You can get a useful snapshot of your vision at home using a few simple tools: a printed eye chart, a tape measure, and good lighting. Home tests can check your distance vision, near vision, and even screen for early signs of eye disease. They won’t replace a professional exam, but they can help you track changes between appointments and catch problems early.
What You Need Before You Start
Pick a well-lit room without windows on the wall you’ll use for the chart. Overhead lighting or a lamp should illuminate the chart evenly. You’ll also need a tape measure, a chair, a flashlight (helpful for directing light onto the chart), and something to cover one eye. A paper cup or your palm works fine. The key rule: always test each eye separately, and always keep both eyes open while covering one.
If you wear glasses or contact lenses for distance, keep them on during the distance test. If you wear reading glasses, keep them on for the near vision test. You’re testing how well you see with your current correction, not your uncorrected eyesight.
Testing Distance Vision With a Snellen Chart
The standard letter chart you’ve seen in every doctor’s office is called a Snellen chart, and you can print one for free from several medical websites. Tape or pin it to the wall at eye level as you sit in a chair. Measure exactly 10 feet from the wall and place your chair at that spot.
Cover your right eye first and read the chart with your left, starting from the top line and working your way down. Go until the letters become too difficult to make out. A line counts as “read correctly” if you get more than half the letters right. Write down the number printed beside the smallest line you could read. Then switch: cover your left eye and test the right.
The numbers on the chart correspond to standard visual acuity scores like 20/20 or 20/40. A result of 20/40, for example, means you need to be 20 feet away to read what someone with normal vision can read at 40 feet. If either eye scores 20/40 or worse, or if there’s a noticeable difference between your two eyes, it’s worth scheduling a professional exam.
Testing Near Vision
Near vision is what you use for reading, cooking, scrolling your phone. To test it, print a near vision chart (sometimes called a Jaeger chart) and hold it exactly 14 inches from your face in good lighting. Wear your reading glasses if you normally use them.
Just like the distance test, cover one eye at a time and read from the largest text down to the smallest you can manage. The chart maps font sizes to Snellen equivalents: the smallest standard print (labeled J1) corresponds to 20/20 at 14 inches, while the largest (J16) corresponds to 20/200. If you struggle to read standard book-sized text, roughly J4 or 20/40, that’s a sign your near vision may need correction.
Checking for Macular Problems With the Amsler Grid
The Amsler grid is a simple square of evenly spaced horizontal and vertical lines with a dot in the center. It’s designed to catch early changes from macular degeneration and other conditions that affect the central part of your retina. The American Academy of Ophthalmology recommends using it once a day if you’ve been diagnosed with or are at risk for age-related macular degeneration.
Wear your reading glasses, hold the grid 12 to 15 inches from your face, and cover one eye. Stare directly at the center dot. Without moving your focus from that dot, pay attention to the lines in your peripheral vision. You’re looking for anything abnormal: lines that appear wavy, areas that look blurry or dark, or blank spots where the grid seems to disappear. Test both eyes separately.
If any part of the grid looks wavy, blank, or distorted, contact an eye care provider right away. These changes can signal fluid buildup or new blood vessel growth in the retina, conditions that respond much better to treatment when caught early.
Testing a Young Child’s Vision
Children ages 3 and older can be screened at home using a “Tumbling E” chart, which replaces letters with the letter E rotated in four directions. The child points (or holds up their hand) in the direction the E’s “legs” are facing, so they don’t need to know the alphabet.
Set up the same way as an adult test: chart at eye level, child seated 10 feet away, one eye covered without pressing on it. Start with the largest E and work down. Make sure the child isn’t peeking around the cover. Record the smallest line where they get more than half correct, then test the other eye. Practice a few rounds before the real test so the child understands what you’re asking.
For children younger than 3, reliable home testing is difficult. Signs to watch for instead include consistently sitting very close to screens, squinting, tilting the head to one side, or one eye drifting inward or outward.
Smartphone Apps for Vision Screening
Several free apps offer digital versions of these same tests. Peek Acuity (Android) measures visual acuity on your phone and includes equivalents of the “count fingers” and “hand movement” assessments used in clinics. Verana Vision Test (iOS) tracks your vision over time using a built-in Amsler grid. EyeXam (Android) bundles acuity testing with checks for astigmatism, color perception, and eye dominance.
More specialized tools exist too. CRADLE White Eye Detector uses your phone’s camera to scan photos of children for an abnormal white reflection in the eye, which can be an early sign of retinoblastoma or other conditions. RetinaRisk helps people with diabetes estimate their risk of developing diabetic retinopathy based on personal health data.
These apps are useful for monitoring trends between professional visits, but they can’t measure eye pressure, examine the back of your eye, or check for conditions like glaucoma that have no symptoms in early stages. Think of them as an alert system, not a diagnosis.
Common Mistakes That Skew Results
The most frequent errors are small but meaningful. Testing at the wrong distance is the biggest one: even a foot or two off from the standard 10 feet will make your results inaccurate. Use a tape measure, not a guess. Dim or uneven lighting makes letters harder to read and can make your vision seem worse than it is. Pressing on the covered eye distorts vision in that eye when you switch sides. And squinting artificially sharpens focus through a pinhole effect, so if you catch yourself doing it, relax your face and try again.
Also test each eye individually, not just both together. Many people have one eye significantly weaker than the other without realizing it, because the stronger eye compensates when both are open.
Symptoms That Need Immediate Attention
Home vision tests are useful for gradual changes, but certain symptoms shouldn’t wait for a screening. Sudden loss of vision in one or both eyes, a burst of new floaters or flashing lights, double vision, eye pain accompanied by nausea or headache, and pupils that are noticeably different sizes all warrant urgent care. These can be signs of retinal detachment, acute glaucoma, or stroke, all of which have much better outcomes with fast treatment.