What Is an Eye Chart?
An eye chart is a chart comprising multiple rows of single letters in decreasing order of size. The eye chart measures the visual acuity or in simpler words, how well you see with both of your eyes. So if you notice poor vision in one or both of your eyes, your eye care specialist will evaluate your vision with the standard eye chart. Snellen chart is the most frequently used eye test chart.
Your vision is usually the first test your eye care professional does. It also provides the most important basic information about the health status of your eyes.
Eye charts not only help determine the vision in the initial eye examination, they also help in assessing the response to various treatments for eye diseases.
Download and Print the Eye Chart
You can download the Snellen eye chart from visionsource.com by clicking here (opens in new tab/window).
Alternatively, you can download the vision chart here.
Make sure you print it in letter-size. Click here to find out the difference between A4 and letter-size.
How to Use the Eye Chart
- Paste or tape the paper on a wall at eye level. The wall should be well-illuminated.
- Sit or stand 10 feet away from the eye chart. For a normal Snellen eye chart, the distance at which your read the chart is 20 feet but the chart you have printed is smaller in size. The size of letters on your eye chart at ten feet is the same as the size of letters on a normal-sized eye chart at a distance of 20 feet.
- Cover your left eye with your palm. Read the letters with your right eye. Note down the line up to which you can read. If you are able to read majority of letters in line 8, your vision is 20/20 or 6/6.
- Now cover the right eye and repeat the same steps with the left eye.
Interpretation of Vision Test
What does it mean to have 20/20 (or 6/6) vision? You will understand it better if you know what it means to have 20/200 (or 6/60) vision.
20/200 means you can read that line (and not beyond that) at a distance of 20 feet which a normal individual would be able to read at a distance of 200 feet. 20/20 means you can read that line at a distance of 20 feet which a normal person would read at the same distance implying that 20/20 vision is normal.
What an Eye Chart Cannot Test
Eye charts are used to assess visual acuity only.
Eye charts do not test your visual field. They test only your central vision (and not the peripheral vision). For example, in case of advanced glaucoma and retinitis pigmentosa, the central vision may be normal while the peripheral vision may be severely impaired.
Eye charts do not test color vision. A color-blind person can generally read 20/20 line if there are no other coexisting abnormalities of the eye.
They also don’t test the eye pressure or intraocular pressure, the health of retina, mild infections and inflammation of the eye and so on.
Eye chart testing is one of the most critical components of a comprehensive eye examination. If your vision is less than 20/20 (or 6/6), you will most probably need glasses or contact lenses. If the vision in one or both eyes is 20/200 or less, the cause of poor vision may be a serious one.
Whatever the case, if your vision is poor on eye chart testing, you must consult an optometrist or ophthalmologist for a more detailed eye examination to know its cause and find a solution.
Photo by kenteegardin