When you go to the optometrist there are several different eyesight charts that you may be asked to read. Some of them test one eye at a time and others will require you to use both of your eyes as your regularly do. Fortunately, they are painless and most of them take only a few minutes to complete. Read on for an overview of eyesight charts that you may expect during your visit.
Visual Acuity Eye Charts
The Snellen test checks your ability to see at a distance and is an eyesight chart that has different rows of letters with the top row of letters being largest and the bottom row of letters being the smallest. Your doctor will position you 20 feet away from the chart and have you read the rows until you can’t see to read any more and each eye is tested separately. To keep you from cheating from memory, you may be given different charts for each eye.
The E Chart is an eyesight chart that does the same thing as the Snellen chart except for it is used for children and people that can’t read. The rows are the same as the Snellan chart in that they start big and get smaller as the rows go down, but the only letter on the E Chart is an E that is positioned differently throughout the row.
The patient simply has to say which direction the E is pointing. With either of these tests, you should tell the doctor if you have problems seeing the letters on the edge or if letters disappear while you are looking at others because you may have visual field problems.
The Near Test is another eyesight chart that does exactly what it says it does; it checks your near vision. There are rows of text printed on a card that gradually gets smaller as you read down the card. You will be asked to read down the card until you can’t read anymore. Both of your eyes are tested at once during this test and you may or may not be asked to take off your glasses if you wear any.
Visual Field Eye Chart
The Amsler grid test is an eye chart used to check for macular degeneration. It’s a grid of lines that form boxes and each box has a dot in the middle. The chart will be held about 14 inches in front of you and you’ll have to cover one eye and stare at the dot. Then he’ll repeat it on the other eye. You should tell the doctor if the dot disappears, the lines appear wavy or you see a blank or dark spot instead of the dot. These may be signs that you have macular degeneration.
Color Vision Eye Chart
These eye charts are made up of different colored dots that check for various forms of color blindness. There will be numbers, shapes and letters in one color or a series of colors surrounded by a background of dots in other colors. The charts are easy to read for people with regular vision but people with color blindness won’t be able to discern the patterns.
Eye charts have been used since the time that doctors starting testing eyes. Though they are low tech, the are accurate and do the job that they are meant to do. The eye charts are painless and effective and take very little time, so for once, you don’t have to dread going to a doctor’s appointment!