24 October 2021

Why we lose our vision as we age

Written by Claire Bonneau

Sight is one of our primary senses that many of us use to interact with the world around us. From alerting us about the dangers of oncoming traffic to soaking in the beauty of an evening sunrise, our vision helps us process millions of data points every single day.

For older generations such as the baby boomers (those born between 1946-1964 at the turn of World War II), age is beginning to play a significant role in their visual health. This year, people born during the baby boomer generation will be turning 57-75, putting them at an elevated risk of developing new-onset visual impairment. With an estimated 70 million baby boomers currently living around the world, the global healthcare system needs to prepare for the impending need for visual health services

Around the world, serious ramifications of limited access to vision care have already become incredibly apparent. With 82% of people who are diagnosed with complete blindness aged 50 or older, it appears that there is a strong connection between decreased visual health and increased age — and yet, there is very little education being provided to our ageing population about this serious condition.² These numbers become more staggering, as the World Health Organization (WHO) estimates that over 2 billion people around the world are currently living with visual impairment — 65% of whom are also over the age of 50.²

So, despite the importance of vision in our day-to-day lives, it seems that it is incredibly common to lose our visual acuity as we age. So why, and how, do these visual disturbances occur, and how is our global community preparing to help our ageing population as they begin to experience vision loss?

How the eye works

To better understand visual loss, we first need to understand the anatomy and function of our visual system. Comprised of our eyes, multiple nerves and visual centres in our brain, the visual system is responsible for processing every single thing that we see — and as it turns out, that is actually quite complicated!

Starting as a beam of light bouncing off an object and being directed towards our eyes, it first passes through our cornea and lens. The light is bent and focused through the thin cornea and lens to enable it to be sent to our light receptors at the back of our eyes.³

Once the light has passed through the lens, it is then received by the retina at the back of our eyes. Covered in very sensitive light and colour receptors called rods and cones, the retina transmits the energy of the light into an electrical impulse that is transported to the brain via the optic nerve.³ This information is sent rapidly to your brain, which interprets it, and allows us to see what is right in front of us.

When this system is working perfectly, a person is said to have 20/20 vision (meaning you are able to see clear and accurate information from standing twenty feet away). The clarity of your vision can be dramatically impacted by a variety of factors, leading to a diagnosis of visual impairment.

What happens to our eyes as we age?

Just like every other part of our body, our eyes undergo changes as we age. With decreased muscle tone of our eyelids and increased difficulty bending and focusing light onto our retinas, it is very common for visual impairment to occur with age. In fact, while 4.4% of American adults aged 45-65 experience visual impairment, the number jumps to 7.2% by the time they reach age 75.

Chronic exposure to irritants, medical comorbidities, changes caused by our sun’s ultraviolet rays, and general wear and tear over time all can result in a loss of vision as we get older. From clouded corneas to the buildup of cholesterol as a yellowish-brown plaque throughout the eye, there are a variety of physical and physiological changes that lead to visual impairment as we age.

The most common age-related eye disorders

Visual impairment can be the result of a variety of different factors and medical conditions. Some of the most common causes of visual impairment (including blindness) around the world include:

  • Age-related macular degeneration — Caused by damage to the photoreceptors on our retina, macular degeneration is a very common age-related eye condition. With 196 million adults living with macular degeneration around the world, this condition is only going to become more prevalent as our population ages.²

  • Cataracts — Over time, the lens of our eye can begin to cloud. Caused by chronic high blood pressure, exposure to ultraviolet rays, other medical comorbidities and age, cataracts can lead to blurry and unfocused vision.

  • Corneal clouding — Also causing cloudy or blurry vision, increased opacity of the cornea can cause significant visual impairment. Corneal opacity is commonly caused by injuries to the eye, bacterial or viral infections, and vitamin deficiencies.

  • Diabetic retinopathy — Affecting many of the blood vessels throughout the body, uncontrolled diabetes has a profound impact on the health of the eyes. Damaged blood vessels can become leaky or blocked, causing retinal swelling and visual impairment. Chronically poorly controlled diabetes can cause additional injuries and scarring on the retina, causing permanent impairment or blindness.

  • Glaucoma — Caused by damage of the optic nerve, glaucoma is a serious progressive disease that worsens over time. People with glaucoma commonly report peripheral visual changes early into the disease, but if left untreated that can experience a complete loss of their vision.

  • Refractive errors — Do you or someone you know wear glasses or contact lenses? Caused by an abnormal shape or length of the eye, many people cannot properly focus light onto their retina. There are two common types of refractive errors:⁶

    • Myopia: Difficulty seeing objects that are far away (caused by light being focused ahead of the retina).

    • Presbyopia: Difficulty seeing objects that are close (commonly associated with being over the age of 40).

  • Trachoma — This common bacterial infection can cause substantial damage to the eyes if left untreated. Chronic infections of trachoma cause the eyelashes to bend inwards towards the eyes, resulting in permanent scarring and visual disturbances.

