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Eye and Vision Care

What do 20/60 vision and 2010 vision mean?

01/16/2006

Question:

what does 20/10 vision mean and what does 20/60 vision mean

Answer:

Good question. Eye doctors measure a patient's visual acuity by determining the smallest letter size he or she can read. The way we do this is to show the patient various letter sizes that are calibrated as follows:

The top number is the testing distance (20 means twenty feet away). The bottom number is the distance at which that letter size would measure 5 minutes of angle (60 means sixty feet away; 10 means ten feet away).

20/20 is considered to be normal vision. In layman's terms, a patient who measures 20/60 visual acuity would need to stand twenty feet away from a letter that normal patients could see from sixty feet away.

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Response by:

Robert D Newcomb, OD, MPH, FAAO Robert D Newcomb, OD, MPH, FAAO
Professor Emeritus of Clinical Optometry
College of Optometry
The Ohio State University