An eye test helps determine how well a patient sees objects that are at least 20 feet away. Eye doctors will use a chart consisting of letters during the test, which is also referred to as distance visual acuity testing.
While there are different variations of the eye chart, the most commonly used one consists of eleven rows of capital letters with the top row containing just one letter and the remaining rows containing more letters that are progressively smaller in size. An eye doctor will ask you to find the smallest line of text letters that you are able to make out and will ask you to read them. If a patient is able to read the bottom row of letters, their sight is considered very good.
Most people have heard of 20/20 vision but may not be familiar with its actual meaning. The standard placement of the chart is on a wall that is 20 feet away from the eyes; however, most doctors’ offices are not this long, so mirrors are used to make the chart appear in front of the patient at this exact distance. If you are able to read the smallest letters on the eye chart from a distance of 20 feet, you have 20/20 vision, which is considered normal. If you are unable to do so, then your visual acuity would be different than that number. For example, if a patient can read the biggest letter at the top of the chart but none of the letters below that, their visual acuity would be 20/200. This would mean they can read at 20 feet a letter that a person with normal vision can read at a distance of 200 feet. Their vision would be considered very poor and the test would determine that their visual acuity is a lot worse than what is considered normal eyesight.
It is important to note that eye charts do have limitations and are used to measure visual acuity only. This test will help your eye doctor figure out whether you need prescription eyeglasses or contact lenses for your distance vision but the chart will not measure the patient’s peripheral vision, depth and color perception, or ability to perceive contrast. Good results on an eye test do not always mean your eyes are healthy, so keep that in mind. Other issues like glaucoma, dry eyes, eye pressure, and the condition of your retinas cannot be determined through this test either, so the chart will not provide you with answers regarding every aspect related to the health of your eyes.
Orangeville Optometric Centre can conduct eye tests for you and can help with all of your eye care needs. Whether you need contact lenses, eyeglass frames, an eye exam, or laser eye surgery, we can help, so if you are looking for a reputable optometrist in the Orangeville area, give us a call today!