Positive relative accommodation
Positive relative accommodation (PRA) in
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.
High PRA values (>= 3.50
diopters) are considered to be diagnostic of disorders involving accommodative excess.[2] Those with accommodative insufficiency typically have PRA values below −1.50 diopters.[3]
See also
- Accommodation in fish
- Adaptation (eye)
- Amplitude of accommodation
- Convergence insufficiency
- Mandelbaum effect
- Negative relative accommodation
References
- ^ www.vision-therapy.com Archived December 8, 2005, at the Wayback Machine
- S2CID 31075351.
- ^ "Care of the Patient with Accommodative and Vergence Dysfunction" (PDF). Archived from the original (PDF) on May 10, 2006. Retrieved May 8, 2006.