Positive relative accommodation

Positive relative accommodation (PRA) is a measure of the maximum ability to stimulate accommodation while maintaining clear, single binocular vision. This measurement is typically obtained by an orthoptist, ophthalmologist or optometrist during an eye examination using a phoropter. After the patient's distance correction is established, he is instructed to view small letters on a card 40 cm from the eyes. The examiner adds lenses in −0.25 diopter increments until the patient first reports that they become blurry. The total value of the lenses added to reach this point is the PRA value.

单词	Positive relative accommodation
释义	Positive relative accommodation 英语百科 Positive relative accommodation Positive relative accommodation (PRA) is a measure of the maximum ability to stimulate accommodation while maintaining clear, single binocular vision. This measurement is typically obtained by an orthoptist, ophthalmologist or optometrist during an eye examination using a phoropter. After the patient's distance correction is established, he is instructed to view small letters on a card 40 cm from the eyes. The examiner adds lenses in −0.25 diopter increments until the patient first reports that they become blurry. The total value of the lenses added to reach this point is the PRA value.
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