11. Prisms Flashcards
What is Prentice prism position?
Light enters at 90 degrees
Flat part of the prism sits parallel to the eye
All deviation occurs at the exit surface
What is the spatial volume effect of BD prisms?
Shifts spatial volume up and out
Increases visual spatial volume
What is the effect of BU prisms?
Shifts spatial volume down and in
Decreases visual spatial volume
What effect does BI prism have on visual space?
Displaces visual outward
Increases visual space
What does BI prism do to the muscle tone of the neck and upper back?
Reduces it
Which prism enhances figure?
BO
Which prism enhances ground?
BI
What is the spatial effect of BO prism?
Displaces visual outward
Decreases visual space
What does BO prism do the the muscle tone of the neck and upper back?
Increases it
What are the volume changes of a prism in relation to the apex and base?
Expansion = apex Contraction = base
Prisms affect which 4 systems?
Visual
Kinesthetic
Vestibular
Proprioceptive
What prism do you give for an anterior midline shift?
Base down (opens things up)
What prism do you give for a posterior midline shift?
Base up
What prism do you give for a left midline shift?
Base right
What prism do you give for a right midline shift?
Base left
