Visual Efficiency Evaluation: Accommodation

Question 1

What are the two ways to change a dioptric stimulus?

Answer 1

Change the target distance, or change the lenses in front of the patient.

Question 2

Hofstetter’s minimum predicts the minimum accommodation a person should have based on their age (as measured by the push up amplitude). What is this equation?

Answer 2

15 - 0.25(age)

Question 3

During a minus lens method for evaluating accommodative amplitude, how would you determine the patient’s amplitude?

Answer 3

Combine all dioptric demands (lenses in front of the patient, refractive error, target distance, etc)

Question 4

Accommodative amplitude can be measured monocularly, in which case it is considered an absolute value. Which tests are used for this?

Answer 4

Donder’s push up amplitude, minus lens amplitude

Question 5

Accommodative amplitude can be measured binocularly, in which case it is considered a relative value (meaning that vergence is influencing the accommodative system). Which tests are used for this?

Answer 5

PRA, NRA

Question 6

The primary effect of PRA is to ________ (increase/decrease) accommodation, and the secondary effect is to relatively ________ (converge/diverge).

Answer 6

increase accommodation, relatively diverge

Question 7

The primary effect of NRA is to ________ (increase/decrease) accommodation, and the secondary effect is to relatively ________ (converge/diverge).

Answer 7

decrease accommodation, relatively converge

Question 8

Per Dr. Cooper’s slides, NRA has a recommended goal of what for the blur out? Below what value would the NRA be considered a problem?

Answer 8

Goal: +3.00 blur out
Problem: less than +2.50 blur out

Question 9

Accommodative accuracy can be assessed with which tests?

Answer 9

Crossed cylinder, MEM

Question 10

What is the binocular norm for crossed cylinder testing? Monocular norm?

Answer 10

Binocular: +0.75 to +1.25
Monocular: +1.00 to +1.50

Question 11

What range of values are considered normal for MEM?

Answer 11

Plano to +0.75

Question 12

In testing for accommodative facility with plus/minus flippers, what value is the cutoff for normal values for young adults? Give both binocular and monocular cutoffs.

Answer 12

Binocular: less than 6 cpm is abnormal
Monocular: less than 10 cpm is abnormal