Eye Illustration

Visual Axis of Right Eye

Close up of an eye

About the Eye

The human eye is a remarkable organ that allows us to see and experience the world around us through the sense of sight. Of all the five senses (sight, hearing, smell, touch, and taste), sight is considered to be the most important. We use our eyes in some way for virtually everything we do.

The eye is a small but very complex organ with many parts that all must work together properly in order for you to see well. The eye takes in light waves and converts them into electrical signals that the brain then uses to interpret a three-dimensional visual image. There are several steps that occur when light waves reflect off an object and enter your eyes. First, the light passes through the clear, protective surface of the eye called the cornea, which starts to bend the light waves. Then the light wave enters the dark center of your eye, which is called the pupil. The pupil regulates the amount of light that enters the eye by becoming very small in bright light or opening very wide in low light.

Once the adjusted amount of light passes through the pupil, it goes through another transparent lens (called the crystalline lens) that focuses the light further until it comes to a single point within the eye. The light then passes through a clear gel that fills the inside of the eye and makes up 80% of its volume. This is called the vitreous humor. Finally, the light reaches the back of the eye and the retina, which is covered by light-sensitive cells that transmit the photonic signals to the brain via the optic nerve.

Cataract is the term used to describe a natural clouding of the crystalline lens, which then causes the passage of light to the retina to be reduced and therefore vision to become blurry or dim. The formation of a cataract is unfortunately a normal part of aging for many people. It’s estimated that there are more than 90 million people around the world with cataracts.

Beyond aging, cataracts may also be the result of eye infections, some medications, injuries, or exposure to intense heat or radiation. Too much exposure to UV rays and various diseases, such as diabetes or metabolic disorders, can also cause cataracts. However, it’s estimated that 95% of cataracts are age-related, with the initial onset typically after the age of 40 and the incidence increasing with age.

The exact cause of cataracts is unknown, and there’s no way to prevent them from forming. Our bodies normally replace old cells with new ones. It’s believed that as our eyes get older, the old cells in the eye may build up. Some things you can do to slow down cataract formation are to limit exposure to UV rays, avoid smoking, check for high blood pressure and work toward bringing it into normal range, eat right and exercise to prevent obesity, and avoid excessive alcohol consumption.