Someone with "20/30 vision" stands 20 feet from a reading chart but sees letters and objects that people with normal vision see 30 feet away from the chart, according to the University of Iowa. The first number, 20, is the distance from the eye chart and the second number, 30, shows the size of the letters read at that distance.Know More
A patient with 20/30 vision may need corrective lenses to see properly. The University of Iowa also explains that about 35 percent of Americans have 20/20 vision, meaning they see things normally. Having 20/20 vision describes someone who has sharp, clear vision at a distance. The American Optometric Association explains that other factors including depth perception, peripheral vision and color discernment determine a person's overall seeing ability.
The ability to see from a certain distance is measured by an eye chart hanging on a wall. The chart has 11 rows of letters, with a large "E" at the top. A patient able to read the "E" and nothing else on the chart has 20/200 vision, according to All About Vision. Having 20/200 vision is the definition of legal blindness in the United States. Drivers of vehicles need to have at least 20/40 visual acuity with corrective lenses. The line of 20/20 vision is the fourth row from the bottom of the chart. If a person can read the very bottom line of the chart, that person has 20/5 vision.Learn more about Vision
Health care professionals test visual acuity by evaluating how well a patient can see letters on a chart from different distances, states Healthline. The Snellen test is one common format that involves reading rows of letters or symbols of various sizes from a chart positioned 14 to 20 feet away.Full Answer >
Blurred vision in one eye can be caused by a variety of factors that include eye strain, infections, eye allergies and sleepiness, according to All About Vision. Blurry vision or darkness in one eye can also indicate severe medical or vision issues, such as stroke or retinal detachment.Full Answer >
According to Healthline, blurred vision can signify a variety of conditions such as cataracts, nearsightedness, injuries to the cornea, glaucoma and eye infections. Blurry vision can also occur in individuals with diabetes or as a result of the natural aging process. It is important for anyone experiencing unexplained symptoms of blurred vision to consult with a vision specialist to ensure an accurate diagnosis.Full Answer >
A person with 20/30 vision probably doesn't need glasses, according to EyeCare of East Texas. A determination of 20/30 acuity means that a person sees at 30 feet away from an object what average people see at 20 feet away.Full Answer >