So many of us take our vision for granted. We open our eyes and we are able to focus on images and see color, details and depth.
But it’s not that simple. There are a number of parts of the human eye that all work in tandem to process light so that the brain can ultimately interpret it into images you’ll recognize: a tree, a family member’s face, your couch, or the food on your plate.
Understanding how our eyes work by learning more about the various parts of our eye can help us take better care of our all-important vision.
The Cornea
What it does:
It all starts with our cornea, the transparent dome-shaped layer at the front of the eye that covers the iris, pupil, and anterior chamber.
The primary job of the cornea is to refract — or bend — light so that the eye can focus. Another role the cornea plays is that of protecting the eye by acting as a barrier against dirt, germs, and other foreign objects.
What can go wrong:
If your cornea is damaged in any way, whether by disease, injury or infection, it can become scarred and unable to focus the light, blocking or distorting your vision.
The Pupil
What it does:
The pupil is the black “dot” at the center of your eye. The pupil actually isn’t a structure, but an opening where light enters the eye, starting the sight process. It’s black because it absorbs the light that passes through and doesn’t reflect that light back.
What can go wrong:
Some conditions may cause pupils to not be reactive to light and to be smaller than normal. Trauma that penetrates the iris can also cause an abnormally shaped pupil.
The Iris
What it does:
The iris is the colored part of your eye. It is a ring-shaped membrane (made of connective tissue and muscle) surrounding the pupil. Its job is to regulate the amount of light that comes into the eye via the pupil by contracting to shrink the pupil or widen it.
What can go wrong:
Trauma, inflammation, or inherited conditions can impact the iris.
The Lens
What it does:
The lens is the small, clear disk at the inner part of the eye. It works in conjunction with the cornea to focus light directly on the retina. After the light passes through the pupil, it hits the lens.
What can go wrong:
Cataracts, a painless but cloudy lens, are one of the most common things that can go wrong. They can be caused by aging, diabetes, trauma, some medications and excessive UV light exposure.
The Vitreous Humor
What it does:
This colorless, gel-like substance fills the center of the eye and helps give your eye its round shape and provides visual clarity. Light passes through it on the way to the retina. It can also act as a shock absorber in case you get hit in the head.
What can go wrong:
As part of the normal aging process, the vitreous humor can degenerate significantly and even become detached, causing flashes of light, torn blood vessels, or a retinal tear. It also decreases in viscosity and can separate from the retina, causing floaters in your vision.
The Retina
What it does:
This thin, light-sensitive tissue in the back of the eye contains cells called photoreceptors (also known as rods and cones). These cells turn light into electrical impulses and send them along to the brain via the optic nerve.
What can go wrong:
There are a number of retinal diseases and conditions, including retinal tears, detachment, and diabetic retinopathy. All of these can cause disturbances in your vision and even blindness.
The Optic Nerve
What it does:
It’s the optic nerve that connects the eye to the brain, and it’s the brain that is responsible for interpreting the electric signals from the retina as images. Once the electrical signals leave the retina, they travel through the optic nerve via millions of tiny nerve fibers to the brain (specifically, the visual cortex).
What can go wrong:
Damage to the optic nerve can be the result of eye diseases (such as glaucoma), trauma to the eye, toxins (including tobacco and alcohol) and some genetic conditions.
Are you taking good care of all the parts of your eyes? With regular eye exams, good nutrition, exercise, and protective eyewear, you can help protect your vision and avoid vision problems. Contact us if you need an eye exam or if you’ve noticed any symptoms with your vision. We’re here to help you keep your eyes healthy.