Increased life expectancy and continual population growth compound the problem

As visual impairments continue to impact millions around the world, it has become incredibly clear that we are not prepared to handle the upcoming increase in demand for high-quality visual healthcare services.

Despite being treatable, many people around the world are living with untreated refractive errors and cataracts. As our global community pushes towards improved public health for everyone, these issues remain unsolved problems that need to be addressed sooner, rather than later.

According to the United Nations World Population Ageing Highlights, in 2030 the number of people over the age of 60 is expected to increase by 46% (from 926 million in 2017 to 1.4 billion).⁷ So while our population continues to age, it is important now more than ever that we begin to organize our efforts for tackling the inevitable increase in age-related visual impairments diagnoses that are soon to come.

Using predictive science based on our current ageing population projections, scientists have been able to estimate the expected increases in common visual conditions like macular degeneration and glaucoma. If things continue on their current path, it was predicted that by the year 2030:⁶

  • Age-related macular degeneration cases will skyrocket to over 243 million cases (from 195 million in 2020).

  • Glaucoma cases will increase to 95 million cases worldwide (compared to 76 million cases in 2020).

Other age-related eye conditions such as presbyopia, cataracts, and general eye dryness are also projected to increase substantially over the next decade and a half. In order to meet the growing demand, we are going to need to expand access to affordable vision care.

The cost of vision loss

Because of the already existing high number of people living with visual impairment around the world, unfortunately, building the infrastructure to accommodate for the future of our ageing population will not come without a big price tag.

Currently, without accounting for future cases of visual impairment, it is estimated that it would cost the global community roughly 24.8 billion USD to catch up on essential vision care services like refractory error corrections and cataract surgeries.

And while this number is very large, it is not the most important cost associated with vision care that we should be addressing.

More important than the financial cost is the personal cost of living with untreated vision conditions. Leading to increased social isolation, loss of work, decreased independence, and increased disability, people diagnosed with visual impairments are significantly more likely to experience mental health conditions like anxiety and depression.

Additionally, a large number of people around the world are living with visual impairment conditions that are completely preventable and treatable. Of the total number of people experiencing visual impairment, the WHO estimates that at least one billion of these cases are preventable or have not been properly addressed due to a lack of resources.

The increased need for healthcare from causative conditions associated with visual changes adds additional healthcare costs — creating a vicious cycle of increased need for medical care. Correcting the care gap for people living with untreated visual impairment disorders around the world by integrating improved vision care practices into our societal structure is a lot of hard work — but the results are going to have a massively positive impact on every future generation.

A vision for a clearer future

So, with a lot of work ahead of us, it is important to note that there are ways for us to improve the way we address visual care for future generations. In a strategy suggested by the World Health Organization, approaching visual care at all levels of healthcare is one of the best ways to promote increased access to care. Some of their suggestions include:⁶

Increased access to eye care in community settings like schools and homes

Starting at the source, improving education about eye care to the general public is a great way to prevent unnecessary damage and injury to the eyes. Additionally, accessible care that meets people where they are is one of the best ways to help people stay on top of their health screening appointments.

Integrating eye care into primary care facilities

While there is definitely a time and place for seeing a specialist, oftentimes many people could benefit from routine check-ups from their general practitioners. Capable of diagnosing common eye conditions and providing guidance for the best possible treatment options, integrating an increased focus on vision care at a primary care level is necessary to reduce the number of preventable cases of visual impairment.

Incorporating eye care into acute medical settings

When in-patient and out-patient care is required for any medical condition, it is advised that eye care be integrated and considered in every patient's care plan. Reinforcing education about eye care is a helpful way to encourage people to take better care of their sight while also reducing their risk for negative long-term health concerns. Additionally, if a patient does require support or resources for their vision health, they can be easily connected to a specialist for additional education and follow-up.

Improving access to specialized eye care procedures

If a person has already sustained some extent of visual impairment, getting them access to the care and procedures they need to prevent the continued progression of the disease is essential. Improving the number of eye care specialists and the capacity for more procedures to be done each day is essential for preventing long-term disability and future health problems.

So, as we can see, there is a clear path ahead for us, should we choose to take it. With increased access to ever-changing modern medical technology and improved diagnostic tools, we have every possible opportunity to address the soon-to-be endemic levels of age-related visual impairment coming our way. As our leading global health ambassadors continue to raise awareness and propose solutions for this problem, it is also our responsibility to treat our eyes with additional care.

Sources:
  1. 2020 Census Will Help Policymakers Prepare for the Incoming Wave of Aging Boomers | United States Census Bureau

  2. WHO releases new global estimates on visual impairment | World Health Organization

  3. How the Eye Works | NIH: National Eye Institute

  4. Percentage of adults aged 45 years and older with vision impairment in the U.S. from 2015 to 2017, by age | Statista

  5. Cataracts | The Mayo Clinic

  6. Eye care, vision care, vision impairment and blindness | World Health Organization

  7. World Population Ageing Highlights | United Nations

  8. Visual impairment and risk of depression: A longitudinal follow-up study using a national sample cohort (2018)

The author, Claire Bonneau, is a medical writer and certified trauma operating room nurse.

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