Alzheimer’s and the Senses Part Two: Sight

My friends in high school nicknamed me “Eagle Eyes” because I had fantastic long distance eyesight. Now, almost seventy, I wear glasses, and my ophthalmologist told me that I have the beginnings of a cataract.  September eyesight 58345D779A

This is not so unusual. By age seventy, fewer than thirty percent of elderly people have 20/20 vision. According to the University of Michigan’s W. K. Kellogg Eye Center website, ninety percent of people over sixty-five have a cataract, and fifty percent of people between seventy-five and eighty-five have some vision loss due to cataracts.

There are several signs that our eyes are losing some sight. These include: changes in our ability to read and recognize people, difficulty in finding things or locating food on our plate, falling more, becoming hesitant when approaching curbs or stairs, and being startled by persons approaching us from the side.

Sight loss evolves from four conditions:

  1. Normal aging;
  2. Eye conditions such as macular degeneration, glaucoma, and cataracts;
  3. Health conditions, such as a stroke or retinal complications from diabetes;
  4. Dementias that may have a direct impact: Alzheimer’s, vascular dementia, Lewy Body dementia, and posterior cortical atrophy.

    Four Types of Vision

    Four Types of Vision

Seeing is a complicated process. Our eyes do not actually “see.” They act like a camera, transmitting information to the brain to interpret alongside information from our other senses, thoughts, and memories.

With Alzheimer’s disease this interpretation process becomes altered. Even though the information being transmitted remains the same, and the eyes and optic nerve suffer no injury, the brain will no longer process the information in the same way. Unfortunately, more than sixty percent of individuals with Alzheimer’s will have a decline in some sort of visual capacity.

Sight loss can contribute to increased confusion in persons with dementia. They are more vulnerable to falling. Their field of vision also shrinks. Dementia trainer Teepa Snow has an excellent video describing the visual perception range of a person with dementia. (See the resource below this article.) To get an idea how vision loss impacts a person in the mid-stages of the disease, take a ruler and hold it in front of your face horizontally and then vertically. This is their range for vision of approximately twelve-inches in diameter.

Diminishment in eyesight for a person with Alzheimer’s can occur in five areas. Let’s take a closer “look” at each of these, and what you might do to provide some help. These ideas come primarily from the Alzheimer’s Association, Central Ohio Chapter.

Area 1: Depth Perception

If there is damage to the right parietal lobe then the person might have problems with judging distances in three dimensions. Three dimensional or two-dimensional objects appear flat or as shadows. A black or dark door mat or rug may give the perception that there is a large hole in front of the doorway. Navigating stairs is a common difficulty. The person cannot distinguish curbs or steps. They have difficulty seeing water in a glass, or even the glass itself. Shiny flooring appears wet or slippery.

How you can help: Provide extra lighting where possible. Increase wattage of light bulbs. Reduce glare inside the home by pulling down shades when it is particularly sunny outside. Cover glass surfaces on tables. Close curtains or blinds at night. Alert them to curbs and number of steps or stairs when walking.

Area 2: Motion Blindness

The person with dementia is unable to sense movement. Their world is a series of “still frames,” and not a “movie” that most of us see. Part of the brain is damaged in the areas that receive signals from their peripheral vision. Some researchers believe this may account for why people with dementia can become lost, even in familiar surroundings. They can’t see where they are going or retain the memory of familiar landmarks. They can’t see anything except straight ahead without making a conscious effort to move their head instead of their eyes to see. They may also put things down and not be able to see or remember where they put them if they don’t move their heads.

How you can help: When you are out walking together, offer guidance and support. Offer your arm or take their hand if they will let you lead them. Alert them to upcoming sloping areas, steps or curbs. At home, keep a clutter free environment in walkways and hallways to avoid tripping hazards. At mealtimes, describe the food and drink, where it is on the table, and who and what condiments are beside or nearby your loved one.

Area 3: Color Perception

In aging eyes the lens yellow a bit and filter out blue light. Colors often appear faded or washed out, especially colors in the blue-violet range. Blacks and dark blues are particularly difficult to tell apart without bringing items into a bright light. The retina has more receptors to see “red,” which makes this color easier for most people to see.

How you can help: Color contrast is an important element. If possible, serve light food on a dark plate and dark food on a light plate. Serving mashed potatoes on a red plate rather white plate can make it easier to see. Serve drinks especially water in a distinctive color of glass. Put coffee in a white cup as opposed to a dark one. Painting a baseboard a contrasting color from the wall can help the person distinguish where the wall ends and the floor begins.

