Medical Assistant Prep / Unit 14 MAS 338 short lesson, about 20 seconds
The Snellen Chart
Captions available
The idea
Distance vision is commonly screened with a Snellen chart, read from twenty feet away.
In practice
A result of twenty over twenty is normal; twenty over thirty means the patient sees at twenty feet what a person with normal vision sees at thirty.
Where people slip
The larger the second number, the poorer the distance vision.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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