What do the numbers mean on a vision test?
When you look at your prescription for eyeglasses, you will see numbers listed under the headings of OS and OD. They are Latin abbreviations: OS (oculus sinister) means the left eye and OD (oculus dextrus) means the right eye. For example, if your prescription says -1.00, you have one diopter of nearsightedness.
What is the difference between 20/20 Vision and 20 30 vision?
If you have 20/20 vision, based on your eye test, your vision is standard, allowing you to see what the majority of people do from 20 feet away. What does 20/30 vision mean? It indicates that you can observe something at 20 feet that others see from 30 feet away.
What does a 10/40 visual acuity mean?
Using a Snellen Eye Chart From 10 feet, if the smallest letters you could read were on the “40” line, this would give you an acuity of 10/40: 1/4 normal. If you are nearsighted, your vision will become more normal the closer you stand to the chart.
Do I need glasses for 20 50?
20/40 vision uncorrected in at least one eye is the vision required to pass many state driving tests (for driving without glasses). 20/50 vision or worse is often the visual reduction that is considered bad enough by most patients to need cataract surgery, if that is the cause of the visual loss.
What does a 20 30 vision mean?
For example, if you have 20/30 vision, it means your vision is worse than average. Twenty feet away, you can read letters most people see from 30 feet. A standard Snellen vision testing chart.
What line on the eye chart is 20 40?
The third line is equivalent to 20/40, it is the driver’s test line.
What is a good eye test score?
Perfect vision yields a score of 20/20, which means the viewer can see the same letters at 20 feet away what another normal viewer could also see at 20 feet. If your vision is less than perfect, you might receive a score of 20/40 or 20/50.
What is the purpose of a Snellen chart?
Invented in 1862 by a Dutch ophthalmologist named Herman Snellen, the Snellen chart remains the most widespread technique in clinical practice for measuring visual acuity.  The Snellen chart serves as a portable tool to quickly assess monocular and binocular visual acuity.