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Optometric Physician

Snellen Chart

Hopefully by now, we’ve all seen one. The projected or wall-mounted Snellen eye chart, usually topped by the big letter “E”, is a common visual acuity test used to measure your sharpness of vision at multiple distances.

Arranged as a pyramid of sorts, the letters in the Snellen chart are specifically chosen and arranged to test your sharpness and clarity of vision at a baseline distance of 20 feet. During a visual acuity test, the Snellen eye chart is viewed as a projection, or mounted on a wall.

Handheld versions of Snellen charts are used for testing near vision as well.

By viewing or reading each line from top to bottom (with one eye covered at a time), your eye doctor can gain a general approximation of the quality of your visual acuity, or sharpness. Where a line of characters begin to become difficult to see is the approximate measurement of your vision.

The Snellen chart serves as a beginning—not an end—to a comprehensive eye examination.

What does “20/20” vision mean?

Snellen charts help to determine a baseline for your vision in each eye—a baseline typically measured against “20/20” vision. This means when you are 20 feet away from an object, you can comfortably see details that most people with normal vision can also see at 20 feet distance.

If you have 20/30 vision, that means what you see comfortably at 20 feet, can be seen by a person with “normal” vision at 30 feet. Your vision is weaker, in other words.

Conversely? In the rare instances where vision may test better than normal on a Snellen chart, a value of 20/10 vision means that you can see clearly from a distance of 20 feet, what a person with normal vision sees well at a distance of 10 feet. Make sense?

In fact, if you look closely at a Snellen eye chart, you’ll see the vision values associated with measuring your vision on the right or left side of each line of characters.

 

Special thanks to the EyeGlass Guide, for informational material that aided in the creation of this website. Visit the EyeGlass Guide today!

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Our Restart

Following the governor’s latest guidance, we will be here for preventative and urgent eye care beginning Monday, May 4th by appointment only. We are committed to quality eye care, and we have put in place the following precautions to keep all of us safe:

  • Staff will wear masks and we ask each patient to wear a mask.
  • If possible, please complete the online history form @ Drarbow.com prior to your examination time.
  • Companions will be asked to wait outside unless needed for mobility or cognition issues.
  • As with staff, patients will have a temperature check and be asked screening questions before they are taken back to the exam room.
  • We have established a schedule to facilitate a “no wait” policy, and we will make every effort to seat the patient upon arrival.
  • We will limit the number of patients in the dispensary. Each frame will be disinfected if handled.
  • UV-C air filters and sanitizers have been placed throughout the office.
  • Enhanced and more frequent cleaning of surfaces and touchpoints has been implemented.

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