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Williams Eye Care - Frisco

2601 Preston Rd.
Frisco, TX 75034

FAIRVIEW APPT | 972-218-0042

Williams Eye Care - Fairview

120 Town Pl.
Fairview, TX 75069

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Home » What's New » Understanding the Eye Chart

Understanding the Eye Chart

eyechart

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.

office update 2 williams eye care

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Because of the COVID 19 Virus we will only be staying open to meet the needs of patients with eye problems and emergency exams.

We will be deferring routine exams and delaying contact lens exams until further notice. We will be supporting our patients who were unable to come for their contact lens exams, due to these new restrictions, by extending your current contact lens prescriptions, whenever possible. Please call to discuss this option with us.

When all is settled, we will be calling our postponed patients to get them back in for those exams.

Patients over the age of 60 or in a high risk category will not be seen so please call ahead and speak to us before you come by.

If you have an emergency or medical issue, call us! We’re here to help!

Thank you so much!!! 972-210-2100