Doctors normally perform eye tests in an office, but it is possible to administer a test in the privacy of your home. Eye tests involve reading letters of different size off a chart called the Snellen chart. You stand 20 feet away from the chart and read as many letters as possible. Where you stop reading determines your vision acuity, which helps optometrists know whether you have a vision disorder. While performing the test at home is possible, you also need a prescription from an eye doctor, and you receive a comprehensive consultation that goes over symptoms of eye diseases.
Hang a Snellen chart on an empty wall in a well lit room (see "Resources"). Hang the chart at eye level and attach it to the wall with tape.
Measure 20 feet from the chart using measuring tape. Mark this spot on the floor using a piece of tape. Stand at this point.
Cover one eye with a piece of paper or a wash cloth.
Read each line of the chart out loud. Have someone stand next to the chart to see if you read the letters correctly. Read the letters until they become to difficult to see. Write down the last line you easily read aloud.
Repeat the process with the other eye.
Approach the chart and note the number next to the line of letters you were last able to read. This is your visual acuity number. If the number is 20/20 then you have normal vision. If the number is 20/40, then your vision is half of normal vision, meaning that you only see objects clearly at 20 feet, whereas other people see at 40 feet.
Consult an eye doctor if the results worry you. Schedule yearly appointments with an optometrist to catch any vision loss or illness.