Area 4: Contrast Sensitivity

The ability to see a shade of gray on a white background or to see white on a light gray background declines with age. Eye specialists routinely test eyes for visual acuity, but contrast sensitivity testing often isn’t included in a routine eye exam. This test measures one’s ability to distinguish between finer and finer increments of light versus dark (contrast), the ability to see items that may not be outlined clearly, and items that do not stand out from their background. The Pelli-Robson chart is one of the most widely used devices to test contrast sensitivity.

Pelli-Robson Contrast Sensitivity Chart

Pelli-Robson Contrast Sensitivity Chart

A person with low contrast sensitivity may also have trouble seeing traffic lights or cars at night,  spots on clothes or other items, a flame burning on a stove, or misses facial gestures. Poor contrast sensitivity also increases the risk of falling when a person needs to step down from a curb or stair onto similarly colored pavement or flooring.

How you can help: Arrange for regular eye checks and a test for contrast sensitivity. Inform the optometrist your loved one has dementia so this can be taken into consideration when arranging for appointments or treatment. Eye glasses with specially designed yellow-tinted lenses can improve contrast. Improve lighting levels in the home, especially bright light for reading. A white toilet seat against a white wall may make it more difficult for the person with dementia to tell where to sit. Consider replacing the seat with a red one. Place contrasting colored rugs in front of doors and steps to help the person with dementia anticipate stairs and entrances. White or yellow borders on the edges of steps may also help.

Area 5: Visual Agnosia and Misidentifications

Agnosia is the loss of ability to recognize what objects are and what they are used for. A person with dementia may see a fork or a spoon but not remember what it is used for or how to hold it.

Agnosia is also the inability to recognize who people are. For example, they may be unable to distinguish the difference between their husband, son, or brother.

University of Montreal researcher Dr. Sven Joubert, Ph.D., conducted a study regarding the ability of persons with Alzheimer’s to perceive faces and cars. The results indicated that the brain must perform a local analysis of the various image components perceived by the eye. The study confirmed that Alzheimer’s disease impairs visual face perception.

How you can help: Try to imagine a person’s fear looking at a loved one and not recognizing him or her. Move yourself into the person’s visual field before you start to communicate or care for them. Get their attention by identifying yourself. This is a cue, especially if you are visiting and they haven’t seen you for awhile. I used to greet my mother in the nursing facility by saying, “Hi, Mom! It’s me, Vicki, your daughter.”

The latest research from two studies regarding early identification of cognitive dysfunction was presented at the Alzheimer’s Association International Conference in July. These studies showed that thinning of the retinal nerve and protein deposits in the eye could be used to detect early signs of dementia. Amyloid protein found in the brains of persons with Alzheimer’s can also accumulate in the retina. Perhaps in the near future a simple eye test will become a relatively easy, non-invasive way to spot cognitive changes early on.

Understanding potential eyesight problems, along with your efforts to help optimize the sense of sight in your loved one, will surely maximize their quality of life, help them retain their independence longer, reduce risk of falls and injuries, and provide reassurance at a time when the way they perceive reality may be changing.

I wish you peace, patience, and joy in your caregiving today and every day!

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Teepa Snow, dementia care expert and trainer, describes how the visual field of a person with dementia changes in this short video: https://youtu.be/NCCK-UDhXag.

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This video examines the “Emotional Aspects of Vision Loss,” by Dr. Sandra Fox, OD: http://training.mmlearn.org/video-library/emotional-aspects-of-vision-loss.

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For information about dry and wet age-related macular degeneration and other eye conditions, visit the website of the American Academy of Opthalmology: http://www.aao.org/eye-health.

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Put yourself in the shoes of Joe’s Mom, a woman living with dementia, in this three-minute video, “A Walk through Dementia,” produced by Alzheimer’s Research UK: https://youtu.be/R-Rcbj_qR4g.

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To read about Dr. Joubert’s study of visual face perception check out: http://j-alz.com/content/why-do-people-alzheimers-stop-recognizing-their-loved-ones.

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This four-minute Ted-Ed video examines the science behind night vision comparing our human eyes to those of other creatures: https://youtu.be/t3CjTU7TaNA?list=PLJicmE8fK0EiEzttYMD1zYkT-SmNf323z.

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If you found this blog beneficial, please share it with others to spread the information. Also “like” us on our Facebook page: https://www.facebook.com/CaregiverFamilies/.

 

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