Your Eye and Your Vision
Eyes are amazing. For the sighted, vision is the sense that is used the most and how we gather the majority of the information we rely on every day. To understand vision problems, including refractive errors, and the surgeries used to correct them, it helps to first have a basic understanding of the anatomy of the eye.
The cornea is the clear outer shell of the eye. The cornea is responsible for about 65% to 75% of the eye’s focusing power. The cornea bends light to help focus it on the retina. This is called refraction.
Iris and Pupil
The iris and pupil control the amount of light that passes to the lens and retina. The iris is the colored part of the eye, and the pupil is the black part in the center. The pupil is the opening that light passes through to reach the back of the eye. Muscles in the iris control pupil size, dilating the pupil when light is dim and making the pupil small when light is bright.
The lens sits right behind the pupil. It refines the focus of the light. Muscles inside the eye move the lens to focus on fine details up close. This is called accommodation. Loss of accommodation is what creates the need for reading glasses age people age.
The retina covers the inside of the back of the eyeball. Light that passes through the cornea and lens is focused on the retina. The retina receives the images and converts them into electrical signals, so they can be picked up by the optic nerve and transmitted to the brain.
The optic nerve connects the eye to the brain. It is made up of more than a million nerve cells. This nerve carries the electrical signals from the retina to the brain where they are processed.
Aqueous and Vitreous Humor
The front section of the inside of the eye, between the cornea and lens, is call the anterior chamber. It is filled with liquid, called aqueous humor, that bathes the lens and provides nutrients to the cornea and lens. The rear chamber of the eye is called the posterior chamber, and is filled with a gel-like fluid called vitreous humor.
The sclera is the white of the eye. It also extends all the way around the back of the eye forming the outside of the eye where the muscles that turn the eye are attached.
To learn more about your eyes, eye health and your vision, please search this directory for a list of ophthalmologists in your area and schedule your initial consultation.