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Understanding the Eye Chart

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Eye charts of different variations have become a standard in vision screenings and eye exams. One of the most familiar charts associated with vision is the Snellen eye chart, designed by Dutch ophthalmologist Hermann Snellen in 1862 to measure visual acuity- how well you can see at various distances.

Although there are variations of the Snellen chart used today, a traditional Snellen chart has eleven lines of block letters. The first line has one very large letter, which is one of several letters, for example E, H, or N. The following rows have increasing numbers of letters that become smaller in size as you read from the top to the bottom of the chart. The letters used on the chart are C, D, E, F, L, N, O, P, T, and Z.

When taking a vision exam, one eye is covered and you are asked to read the letters of each row aloud beginning at the top of the chart. The smallest row that you can read correctly indicates the visual acuity in the eye being tested.

The chart is positioned at a distance of 20 feet in the United States or 6 meters in the rest of the world. The term 20/20 vision is used to indicate the clarity and sharpness of your vision measured at a distance of 20 feet. If you have 20/20 vision, you can see clearly at 20 feet objects that can normally be seen at that distance. If you have 20/40 vision, it means that you need to be as close as 20 feet to see what a person with normal vision can see at 40 feet. The largest letter on an eye chart often represents an acuity of 20/200 which is associated with the term "legally blind."

You will be asked to read the letters one eye at a time. Some people can see well at a distance, but are unable to bring nearer objects into focus, while others can see items that are close, but cannot see them far away. By having you read the chart, your eye doctor is able to ascertain whether you have difficulty with distance vision and can determine which corrective lenses can be used to improve it. Near vision problems or other vision and eye health issues may not be detected with the Snellen eye chart alone, so a comprehensive eye exam is always recommended.

The next time you hop into the chair at your optometrists' office, you'll be able to understand why you have to read the letters on the chart in front of you and what the results mean for your vision.

We are opening on a limited basis as of May 4th, 2020!

Although we are open, our doors will remain locked to help manage personal interaction. Call our office at 309-263-8611 to schedule:

Once you arrive for an appointment, call us from our parking lot and we will ensure proper disinfection protocols have been completed before bringing you in. We have implemented strict screening measures and safety precautions in order to protect the health and safety of our patients, staff and community.

Per the CDC's recommendation, we ask that you wear a mask to your appointment. On entering the facilities, a member of our team will take your temperature and ask you a series of COVID-19 related questions. We ask that guests or family members stay in their vehicles to further our efforts to prevent the spread of COVID-19 and to protect our staff and patients.

During this crisis, please consider the CDC’s recommended precautions before, during and after your visit:

In addition to implementing safety measures for our patients, we will also be implementing screening protocols for our staff. We are closely monitoring the COVID-19 crisis and are following the guidance and expertise of the Centers for Disease Control and Infection (CDC), the state and local public health officials, the Illinois Optometric Association (IOA) and the American Optometric Association (AOA).

If you would like to schedule an appointment, need to reschedule your appointment, or have further questions please contact us at 309-263-8611.

 

Thank you for your patience with us during this time,

Drs. Velting, Sommer, and the entire team at Vintage Optical

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