A Simple Guide to How Our Eyes Work
The experts at Ocumetics explain how we see, common eye conditions and how to care for our eyes so we can enjoy years of good vision.
After the brain, the eyes are the second most complex organ in our bodies. Each eye contains over two million working parts that quickly adjust to different conditions and environments to identify colours, objects and more. It should come as no surprise that such a complex and essential organ requires proper care.
“I’d like to help dispel some uncertainty that people feel about their own eyes and their eye health,” says Dr. Garth Webb, a dedicated optometrist, and Founder, and Chief Scientific Officer of Ocumetics, a Canadian-based research and development company. Founded in 2012, Ocumetics is dedicated to vision enhancement with its unique, advanced accommodating lens technology.
“When a person loses the ability to see near objects clearly without glasses as they grow old, it simply means that the lens inside their eyes has lost the ability to change its shape, increasing its power to bend rays of light and see near objects clearly, ” says Dr. Webb.
How the eye works
The cornea (the clear front layer of the eye) bends rays of light from objects in our environment to form images of them on our retina — a thin layer of light-sensitive nerves in the back of our eyes.
The amount of light that enters the pupil (the black circle in the eye) is controlled by the iris (the coloured tissue behind the cornea), which expands or contracts to control the amount of light that enters the eye.
Light then passes through the lens, which also bends rays of light to focus them on the retina. Most of the eye’s focusing power comes from the cornea, but its shape and power are fixed. The lens does not bend rays of light as strongly as the cornea, but its curvature changes as we look from distant to near objects and back again to focus images of all images in our environment on the retina. The retina captures focused images of our surroundings and sends these to the brain, where we interpret these images. The brain is responsible for saying, “Oh, that’s Aunt Minnie,” or “I need to wait here until the light turns green.”
What causes eye degeneration
At birth, the lens is crystal clear and flexible. When we look at near objects, our brain sends signals to the eye, where muscles contract to increase the curvature and power of the lens, allowing us to see near objects clearly.
As we age, the proteins in the eye’s lens gradually stiffen, so the lens becomes less responsive to signals from the brain that try to make the eye’s optical system focus on objects up close. This process is called presbyopia. In addition to stiffening, the lens also becomes cloudy with age. A cloudy lens is called a cataract. When the lens becomes cloudy enough to interfere with normal activities of daily life, a surgical procedure is recommended to remove the cloudy lens and replace it with a clear, artificial lens .
Outside of the inevitable effects of aging, there are many other factors, such as genetics or overall health, that also affect eye health. Autoimmune disorders, diabetes, and high blood pressure can all lead to eye damage. Myopia (nearsightedness) is a common eye problem typically beginning in childhood that affects nearly 30 per cent of Canadians and almost 42% of American citizens. People with myopia can see up close clearly, but their distant vision is blurred.
Farsightedness (hyperopia) is a condition in which the cornea and lens do not have enough power to focus rays of light from distant objects on the retina. Farsighted individuals who develop presbyopia have even more difficulty seeing up close clearly than they do at a distance.
Another common condition is astigmatism, which may be present at birth or develop after an eye injury, disease or surgery. It is usually a result of an uneven curvature of the cornea so that rays of light passing through different locations on the cornea are bent differently. Astigmatism causes blurry vision when looking at images at a distance or up close, and it is often combined with myopia or hyperopia.
Eye health tips
“We can’t stop the aging process, but we can compensate somewhat for genetic shortfalls,” says Dr. Webb, expressing that it’s important to ask questions like, “What are the normal signs of aging eyes?”
Being aware of what is normal will help alert you to a potential problem. Protect your eyes by making healthier choices, such as exercising regularly, eating a balanced diet that includes proteins, fruits, grains, dairy and vegetables, and wearing sunglasses to protect against the sun. In addition to leading a healthy lifestyle, Dr. Webb stresses the importance of getting regular eye exams.
“The eye is actually able to compensate for significant visual loss, which is a blessing and a curse,” explains Dr. Webb. “The blessing is you can have a disease and still not suffer. The curse is you can have a disease and may not realize that you have it.”
That’s where routine eye exams come into play. Eye care professionals can diagnose diseases before they cause lasting damage, including cataracts, macular degeneration (damage to the central part of the retina called the macula that causes blurry vision), and glaucoma (damage to the optic nerve caused by increased pressure in the eye).
Eye exams can also detect diabetes, the accumulation of cholesterol, inflammatory diseases, high blood pressure, and even heart disease.
“Technologies are becoming sophisticated, and they are guiding people to make good health choices that serve their lives,” says Dr. Webb.
Ocumetics is developing an accommodating intraocular lens and believes this cutting-edge lens technology could end the need for corrective eyewear by helping people achieve clear distance and near vision. The Ocumetics team says the accommodating replacement lens will respond to the same biokinetics of the human eye, work with each person’s unique anatomy, and has the potential to provide clear vision at all distances.