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What Does An Eye Chart Do?

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Blog

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EyeQue Team

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May 17, 2019

Eyeglasses in front of Snellen eye chart

Chances are, you’ve probably seen an eye chart. Hanging up at your eye doctor’s office, your primary care physician’s office, and even at the nurse’s office in your child’s school, they are everywhere. You may be wondering whether all of these eye charts are the same, and what they actually do.

What Does An Eye Chart Measure?

Eye charts help your eye doctor measure your visual acuity—how sharp or blurry your vision is. Based on your test results using the chart, your eye doctor can tell you whether you need eyeglasses, contact lenses, or another form of eye correction.

What Are the Most Common Types of Eye Charts?

  • Snellen chart — This is the most common type of eye chart, and it’s probably the one you saw at your last eye appointment. The Snellen chart is the only standardized eye chart used by ophthalmologists. It consists of eleven rows of uppercase letters, with the size of the letters decreasing as you move down each row. Usually, you will stand twenty feet away from the chart to find out which lines you can read without corrective lenses.
  • Tumbling E chart — Dr. Hermann Snellen, the eye doctor who developed the Snellen chart, modified his original eye chart so children could take the vision test even if they don’t know their alphabet yet. The Tumbling E chart consists of rows of the capital letter E facing in different directions. A child can point their fingers in the direction of the E to show whether they can properly read the chart.

There are many other non-standardized eye charts, including the ETDRS chart, Landolt C chart, and Lea Symbols, which are used less frequently because they have not been proven to reliably determine visual acuity.

How Can I Test My Visual Acuity?

You no longer have to visit an eye doctor to take an accurate vision test. Check out EyeQue’s home vision testing products. The VisionCheck and Personal Vision Tracker are great for adults and gives you EyeGlass Numbers that you can use to order eyeglasses online. Insight is great for families with children. You can test for visual acuity, contrast sensitivity, and even color blindness.

 

 

Test Your Vision At Home

Use the EyeQue Vision Monitoring Kit to test your refractive error, distance, color and contrast vision – plus a pupillary distance tool.

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