Visual Acuity and Longevity
- William Brandenburg, MD
- Oct 28
- 6 min read
Happy Halloween everybody! Hope everybody is dressing up, My kids are being Spiderman, Boba Fett, and a black cat. I am going out as Darth Vader. If you are new to parenting, you are probably also realizing that candy is an alcohol equivalent for children and they literally become “drunk” after several pieces of concentrated sugar. Sorry Mormon church…..concentrated sugar is a drug.
But enough about candy!
Today on Full Scope, we are going to talk about a very important Longevity Metric – Visual Accuity, or how clearly a person can see things.
For longevity metrics, we are going to look through 3 lenses
1. Common-Sense: Does it make sense that a given metric would impact longevity
2. Clinical: Do I see evidence that a given metric impacts longevity in my clinical practice
3. Research: Do research studies demonstrate that a metric impacts longevity.
So HERE WE GO
Common – Sense Approach
Sensing our environment accurately is extremely important for survival in both the pre-modern and modern world. Image trying to avoid a sabertooth tiger or since its Halloween, an axe murderer without vision…….
For most people, vision is primary human sensory organ. In fact 30-50% of the brain is dedicated to processing visual information. So vision must be very important!
Visual acuity is a measure of the sharpness and clarity of vision. Essentially it is a measurement of how clearly we can see things in our environment.
From a longevity standpoint, this passes the sniff test. Vision is obviously very important for finding food, avoiding predators, surviving attacks, building shelter, crafting tools, and more.
In the modern environment visual acuity is important for making social connections, building things, for many types of work, and even for activities of daily living (cooking, cleaning, getting dressed, etc.).
From this perspective, visual acuity seems tied to work, wealth generation, and independence, three variables with strongly correlated with longevity. The social connection peace is huge as well. Similar to hearing loss, vision loss also increases the risk of dementia. Anything that prevents us from fully engaging with the world and other people, likely increases dementia risk. Think everything from sedative medications/drug, to sensory loss, to isolation.
When vision is absent at birth or from an early age, people’s brains and other sensory organs can compensate considerably. For instance, some humans can even use echo-location and have developed an almost spidy-sense for understanding the world around them, in the absence of vision. But, when vision is gradually or suddenly lost, later in life, compensation is much more challenging. Honestly, these two groups should probably be looked at separately, with regard to how longevity is affected. But, due to limited data, we are going to batch these groups.
So, from a firs-principles, common-sense, logic standpoint, visual acuity seems very important for longevity
Clinical Approach
What about my clinical experience treating older sicker people in the hospital. Here are some thoughts.
- I see a tremendous amount of falls in the elderly due to poor vision. Often times these falls happen at night, in low light situations. Injuries from these falls are often devastating and sometimes even fatal. Some studies even quote a 30-50% mortality at 6 months for hip fractures from ground level falls in the elderly.
- Vision loss causes many people to lose their independence as they can no longer perform ADLs (getting dressed, doing laundry, cooking, cleaning, etc)
- As people lose the ability to see, reading, crafting, building, and socializing gets much more difficult. Without these things, cognitive (brain function) decline accelerates. Dementia follows.
So, from a clinical standpoint, loss of visual acuity negatively effects the longevity of patients in my clinical practice regularly.
Research Approach
What about in research studies? How does loss of visual acuity impact lifespan and mortality in clinical research studies.
Well, the findings are consistent across multiple populations on multiple continents. Loss of visual acuity is significantly correlated with an increased risk of dying. The greater the vision loss, the greater the risk. Below are 5 recent studies and their findings.
Ehrlich et al. 2021 Lancet. Meta-Analysis of 28 studies. 446,088 total participants from 12 different countries. The study looked at how vision impairment affects all-cause mortality for people 40 years of age and older with a minimum 1-year follow -up (sometimes > 10 years though). Hazard ratios were calculated for all-cause mortality at different levels of vision impairment per the below table.
20/20 vision is normal. As visual acuity gets worse, the bottom number gets larger (e.g. 20/40)
20/200 vision or worse is defined as “legally blind”.
All-cause mortality: the overall rate of death from all causes
Hazard ratio: a measure of how often a particular event (in this case death) happens in one group compared to another overtime.
Confidence interval: a statistical estimate of the potential probabilities for a given hazard ratio.
What this study demonstrates:
As vision impairment gets worse, all cause mortality (the chances of dying) increases. For vision equal to or worse than 20/40, all cause mortality increase by 29% (1.29). For those meeting criteria for legal blindness, all cause mortality increases by 89%.
Other recent studies confirm this result.
