The Year of the Eyeball

It is January 19, and I realized that I never posted about the New Year! Happy New Year to everyone. Welcome to the year of the eyeball, 2020.

Sometimes people tell me that they don’t know what is better vision when they hear vision measurements like 20/25 or 20/15. The second number represents the distance in feet from which you are “supposed” to be able to see the letter. This is based on average human vision with the correct glasses on. The first number is usually 20 because “true” ophthalmology exam rooms place the chart 20 feet away from the patient. Therefore, if the patient can see a letter on the chart from 20 feet away but the letter is “supposed” to be seen from 25 feet, then the vision is 20/25. If a different letter is “supposed” to be seen from 15 feet but the patient can see it from 20 feet, the vision is 20/15. That means that 20/15 vision is better than 20/25 vision, i.e. the lower second number indicates better vision.