Relative Accommodation

Question 1

What does relative accommodation test the ability of?

Answer 1

The ability for your patient to both relax (NRA) and stimulate (PRA) accommodation while maintaining single, binocular vision.

Question 2

What do you do to find NRA? What does this cause?

Answer 2

You add plus lenses by 0.25D steps until the patient reports sustained blur of the target at 40 cm. It causes decreased accommodation and subsequently affects accommodative and fusional vergence.

Question 3

For a presbyope, what must you begin with when doing NRA?

Answer 3

You must begin with a near control lens that is the total of MR and bifocal add as the beginning point since the presbyope will be blurred at 40 cm through manifest refraction.

Question 4

What sign does a net NRA always have?

Answer 4

Positive sign

Question 5

What sign does a net PRA always have?

Answer 5

Negative sign

Question 6

On NRA, the patient will need to employ _____________ vergence to counter the reduction in accommodation and accommodative convergence (which leads to a shift toward _________)

Answer 6

positive fusional; exophoria

Question 7

On PRA, the patient will need to employ _____________ vergence to counter the increase in accommodation and accommodative convergence (which leads to a shift toward _________)

Answer 7

negative fusional; esophoria

Question 8

For NRA, what lenses do you use? Does accommodation increase or decrease? Does positive fusional vergence increase or decrease?

Answer 8

For NRA, use plus lenses, decrease accommodation, increase PFV

Question 9

For PRA, what lenses do you use? Does accommodation increase or decrease? Does negative fusional vergence increase or decrease?

Answer 9

For PRA, use minus lenses, increase accommodation, increase NFV

Question 10

The amount of the net NRA is determined by two factors:

Answer 10

1) The amount of accommodation that was relaxed for the test stimulus
2) The amount of Positive Fusional Vergence available to the patient, as measured by the Base Out vergence

Question 11

How much does the depth of focus add?

Answer 11

0.50D

Question 12

When can a problem arise when testing negative accommodation?

Answer 12

1) If the patient is highly exophoric with a normal AC/A, the patient may go diplopic before the blur point. If this happens, record the point at which the diplopia occurs and note the value was diplopia.
2) If more than 3.00D of plus is added over the manifest refraction, the patient could be over minused on the manifest refraction.

Question 13

Exophoric patient usually have ___ AC/A.

Answer 13

Low

Question 14

What does NRA measure?

Answer 14

measures the amount of accommodation that can be relaxed relative to convergence (increase in NAV and subsequent need for more PFV)

Question 15

The amount of the net PRA is determined by two factors:

Answer 15

1) The accommodative amplitude of the patient.

2) The amount of negative fusional vergence available to the patient, as measured by the Base In vergence

Question 16

Problem that can occur with positive relative accommodation

Answer 16

If the patient is highly esophoric, the patient may go diplopic before the blur point. If this happens, record the point at which the diplopia occurs and note the value was diplopia.

Question 17

Highly esophoric patients usually have ___ AC/A.

Answer 17

high

Question 18

When does the blur occur for PRA?

Answer 18

the blur occurs when accommodation is fully stimulated or when the patient runs out of NFV.

Question 19

When does the blur occur for NRA?

Answer 19

the blur occurs when accommodation is fully relaxed or when the patient runs out of PFV.

Question 20

If tests are run monocularly, what is the only thing being tested?

Answer 20

Accommodation

Question 21

Doing PRA testing for a bino exophore, would the patient like or not like the minus given?

Answer 21

Exo would like the minus given in PRA because it helps relax exophoria.

Question 22

Doing PRA testing for a bino esophore, would the patient like or not like the minus given?

Answer 22

Not like. It would make the esophoria worse.

Question 23

Doing PRA testing for a monocular esophore, would the patient like or not like the minus given?

Answer 23

Help if the results were limited by NFV instead of accomodation.

Question 24

Doing NRA testing for a monocular esophore, would the patient like or not like the plus given?

Answer 24

No change

Question 25

Doing NRA testing for a monocular exophore, would the patient like or not like the plus given?

Answer 25

They would like it. It would help if their eyes were limited by PFV instead of accomodation.

Question 26

Doing NRA testing for a binocular esophore, would the patient like or not like the plus given?

Answer 26

They would like it because it helps their eso. They would have higher number.

Question 27

Doing NRA testing for a binocular exophore, would the patient like or not like the plus given?

Answer 27

Not like the plus and take less. It makes exophoria worse

Question 28

For PRA, an exophore has to become _______ before running out of the predicted AC/A endpoint

Answer 28

esophoric

Question 29

For PRA, a __________ is more likely to run out of accommodation amplitude than negative fusional vergence.

Answer 29

exophore

Question 30

For NRA, what values do you use and look at for near testing?

Answer 30

Use PFV, BO testing.

Question 31

For PRA, what values do you use and look at for near testing?

Answer 31

Use NFV, BI vergence testing

Question 32

What is always the predicted accommodative amplitude for NRA testing?

Answer 32

+ 2.50 D

Question 33

How to find the predicted accommodation endpoint for PRA testing?

Answer 33

Accommodation amplitude - 2.50D (from stimulus)