quite serious while driving.

Central Movement in Depth

This is a problem that affects central vision. The brain loses the ability to perceive accurately the changes in image sizes. Since we rely on how big an object looks to tell us how far away it is, this deficit can cause us to misjudge distances. It may become particularly difficult to assess the distance of objects moving away from or approaching us. Following other cars, approaching a busy intersection, and assessing the distances and speeds of oncoming cars become unwelcome challenges. Consider this limitation when you make a left turn into approaching traffic. The other car may be closer than it looks. If your passengers tend to gasp as you make left turns, accept that their eyes may be giving them more accurate information than your own.

Reduced Static and Dynamic Acuity Static acuity is the ability to clearly distinguish the details of a stationary object. Dynamic acuity refers to the ability to see fine details in a moving object. Reductions in static and dynamic acuity can make driving more difficult. Part of the way we judge distance and speed is by how much detail we can see in moving objects, and without that detail our judgment is impaired. At-tempting to read road signs, finding an address, determining if that object in the road is animate or inanimate become major distractions during driving.

Color Perception

As our lenses age, they tend to become slightly yellow. Less light is passed through and there is a gradual loss of brightness. There is also a slight skewing of color perception as the blues and greens become less vivid, especially relative to reds and yellows. Also, studies have shown that color blindness occurs on the blue end of the spectrum and most often in men. This is why men may have trouble with color schemes, matching socks, wearing any color other than tan or brown. If color blindness is a

problem, drivers may have difficulty distinguishing the color of traffic lights and road signs. This is easily compensated by recognizing shapes and locations of traffic signal lights (red on top, yellow in the middle green on the bottom).

Degenerative Eye Conditions

There are three degenerative eye conditions that may be associated with the aging process. These can have profound effects on driving.

Glaucoma

Glaucoma is a very common condition. With glaucoma there is a gradual shrinkage of the visual field beginning in the periphery and moving inward. This loss of vision is caused by an increase in ocular pressure.

Glaucoma makes it especially hard to distinguishing objects and details without adequate illumination. Night driving becomes especially treacherous and should be kept to a minimum. Peripheral vision is affected early in the condition. People with glaucoma may eventually lose their peripheral or side vision and experience an increase in tunnel vision. Accordingly, people with glaucoma must use their mirrors (inside and outside) more often to establish movement around the vehicle to identify potential hazards.

The increased ocular scatter experienced by glaucoma patients also reduces the ability to detect images clearly.

Cataracts

Cataracts are a clouding or opacity of the lens of the eye. Today lens replacement surgery can effectively treat cataracts in most patients. Cataracts reduce contrast in retinal images, diminishing the ability to see low-contrasting images. Driving in crowded areas becomes hazardous because of the difficulty in identifying potential dangers. Driving at night is particularly risky. Disbursed glare from lights causes severe reduction in the ability to see clearly. For those who have never experienced a cataract, it is much like looking through eyeglasses that have been smeared with grease.

Macular degeneration

Macular degeneration is progressive, irreversible damage to the macula, which is part of the retina. It can occur with aging and results in a gradual loss of central vision. It may contribute to blindness. People with this condition lose the ability to see objects in the central portion of the field of vision. The first symptoms of macular degeneration may be a distortion or cloudiness in one small area of central vision; it may look like a spot of white paint on your glasses. Laser surgery can be used to treat some forms of this disease. In the advan