7-8 NRA/PRA

Question 1

What’s the purpose of NRA and PRA? (2)

They’re done to determine the limits of the near zone of clear ____________ vision.

Answer 1

Assess the patients Fusional vergence and accommodative convergence

Binocular

Question 2

When NRA and PRA are measured, what remains constant while the accommodative demand changes?

Answer 2

Convergence demand remains constant

Question 3

Negative relative accommodation is measured using ______ lenses. Causes accommodation to ______ and the eyes will _______.

What’s the expected value range for NRA?

Answer 3

Plus (+)
Relax
Diverge

+2.00 to +2.50

Question 4

If the NRA > +2.50 the patient is over ___________ in the distance

Answer 4

Minused

Question 5

The positive relative accommodation is measured using _______ lenses. Causes the eyes to _______. You start with the patient’s rx then start adding in these lenses (BOTH EYES)

Answer 5

Minus (-) lenses

Converge

Question 6

What’s the near triad- accommodative reflex? (3 things)

What three things reverse accommodative reflex?

Answer 6

Increased accommodation
Convergence
Miosis

Relaxed accommodation
Divergence
Mydriasis

Question 7

For NRA, you add _____ lenses. The chart is at ___cm and you start with 2.5D accommodation. This will _________ accommodative demand!

The opposite is true for PRA :)

Answer 7

PLUS. 40cm. REDUCE

Question 8

What’s the definition of NPC?

Used to measure patients ability to converge the eyes while maintaining fusion on a moving target

Answer 8

Point of intersection of the lines of sight when the eyes are maximally converged