Distance Phoria*

Question 1

What is the purpose of subjective phoria testing?

Answer 1

Assess patient’s natural horizontal and vertical eye posture at distance and near

Question 2

What is the illumination for VG?

Answer 2

Dim for distance
Bright for near

Question 3

Is the patient corrected during this test?

Answer 3

Yes, proper distance and near refraction

Question 4

What is the target for VG?

Answer 4

Small accommodative target (distance: single letter 1-2 lines above BCVA (20/30 for 20/20VA), near: small box of letters if patient is 20/20 at 40cm

Question 5

Is distance or near phoria testing performed first?

Answer 5

Distance

Question 6

For the first step of VG what prisms should be placed in front of each eye?

Answer 6

12 BI OD (top image)
6 BU OS (bottom image)

Question 7

What should you ask the patient after placing the prisms?

Answer 7

How many images do you see?

Question 8

What should you do if the patient does not see 2 images?

Answer 8

Place 12 BO OD and ask again

Question 9

After ensuring that the patient sees two images, what should you ask?

Answer 9

Is the top image to the right or the left of the bottom?

Question 10

What should you do if the top image is to the right?

Answer 10

Patient is uncrossed (eso)
Prism should be moved in the direction of BO

Question 11

What should you do if the top image is to the left?

Answer 11

Crossed disparity, expo
Prism should be moved to BI

Question 12

What should you instruct patient as you move the prism wheel?

Answer 12

Let you know when the two images are on top of each other (buttons on a shirt)
Keep focus on bottom stationary image

Question 13

At what rate should the prisms be moved?

Answer 13

2-3 prism D per second

Question 14

How do you bracket?

Answer 14

Move 2-4pD past location where they match up and move back down
Average the results

Question 15

What should be done after finding the phoria for OD?

Answer 15

Reset to 12 BI or 12 BO if it was changed

Question 16

For vertical phoria what image should the patient be viewing?

Answer 16

Top image

Question 17

What instructions should be given to the patient for vertical VG?

Answer 17

Ask patient to look at top image
Ask them to let you know when the images line up side by side (like headlights on a car)

Question 18

How should prism be induced for vertical phoria testing?

Answer 18

Move the prism towards 0
2-3 pD per second
Bracket

Question 19

How is VG results recorded?

Answer 19

VG 4 exo,1 R Hyper

Question 20

What are normal results for VG?

Answer 20

Vertical (near and distance): Ortho/iso

Distance horizontal: 0-2 exo
Near horizontal: 2-6 exo