Updated November 2019
It is an inevitable fact that as we get older, the body ages. And unfortunately, this ageing does not exclude the eye and the entire vision system. The eye is a complicated organ with many structures within it. And when one of these structures is threatened by age, our vision becomes compromised.
But is it inevitable that our vision will worsen with age? And what can we expect?
In order to break this all down, let’s start with some basic eye anatomy.
The Lens – The Eye’s Focus Mechanism
One of the eye’s most important parts is a structure called the lens. Much like an artificial lens in a pair of eyeglasses, the lens allows our eyes to focus and unfocus, enabling us to view objects at different distances quickly.
Viewing distance objects requires the eye to relax the lens, decreasing lens convexity, or outward curvature. Viewing near objects requires an increase in convexity of the lens, creating more focus power. This provides us with magnification for close object viewing.
In most cases, usually before the age of 10, the lens works as it should: the lens changes convexity quickly and our eyes can switch from near to far objects with no complications. However, around the time of middle school, the ability of the lens to change convexity when viewing distance objects to near objects slowly decreases. And as the lens ages, the ability of the lens to change convexity only gets worse.
Presbyopia: Aging of the Lens
When we reach the age of around 40, the lens has hardened due to age and can simply no longer focus on near objects as well. Until soon, most people who still can see clearly when viewing distant objects are not able to read print within arms reach. They must hold the newspaper or book further and further away to see clearly.
This phenomenon is known as presbyopia, a universal condition affecting every person cross-culturally who lives past the age of 45. While there is no surgical treatment for the condition, there are options to help with presbyopia, such as bifocal eyeglasses, contact lenses, or laser vision correction modified for monovision.
Cataracts: Clouding of the Lens
A normal part of eye ageing, cataracts form when the proteins contained in the lens start to break down and clump together, causing cloudy spots throughout the line of vision. Although the amount and pattern of cloudiness in the lens, as well as the rate at which it develops, can vary, the result is blurry vision that cannot be corrected with contact lenses or eyeglasses. Cataracts are not painful and can be treated with non-invasive surgery.
The Retina – The Light Communicator
The retina is made up of nerve cells that receive focused light from the lens, then signals the brain to create images.
With age, the retina wears down and degenerates, severely affecting vision. There are a number of serious eye diseases that are directly caused by the degeneration of the retina.
Age-Related Macular Degeneration
Age-related macular degeneration, or AMD, is a serious eye disease that occurs when the macula, the small central area of the retina, ages and breaks down. Responsible for fine vision and color detail, when the macula is compromised, the result is blind spots, distorted vision, and possible blindness.
Diabetic retinopathy is a retinal disease that affects aged people who suffer from diabetes. In this case, the tiny blood vessels in the back of your eye deteriorate and leak fluid into and under the retina. New, replacement blood vessels start to grow, but they are misshapen and distorted and can lead to scarring and swelling of the retina. The result is blurry, distorted vision that can lead to blindness in some cases.
The Optic Nerve – The Eye/Brain Connector
Located at the back of the eye, the optic nerve carries impulses formed by the retina directly to the brain. A part of the central nervous system, the optic nerve is a major component of the visual system and damage will result in vision loss and blindness.
Glaucoma is a serious, progressive disease that directly affects the optic nerve. The 3 most common types are open-angle glaucoma, angle-closure glaucoma, and normal-tension glaucoma.
In the case of open-angle glaucoma and angle-closure glaucoma, the fluid that normally drains from the eye through a series of eye canals is blocked, causing a build-up of pressure, called intraocular pressure, or IOP. This pressure is placed directly on the optic nerve, leading to damage which results in irreversible vision loss. In normal-tension glaucoma, the eye’s drainage system is functioning as it should and the IOP is within the normal range. Inexplicably, the optic nerve continues to sustain damage.
Optic neuritis is an inflammation of the optic nerve that causes damage and can result in vision loss, blurring, and pain. Usually manifesting in one eye, optic neuritis is often a precursor of multiple sclerosis, a disease that attacks the nerves of the body.
It is inevitable that like the body, the eyes will age. And with age, the structures within the eye change and break down. With this comes a range of conditions and diseases to be aware of. Some, like glaucoma, come on suddenly and can result in irreparable vision loss. Others, like cataracts, are completely curable with simple surgery.
Whatever the condition, it is of the utmost importance that you engage in annual eye exams. Our optometrists will carefully examine and track your eye health so these eye diseases do not sneak up and steal your sight.