Difference between revisions of Visual acuity
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→Reading a Snellen chart
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* 20/10 is excellent. | * 20/10 is excellent. | ||
The [[prescription]] for [[myopes]] and [[hyperopes]] is typically the weakest lens power required to achieve 20/20 or better vision measured at [[distance vision|20 feet or 6 meters]]. The prescription for a [[presbyope]] is the smallest plus power added to the distance prescription to see 20/20 at 40 cm. | The [[prescription]] for [[myopes]] and [[hyperopes]] is typically the weakest lens power required to achieve 20/20 or better vision measured at [[distance vision|20 feet or 6 meters]]. The prescription for a [[presbyope]] is the smallest plus power added to the distance prescription to see 20/20 at 40 cm. Emmetropic presbyopes have zero distance prescription, so their near prescription is simple spherical [[plus lenses]]. | ||
===Caveats=== | ===Caveats=== | ||