Vision changes with age: What are normal ageing changes in the eye?

Our eyes exhibit age-related changes in performance as we age — particularly as we reach our 60s and beyond.

Some of these changes, such as presbyopia, are perfectly normal and don't signify any sort of disease process. While cataracts can be considered an age-related disease, they are very common among seniors and can be readily corrected with cataract surgery.

Some of us, however, will experience more serious age-related eye diseases that have greater potential for affecting our quality of life as we grow older. These conditions include glaucoma, macular degeneration and diabetic retinopathy.

Common age-related vision changes

Presbyopia

After you pass the milestone age of 40, you'll notice it's more difficult to focus on objects up close. This is because the lens inside the eye begins to lose its ability to change shape — a process called presbyopia.

For a time, you can compensate for this gradual decline in focusing ability by holding reading material farther away from your eyes. But eventually you will need reading glasses, progressive lenses or multifocal contact lenses.

Some corrective surgery options for presbyopia also are available, such as corneal inlays, monovision LASIK, conductive keratoplasty and refractive lens exchange.

As you continue to age through your 50s and beyond, presbyopia becomes more advanced. You may notice the need to change your spectacle or contact lens prescriptions. You may also find that a single prescription or pair of glasses is no longer the best solution for all your visual needs.

As an example, you may need one pair of glasses for a normal range of tasks and another that emphasises intermediate ranges for working more comfortably at the computer and around your desk or workstation.

Cataracts

Even though cataracts are considered an age-related eye disease, they are so common among over 60's that they also may be classified as a normal ageing change.

It's estimated that more than 700,000 people in Australia and some 370,000 in New Zealand have some degree of visually impairing cataract formation in their eyes. As you enter your 70s, the percentage is even higher.

Thankfully, modern cataract surgery is extremely safe and so effective that 100 percent of vision lost to cataract formation usually is restored. In Australia bout 250,000 cataract surgeries are performed each year and about 30,000 in New Zealand making it the most common elective surgery.

If you are noticing vision changes due to cataracts, don't hesitate to discuss symptoms with your optometrist.

It's often better to have cataracts removed before they advance too far. Also, now have options for trying multifocal lens implants or accommodating intraocular lenses that potentially can restore all ranges of vision, thus reducing your need for glasses.

Major age-related eye diseases

Macular degeneration

Also called age-related macular degeneration or AMD, macular degeneration is a leading cause of blindness among the elderly. According to Good Vision for Life, in Australia more than 1.25 million people have some degree of age-related macular degeneration. Due to the ageing of the population, that number is expected to more than double to by 2050. In addition, there are more than 8 million at risk of developing the condition. While in New Zealand around 250,000 cases exist at present.

Glaucoma

Your risk of developing glaucoma increases with each decade after age 40, from around 1 percent in your 40s to up to 12 percent in your 80s.

Diabetic retinopathy

According to Diabetes Australia, more than 1.2 million Australian are known to have diabetes. Another 500,000 are silent or unknown Type 2 diabetics. In 2019 the New Zealand Ministry of Health put their number of diabetics at 250,000 most of them with Type 2. Among known diabetics who have had the disease for more than 20 years all of those with Type 1 diabetes and over two thirds of those with Type 2 will have some degree of diabetic retinopathy that could lead to permanent vision loss.

Other age-related eye changes

While we often think of ageing as it relates to conditions such as presbyopia and cataracts, more subtle changes in our vision and eye structures also take place as we grow older.

These changes include:

Reduced pupil size

As we age, muscles that control our pupil size and reaction to light lose some strength. This causes the pupil to become smaller and less responsive to changes in ambient lighting.

As a result of these changes, people in their 60s need three times more ambient light for comfortable reading than those in their 20s.

Also, the elderly are more likely to be dazzled by bright sunlight and glare when emerging from a dimly lit building such as a movie theatre. Spectacles with photochromic lenses and anti-reflection coating can help reduce this problem.

Dry eyes

As we age, our bodies produce fewer tears. This is particularly true for women after menopause. If you begin to experience a burning sensation, stinging, or other eye discomfort related to dry eyes, use artificial tears as needed throughout the day for comfort, or consult your optometrist or GP for other options such as prescription dry eye medications.

Loss of peripheral vision

Ageing also causes a normal loss of peripheral vision, with the size of our visual field decreasing by approximately one to three degrees per decade of life. By the time you reach your 70s and 80s, you may have a peripheral visual field loss of 20 to 30 degrees.

With the loss of visual field comes and increased risk of vehicle accidents, so make sure you are more cautious when driving. To increase your range of vision, turn your head and look both ways when approaching intersections.

Decreased colour vision

Cells in the retina that are responsible for normal colour vision decline in sensitivity as we age, causing colours to become less bright and the contrast between different colours to be less noticeable.

In particular, blue colours may appear faded or "washed out." While there often is no treatment for this normal, age-related loss of colour perception, you should be aware of this loss if your profession (e.g. artist, seamstress or electrician) requires fine colour discrimination. However, if your fading colour vision is also due to cataracts, much of the loss can be restored with cataract surgery.

Vitreous detachment

As we age, the gel-like vitreous inside the eye begins to liquefy and pull away from the retina, causing "spots and floaters" and (sometimes) flashes of light. This condition, called vitreous detachment, is usually harmless. An increase in floaters and flashes of light can also signal the beginning of a detached retina — a serious problem that can cause blindness if not treated immediately. If you experience flashes and floaters, see your optometrist immediately to determine the cause.

What you can do about age-related vision changes

A healthy diet and wise lifestyle choices, such as not smoking, are your best natural defences against vision loss as you age.

Also, you need to have regular eye examinations with a caring and knowledgeable optometrist.

Be sure to discuss with your optometrist and and all concerns you have about your eyes and vision. Discuss any history of eye problems in your family, as well as any other health problems you may have.

Your optometrist needs to know what medications you take (including non-prescription drugs, vitamins, herbs and supplements). This will help with appropriate recommendations to keep your eyes healthy and functioning at their optimum level throughout your lifetime.

Page published on Tuesday, 17 March 2020