Distance Phoria* Flashcards
What is the purpose of subjective phoria testing?
Assess patient’s natural horizontal and vertical eye posture at distance and near
What is the illumination for VG?
Dim for distance
Bright for near
Is the patient corrected during this test?
Yes, proper distance and near refraction
What is the target for VG?
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
Is distance or near phoria testing performed first?
Distance
For the first step of VG what prisms should be placed in front of each eye?
12 BI OD (top image)
6 BU OS (bottom image)
What should you ask the patient after placing the prisms?
How many images do you see?
What should you do if the patient does not see 2 images?
Place 12 BO OD and ask again
After ensuring that the patient sees two images, what should you ask?
Is the top image to the right or the left of the bottom?
What should you do if the top image is to the right?
Patient is uncrossed (eso)
Prism should be moved in the direction of BO
What should you do if the top image is to the left?
Crossed disparity, expo
Prism should be moved to BI
What should you instruct patient as you move the prism wheel?
Let you know when the two images are on top of each other (buttons on a shirt)
Keep focus on bottom stationary image
At what rate should the prisms be moved?
2-3 prism D per second
How do you bracket?
Move 2-4pD past location where they match up and move back down
Average the results
What should be done after finding the phoria for OD?
Reset to 12 BI or 12 BO if it was changed