Han et al. 2022 showed that visual impairment increases death from injuries as well as cardiovascular disease. This study links visual impairment with heart disease, the biggest killer on the block. Those with moderate to severe visual impairment had a hazard ratio of 2.41 for cardiovascular mortality! Wow. So visual impairment can also be a sign of badness in other important organ systems, such as the heart, blood vessels, and brain.
Verbeek et al. 2022 showed that individuals with vision impairment scored lower on physical, cognitive, psychological, and social functioning. These vision impaired individuals had accelerated deterioration of activities of daily living (this is exactly what I have seen in the hospital!) Mortality risk for severe visual impairment in this study was 1.89 (89% increased risk of death)
Christ et al 2014 and Siantar et al 2015 showed similar mortality (death) risk for visual impairment as the above studies.
So multiple studies with diverse participants from different countries all show the same thing.
VISION IMPAIRMENT INCREASES THE RISK OF DEATH. As vision gets worse, risk increases.
How is visual acuity measured?
- Paper based charts for far and near vision (Logmar, Snellen, Tumbling E, etc)
- Longetrics uses the LogMar vision charts because it is considered the gold standard for visual acuity research.
- Virtual reality platforms for testing vision
- Vision screeners (like the device you look into at the DMV)
- Visual acuity is easy to measure; it is something a person can even monitor on their own if desired.
Ok, but why does this matter?
Because vision can be improved.
- Glasses and contacts can improve visual acuity immediately
- Procedures like LASIK, PRK (photorefrativekeratectomy), artificial lenses, and etc can cure visual impairment
- Just using your eyes and spending time outside can improve vision. Just putting up Snellen charts in classrooms has been shown to improve visual acuity in children.
- Spend at least 1 hour outside everyday, ideally more though. Natural light is very good for the eyes. Ever notice how bad your vision becomes when you stare at a screen for a few hours, then how it resolves after just 15 minutes outside, amazing! Consider a walk outside every 1-2 hours if you work at a computer.
- There are also eye training protocols, most of which are digital, that have been shown to improve visual acuity. Many people have had amazing results from consistent eye training.
- Like most things in the body, eyes must be used and challenged in order to maintain peak performance.
So the common sense, clinical, and research lenses are all in alignment. Vision impairment increases a person’s risk of dying. Therefore visual acuity is an important metric to measure for longevity!
So, don’t except vision loss. Measure your visual acuity regularly. If there is a deficit, Fix it! Additionally, consider checking for other health issues like heart disease and dementia, as visual impairment may be a sign of other underlying health issues.
Want to see how we measure visual acuity at Longetrics? Check out our youtube channel: Longevity Metrics @BillBrandenburgMD
References
- Ehrlich JR, Ramke J, Macleod D, Burn H, Lee CN, Zhang JH, Waldock W, Swenor BK, Gordon I, Congdon N, Burton M, Evans JR. Association between vision impairment and mortality: a systematic review and meta-analysis. Lancet Glob Health. 2021 Apr;9(4):e418-e430. doi: 10.1016/S2214-109X(20)30549-0. Epub 2021 Feb 16. PMID: 33607015; PMCID: PMC7966688.
- Han SY, Chang Y, Shin H, Choi CY, Ryu S. Visual acuity and risk of overall, injury-related, and cardiovascular mortality: the Kangbuk Samsung Health Study. Eur J Prev Cardiol. 2022 May 6;29(6):904-912. doi: 10.1093/eurjpc/zwab025. PMID: 33615358.
- Verbeek E, Drewes YM, Gussekloo J. Visual impairment as a predictor for deterioration in functioning: the Leiden 85-plus Study. BMC Geriatr. 2022 May 6;22(1):397. doi: 10.1186/s12877-022-03071-x. PMID: 35524168; PMCID: PMC9074345.
- Christ SL, Zheng DD, Swenor BK, Lam BL, West SK, Tannenbaum SL, Muñoz BE, Lee DJ. Longitudinal relationships among visual acuity, daily functional status, and mortality: the Salisbury Eye Evaluation Study. JAMA Ophthalmol. 2014 Dec;132(12):1400-6. doi: 10.1001/jamaophthalmol.2014.2847. PMID: 25144579; PMCID: PMC7894742.
- Siantar RG, Cheng CY, Gemmy Cheung CM, Lamoureux EL, Ong PG, Chow KY, Mitchell P, Aung T, Wong TY, Cheung CY. Impact of Visual Impairment and Eye diseases on Mortality: the Singapore Malay Eye Study (SiMES). Sci Rep. 2015 Nov 9;5:16304. doi: 10.1038/srep16304. PMID: 26549406; PMCID: PMC4637872.
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