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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!

Hello Patients,

Thank you for your patience and understanding in this incredibly challenging situation. Starting 3/18, we are going to be open from ~9-5 for ordering contact lenses as well as dispensing glasses and contact lens orders we have received. No patients will be coming in to the office tomorrow, and our doors will remain locked during business hours. If you are having an ocular emergency, please contact the office at 925-283-8502 and we will be happy to assist you.

We are going to be doing "zero interaction" contact lens and glasses dispensing. If you have been notified that your eyewear or contacts are ready, please call the office for instructions on picking them up. Since we are closed to the public, we are dispensing contacts and glasses by appointment only. We are doing this to maintain social distancing and keep you safe!

Finally, on a personal note, if you need contact lenses or have flex spending you need to utilize, please think of our office first. We can directly ship items to you, no need to leave your house. We truly appreciate your support.

Best regards,

Nathan Orr, O.D.

Hello Patients,

Thank you for your patience and understanding in this incredibly challenging situation. Starting 3/18, we are going to be open from ~9-5 for ordering contact lenses as well as dispensing glasses and contact lens orders we have received. No patients will be coming in to the office tomorrow, and our doors will remain locked during business hours. If you are having an ocular emergency, please contact the office at 925-283-8502 and we will be happy to assist you.

We are going to be doing “zero interaction” contact lens and glasses dispensing. If you have been notified that your eyewear or contacts are ready, please call the office for instructions on picking them up. Since we are closed to the public, we are dispensing contacts and glasses by appointment only. We are doing this to maintain social distancing and keep you safe!

Finally, on a personal note, if you need contact lenses or have flex spending you need to utilize, please think of our office first. We can directly ship items to you, no need to leave your house. We truly appreciate your support.

Best regards,

Nathan Orr, O.D.