1. Control accommodation by stressing the importance of keeping the target clear.

2. Stress the importance of trying to keep the target clear and single for as long as possible.

1. If the patient wears glasses for close work, these should be used.

2. Hold Gulden fixation stick tongue depressor 40 cm from patient’s face at eye level.

1. Say the following: “I want you to look at the letter on this stick. When I place this measuring device in front of your eye, you will see double. Try to get the target to be clear and one as soon as possible. Say ‘now’ as soon as it is clear and one.”

2. Begin with either base-out or base-in and count how many cpm the patient can complete in 60 seconds (one cycle equals successful completion of both base-out and base-in).

3. Record the number of cpm.

4. If the patient cannot do either base-in or base-out, record as 0 cpm, fails base-out or base-in.

5. If the patient cannot do both, record as 0 cpm, cannot do base-in or base-out.

1. The patient can complete 18 flips in 1 minute. This equals 9 cpm.

2. If the patient cannot regain single and clear vision at all, record as 0 cpm, fails both base-in and base-out.

3. If the patient cannot regain single and clear vision with base-in, record as 0 cpm, fails base-in.

4. If the patient cannot regain single and clear vision with base-out, record as 0 cpm, fails base-out.

1. Control accommodation by stressing the importance of keeping the target clear.

2. Stress the importance of trying to regain clear and single vision as quickly as possible.

1. Seat the patient comfortably behind the phoropter with the patient’s distance correction in place.

2. Place the near point card at a 40-cm distance from the patient, with good illumination.

1. Instruct the patient to look at the target and keep it clear and single.

2. Instructions: “I will be changing the lenses in front of your eyes. Try to keep the line of letters clear and single for as long as you can. Tell me as soon as the letters become blurry or double.”

3. Add plus lenses in +0.25 D increments until the patient reports the first sustained blur or diplopia.

4. Record the amount of plus added above the distance prescription as the NRA.

5. Remove the plus lenses and return to the distance prescription.

6. Add minus lenses in −0.25 D increments until the patient reports the first sustained blur or diplopia.

7. Record the amount of minus added above the distance prescription as the PRA.

8. Stop the PRA test when you reach −2.50 D above the distance prescription.

1. Stress the importance of reporting both blur and diplopia.

2. Discontinue the PRA at −2.50 D.

1. If the patient wears glasses for close work, these should be used.

2. Hold Gulden fixation stick tongue depressor 40 cm from patient’s face at eye level.

3. Ask the patient to look at the isolated 20/50 target on the Gulden fixation stick.

1. Slowly move the fixation stick toward the patient at eye level and between the two eyes.

2. Ask the patient to keep the target one for as long as possible.

3. Ask the patient to tell you when he or she sees two targets.

4. Once diplopia occurs, move the fixation stick in another inch or two and then begin to move it away from the patient.

5. Ask the patient to try and see “one” again.

6. Also watch the eyes carefully and observe whether the eyes stop working together as a team (one eye will usually drift out).

7. Record the distance at which the patient reports double vision and when the patient reports recovery of single vision.

8. Repeat the test using a penlight and red/green glasses if you suspect that dissociation may reveal a more receded NPC.

1. Repeat the test several times if results are not definitive.

2. Watch the patient’s eyes and try to objectively determine when the break and recovery occur.