Declining Vision and Memory
Being an owner of a Home Care Company for Older Adults I have been faced with many questions from families and client’s themselves. Even before, working as an RN on a Skilled Nursing Floor, many of these questions were fairly consistent. One of the main questions I was asked on a daily basis always involved the client's visual or memory impairment: Why has my dad’s vision declined so fast? Why is he forgetting more? Why is he/she not eating? I have the food in the refrigerator, but it is never touched. Why won’t my parents go out anymore and socialize?
Even though all of these questions don’t specifically discuss visual or memory impairment, usually my answer did: As your dad is not able to register his peripheral field, it is difficult for him to navigate the refrigerator; As memory and recall has declined as well as vision, they might be embarrassed to go in public and show this “deficit.”
Being a friend or a child of someone who is aging can bring about much confusion. There are so many interrelated factors and it is hard to pinpoint just one: Isolation, vision, stress, mobility, etc. One of the most consistent relationships I have noticed was visual decline and memory impairment going hand and hand. This led to much research as I, and families, were curious why this was occurring.
One of the first studies I read was a Meta-Analysis. A meta-analysis investigates two or more similar studies. This specific analysis included 14 other studies which had a total of over 6 million participants. The conclusion was simple: Visual impairment is associated with the increased risk of dementia and memory impairment (Shang, 2023).
Visual Deficits and their Relation to Memory Impairment
Macular Degeneration has a higher risk of developing Dementia or Alzhiemers.
Cataracts may be a risk factor, but further investigation is needed.
Another study showed Cataract has no connection with Alzehimers.
Glaucoma and Vascular Dementia can develop together.
Let's dive into specific types of visual impairments and their risks. Macular Degeneration is a visual deficit that primarily affects the central vision. In a study conducted by Dr. Hou Ren Tsai, he found that individuals with Macular degeneration have higher risks of developing dementia or alzhiemers. Cataracts, which can lead to cloudy and blurry vision, have had conflicting results. Some research has found a possible correlation. In Zhernrong Xiong’s study, they concluded that cataract may be a risk factor, but it requires further investigation as it is not clear. A different study by Shulei Man showed that there was no connection between cataracts and Alzheimers. Again, I must remind you that Alzheimers is just one form of dementia.
Glaucoma is a different case. Glaucoma is an eye condition that affects the optic nerve. This is usually caused by increased pressure in the eye. Studies show that Open Angle Glaucoma has been connected with Dementia. One of the biggest relationships is between Glaucoma and Vascular Dementia. Vascular Dementia, as the name denounces, is caused by insufficient blood flow to the brain. This can be caused by a stroke, diabetes, or another vascular affecting disease. Glaucoma can also be caused by vascular insufficiency. Due to these similarities, Glaucoma and Vascular Dementia seem to develop together.
Even though this study solved the basis of the question, I still had many more: Does visual impairment lead to memory impairment? Or is it the other way around? Are we mis-labeling behaviors as being caused by dementia while they were actually caused by visual impairment? Can addressing one slow down the progress of the other? What interventions can we put in place?
Does Visual Impairment Lead to Memory Impairment?
There is an increased risk that memory impairment can develop, but it is not definite.
“Risk” does not mean the older adult will get dementia. It means that there is a higher chance of them forming a memory impairment compared to an older adult without any visual deficits. I have cared for so many adults with macular degeneration, cataracts, and other age related eye disorders who are sharper than me! Also, not all memory impairment is Dementia. Dementia is a broad term. There are over 150 different types of dementia affecting different aspects of our brain, caused by different factors, and have different processes. Alzhiemers is just one form of dementia.
Are the Behaviors you see caused by Vision or Memory Impairment?
Behaviors can be influenced by both vision and memory impairment.
Focus on stimulation to maintain those pathways.
With these studies showing that visual decline is in some way associated with memory impairment, we can dive into the big questions. The first being: Are these behaviors caused by vision impairment or memory impairment? The answer: both! Both impairments go hand and hand. They feed off each other. For example, Bob is a 83 year old man with Macular Degeneration and Mild-Moderate Dementia. His daughter says that he has a hard time recalling her face, and the rest of the family. This is a visual issue as Bob may not be able to see her face well enough for his brain to draw that connection, but also recalling information diminishes with dementia. It could be caused more by vision or by dementia. It is hard to know specifically, but it is important to treat both.
Some behaviors could be “misdiagnosed” if you solely label it as one or the other. “Bob has forgotten his doctor appointment, it has to be the dementia.” Not necessarily, it could also be influenced from not being able to read the calendar well, or mislabeling days.
I tell all of our Caregivers to focus on stimulation to maintain those pathways in the brain, if they are not being”stimulated” they are more prone to lose that ability. This is the same for Vision. With that aspect of the brain not being used, corresponding functions are lost as well. Now, you might say how does this loss in vision lead to other loss of function? Vision is interconnected with so many aspects of our life. Ability to recall our friends and family based on facial recognition, going into the refrigerator and picking out what food we want to eat, looking at our calendar and seeing what appointments we have.
What interventions can we put in place?
Focus on treating both Vision and Memory impairment.
It is important to treat and care for both impairments. Treating one and neglecting the other is not optimal! For the eyes, make sure to schedule regular eye exams, take prescribed eye drops at the prescribed time, and protect eyes from UV rays or sunlight. For memory, like said above, stimulation, stimulation, stimulation! Keeping the brain working is key. That can be playing solitaire or reminiscing about the past. Ask questions to encourage memory recall. Other ways to help memory can include medication, supplements, and exercise.
Conclusion
To all the families asking, we can now say that vision and memory impairment do have a relationship. Bob might not be able to recognize his daughter, but the family knows that there are many factors affecting that. Making sure to focus on both is the key to minimizing behaviors and even slowing the process. Even with all the information and studies discussed in this article, there are so many other questions that can be asked. We only scratched the surface. It is important to always discuss everything with a doctor. Dementia is so broad and has so many inter-relatted factors, and vision is only one. Luckily we live in a modern world of research, and more results are found each day!
References
“Cataract Removal Linked to a Reduction in Dementia Risk.” National Institute on Aging, www.nia.nih.gov/news/cataract-removal-linked-reduction-dementia-risk. Accessed 7 Aug. 2023.
Hou-Ren Tsai a, et al. “Risk of Subsequent Dementia or Alzheimer Disease among Patients with Age-Related Macular Degeneration: A Systematic Review and Meta-Analysis.” American Journal of Ophthalmology, 12 Nov. 2022, www.sciencedirect.com/science/article/abs/pii/S0002939422004263.
Person, et al. “Study Finds Association between Preventable Vision Impairment and Risk for Dementia.” Healio, 17 July 2023, www.healio.com/news/ophthalmology/20230717/study-finds-association-between-preventable-vision-impairment-and-risk-for-dementia#:~:text=A%20study%20on%20a%20large,a%20high%20number%20of%20people.
Su, Cheng-Wen, et al. “Association between Glaucoma and the Risk of Dementia.” Medicine, Feb. 2016, www.ncbi.nlm.nih.gov/pmc/articles/PMC4998642/.
Xianwen Shang MPH, et al. “The Association between Vision Impairment and Incidence of Dementia and Cognitive Impairment: A Systematic Review and Meta-Analysis.” Ophthalmology, 8 Jan. 2021, www.sciencedirect.com/science/article/abs/pii/S0161642020312069.
