How to Coduct an Eye Exam With a Snellen Chart
Snellen charts, are charts with letters ranging from huge to tiny often seen in doctor's offices and hospitals. They are a common way to roughly determine a person's ability to see, which is referred to as "visual acuity". These are measured by what a person with normal eyesight can see at 20 feet; a fairly simple eye exam using the Snellen chart can thereby determine a patient's visual acuity measured against normal eyesight at 20 feet.
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Instructions
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Before Conducting Exam
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1
Place the Snellen chart on a wall that is in an area with at least 20 feet of clear space looking onto it.
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2
Measure 20 feet from the wall the chart will be placed on. Ensure there will be no obstacles in the way and that the chart is head on.
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3
Mark a line on the ground for patients to stand on.
The Eye Exam
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4
Bring a patient to the marked line.
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Have the patient cover one eye with the eye cover and read aloud every letter in the chart. If the patient misses only one letter, have the patient continue reading the next line.
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6
Record the last line the patient reads accurately, and note what the vision is. Visual acuity measures are marked on the Snellen Chart.
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Ask the patient to repeat the process with the other eye, and then with both eyes uncovered. Both times, record the last line the patient can read accurately.
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8
Record the visual acuity for each eye and with both eyes uncovered. These roughly measure the patient's eyesight.
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Tips & Warnings
Snellen charts are available with both letters and pictures. If a patient is unable to read, have them use the picture chart.
Ensure that the patient will be 20 feet away from the eye chart and will not be interrupted by people passing by.
