My husband wore glasses. And he had Alzheimer’s. And he had a retinal tear that required a laser procedure, which was no fun.

My kids and I thought Morris’s vision was deteriorating because he couldn’t see objects, such as a drinking glass right in front of him. This went on for years. Sometimes he was afraid to walk, thinking he’d fall or run into something. But it wasn’t his vision. The problem was in his brain.

It can be difficult to tell the difference between sight loss and visual problems due to dementia. Often times, one condition can mask the other.

Here’s what I learned.

People with Alzheimer’s and other dementias have visual difficulties caused by what is happening in the brain. They can still have healthy eyes, or have vision that hasn’t changed significantly. Their perception problems are not due to how clearly they see, but to changes in the brain.

Some of these difficulties may indicate dementia. My husband had to deal with almost every one of these issues.

• reading
• recognizing people
• coping with low light, bright light or both
• finding objects
• avoiding obstacles
• recognizing food on the plate
• seeing well even with glasses on

In Alzheimer’s dementia, there are five main areas of visual deficit that can affect perception.

(See the last section, below, for some ways to help with these issues.)

• reduced ability to detect motion
• reduced peripheral vision
• loss of depth perception
• difficulty recognizing colors, especially in the blue-violet range
• reduced contrast sensitivity to gradients of color–trouble picking out objects that are surrounded by similar colors, i.e. finding the toilet in a bathroom where the floor, walls and toilet are all white

Alzheimer’s disease can be detected through an eye test

According to researchers, changes in your sight and smell may be the key to early detection of Alzheimer’s disease. A decreased sense of smell is an early clue. In the case of vision, people with Alzheimer’s have fewer blood vessels and less blood flow in the retina (back of the eye). The retinal nerve that comes out of the brain gets narrower and this can be detected by an eye test that uses a non-invasive scanning technique called OCTA (optical coherence tomography angiography).

Having a thinner retina can also cause blurry vision at first that may interfere with normal activity, making things to appear hazy or out of focus.

Results from two studies show that OCTA can see signs of Alzheimer’s disease in a matter of seconds. Researchers at Duke University in North Carolina compared the retinas of 39 people with Alzheimer’s, 37 people with Mild Cognitive Impairment (MCI), and 133 healthy people. The average age was 71.

The researchers excluded various people from the study, including people with non-Alzheimer’s dementia, diabetes, high blood pressure, neurological conditions like multiple sclerosis, glaucoma, age-related macular degeneration or poor vision.

They took scans looking at the tiny blood vessels in different parts of the retina, and then compared blood vessel density between the groups. They found that people with Alzheimer’s had fewer blood vessels and less blood flow in the retina than healthy controls and those with MCI, and that a specific layer of the retina was thinner. They also found that the small blood vessels in the retina are altered even in patients who have a family history of Alzheimer’s but have no symptoms.

Because the retina is connected to the brain by way of the optic nerve, researchers believe that the deterioration in the retina and its blood vessels may mirror the changes going on in the blood vessels and structures in the brain, thereby offering a window into the disease process.

Because genes play a significant role in how Alzheimer’s disease begins and progresses, another team of researchers from Sheba Medical Center in Israel examined 400 people who had a family history of the disease but showed no symptoms themselves. They compared their retina and brain scans with those who have no family history of Alzheimer’s.

They found that the inner layer of the retina is thinner in people with a family history. The brain scan showed that their hippocampus, an area of the brain that’s first affected by the disease, had already begun to shrink. Both factors, a thinner inner retina layer and smaller hippocampus, were associated with scoring worse on a cognitive function test.

The goal of this latest research is to find a quick, inexpensive way to detect Alzheimer’s at the earliest signs. Diagnosing Alzheimer’s is a currently a challenge. Some techniques can detect signs of the disease but are impractical for screening of millions people: Brain scans are expensive and spinal taps can be harmful. Instead, the disease is often diagnosed through memory tests or observing behavior changes. By the time these changes are noticed, the disease is advanced. Even though there is no cure, early diagnosis is critical as future treatments are likely to be most effective when given early. Early diagnosis would also give patients and their families time to plan for the future.

Regular eye exams are important

I wondered how the doctor could ascertain what Morris’s eye glass prescription was since Morris was unable to read the eye chart. The ophthalmologist assured me that they have their way of checking someone’s eyes without verbal feedback. The doctor adapts the test for the patient, and allows for more time. It is important, however, that someone who knows the patient well accompanies him/her.

People with dementia can have the typical causes of sight loss that many aging people have, including cataracts, macular degeneration, normal aging of the eye, and stroke.

Ways to help your patient with sight loss and dementia

• Make sure their eyeglass prescription is current.
• Clean the glasses often, and try to prevent loss or misplacement by attaching them to a strap, lanyard or chain.
• Improve the lighting where the patient lives, and install automatic lights that come on at dusk.
• Use contrasting colors to help the patient discern places and things, i.e. Serve colorful veggies (which are higher in antioxidants and vitamins) on a white plate. Put DO NOT ENTER signs on outside doors, if there is a risk your patient might wander, etc.
• Play books on tape, or read to your patient if he/she is unable to read.
• Focus on what your patient can do and is familiar with, and help him/her to have positive experiences.

Barbra Cohn cared for her husband Morris for 10 years. He passed away from younger-onset Alzheimer’s disease in 2010. Afterward, she was compelled to write “Calmer Waters: The Caregiver’s Journey Through Alzheimer’s & Dementia”—Winner of the 2018 Book Excellence Award in Self-Help—in order to help other caregivers feel healthier and happier, have more energy, sleep better, feel more confident, deal with feelings of guilt and grief, and to ultimately experience inner peace. “Calmer Waters” is available at Amazon, Barnes & Noble, Boulder Book Store, Tattered Cover Book Store,  Indie Bound.org, and many other fine independent bookstores, as well as public libraries.