Клиническое ведение нарушений бинокулярного зрения: гетерофории, аккомодационные и глазодвигательные расстройства

1. It is critical to control accommodation for both measurements by stressing the importance of keeping the target clear.

Phoropter

Near point card with a vertical line of 20/30 letters

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.
3. Place the Risley prisms before both eyes and set both Risley prisms at zero; position the Risley prism so that you can introduce horizontal prism.

1. Instruct the patient to open both eyes and ask how many targets he or she sees. The patient should see one target. If the patient reports diplopia, add either base-in or base-out until fusion occurs. This will be the starting point for the test.
2. Ask the patient to look at the target and keep it clear and single.
3. Instructions: “I will be changing the lenses in front of your eyes. Try to keep the line of letters single and clear for as long as you can. Tell me as soon as the letters become blurry or double.”
4. Introduce base-in at about a rate of 2Δ per second.
5. Record the amount of prism when the patient reports blur (blur).
6. Continue to add base-in prism until the patient reports double vision (break).
7. Continue 2 to 4 Δ past the breakpoint and then begin reducing the base-in prism until the patient reports single vision again (recovery).
8. Repeat steps 4 to 7 with base-out prism.
9. This sequence can also be repeated at distance, if there is concern about a distance binocular vision disorder. Repeat steps 1 to 8 using an isolated 20/30 target set at 20 ft.

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.

Phoropter

Near point card with a horizontal line of 20/30 letters

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.
3. Place the Risley prisms before both eyes and set both Risley prisms at zero; position the Risley prism so that you can introduce vertical prism.

1. Instruct the patient to open both eyes and ask how many targets he or she sees. The patient should see one target. If the patient reports diplopia, add either base-in or base-out until fusion occurs. This will be the starting point for the test.
2. Ask the patient to look at the target and keep it clear and single.
3. Instructions: “I will be changing the lenses in front of your eyes. Try to keep the line of letters single for as long as you can. Tell me as soon as the letters double.”
4. Introduce base-up before the right eye only (right infravergence) at about a rate of 2 Δ per second.
5. Record the amount of prism in place when the patient reports double vision (break).
6. Continue 1 to 2 Δ past the breakpoint and then begin reducing the base-up prism until the patient reports single vision again (recovery).
7. Repeat steps 4 to 7 with base-down (right supravergence) prism.
8. This sequence can also be repeated at distance, if there is concern about a distance binocular vision disorder. Repeat steps 1 to 8 using an isolated 20/30 target set at 20 ft.

1. Stress the importance of trying to keep the target single for as long as possible.

Prism bar

Gulden fixation stick (20/30 target)

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 might see blurry or double. Keep looking at the letter; try to keep it single and clear, but tell me when it becomes blurry or double.”

Begin with base-in prism in front of the right eye. Increase the amount of prism in front of the right eye at approximately 2 Δ per second, stopping when the target moves laterally or breaks.

3. Always begin with the prism bar above the eyes and slowly move the prism bar down, increasing the base-in or base-out demand. When the patient reports blurred vision, mentally record the prism value.
4. Continue adding prism until the patient reports double vision and mentally record the prism value.
5. Continue to increase the base-in demand by about five more prism diopters and then, at a rate of about 2 Δ per second, reduce the base-in prism until the patient regains single vision (it does not have to be clear). Mentally record the prism value.
6. Record as a blur finding, a break finding, and a recovery finding. Example: 6/12/8. This means that the patient reported blurred vision at 6 Δ, double vision at 12 Δ, and single vision at 8 Δ.
7. Now repeat with base-out prism.