Learning about your eye health can seem overwhelming. At Eden Prairie Eye Care, we believe that our patients should understand:
How your vision works
Common eye conditions
Common tests performed during an eye exam
The human eye is a small, complex structure that contains an immense network of blood vessels, cells, nerves, and specialized tissues. In order to understand how your vision works, it’s important to understand its main parts. These include:
Cornea: The clear, transparent tissue covering the front of the eye.This is the part of your eye that light travels through.
Iris: This circular ring of muscles is the colored part of your eye. It is located immediately in front of the lens and controls the size of the pupil.
Pupil: The opening in the center of the iris that regulates the amount of light entering the eye.
Lens: Located behind the pupil, the lens bends light rays and focuses them on the retina.
Retina: The retina is a light-sensitive tissue at the back of the eye that changes the light from the lens into nerve signals.
Macula: Sensitive, central area of the retina that is devoid of blood vessels. It allows individuals to clearly and sharply see colors, shapes, and details.
Rods and Cones: Cells used by the retina to process light.
Optic Nerve: The bundle of nerve fibers at the back of the eye. The optic nerve carries visual impulses from the retina to the brain.
The eye is a delicate system. A slight alteration to any of these components can cause vision issues or impact your eye health.
Common Eye Conditions
During your comprehensive eye exam, your optometrist may use terms you are not familiar with to explain your vision issues. Below is a list of common eye conditions to help you better understand your diagnosis.
Astigmatism: When your cornea or lens is shaped irregularly, light cannot focus on the retina properly. This condition is known as astigmatism and results in blurry or distorted vision.
Hyperopia: Commonly known as “farsightedness,” hyperopia occurs when incoming light from far away doesn't properly focus through the lens onto the retina. A person with hyperopia can see distant objects better, but has a hard time focusing on nearby objects.
Myopia: Myopia is the opposite of hyperopia. Known as “nearsightedness,” myopia prevents people from focusing on distant objects clearly. This condition is caused when the cornea and/or lens is too curved for the length of the eyeball.
Presbyopia: Presbyopia is the decreased ability of the eyes to focus on near objects that commonly occurs with age. This usually occurs around the age of 40 but can vary from person to person. This causes the individual to have a hard time seeing small print and in dim lighting.
Glaucoma: During your comprehensive eye exam, your optometrist will measure the internal pressure of your eye and scan your retina. This is a test for signs of glaucoma. Glaucoma occurs when fluid builds up your eye, increasing pressure and damaging the optic nerve. When left untreated, glaucoma can lead to blindness.
Cataract: A cataract is the clouding of your eye’s lens. They can occur in one or both eyes, and are the most common cause of vision loss in people over age 40.
During a comprehensive eye exam, your optometrist will perform tests to determine your visual accuracy and eye health. Although these tests are tailored to your age and symptoms, here are some of the common tests you can expect during your eye exam:
Eye Dilation: An optometrist will use special drops to widen your pupils. This test is vital towards early detection of diabetes, glaucoma, and cataracts as well as other health and vision issues.
“Air Puff” Test: During an “air puff” test, a diagnostic machine called a non contact tonometer will puff air across the surface of your eye. This measures your internal eye pressure and determines whether you are at risk of or currently developing glaucoma or other eye conditions.
Phoropter: If your optometrist has discovered a vision problem, they will use a phoropter to quickly determine the corrective lenses needed for each eye.
Snellen Chart: You’ve hopefully seen this a few times in your life. The Snellen chart is either mounted or projected onto your optometrist’s wall and is usually topped with a giant E. This common test is used to measure your vision at several distances.