Skip to main content
Menu

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!

In an effort to further protect our patients and staff, we are taking the following precautions at our office:

When you arrive in the office for your appointment:

  1. The door will remain locked and open only for patients that have been initially screened
  2. Careful Screening:  All persons entering the office will be screened for symptoms of COVID-19 by 1) being asked a series of screening questions and 2) their temperature will be taken before entering the office.  If the patient's temperature is greater or equal to 100.4 degrees F (38 degrees C), that person will be denied entrance and asked to see their primary care physician.
  3. No additional family, friends, etc will be allowed to accompany the patient into the office
    1. *Exception: children and others requiring assistance - 1 single parent or accompanied guardian allowed
  4. We ask that you please wear cloth or medical MASKS when entering our office. A mask will be required for entry through the door.
  5.  We will be implementing a *$50 “No Show Fee”* for no shows or cancellations if we are not notified at least 24 hours prior to your scheduled appointment.

Safety and Sanitization Precautions:

Frame Selections, Adjustments, Repairs and Dispensing:

 

Although there may be some changes to your normal visit to our office, we assure you that we are doing our best to follow all CDC, California Department of Public Health, California Optometric Association and local public health guidelines to keep our patients, staff and community safe without compromising our standard of excellence and quality during this time.

We ask that you all are mindful of the following precautions. We are all in this together. We look forward to SEEing you all soon!

Aloha Family Optometric Team