Cover Test Flashcards
What is a tropia?
Manifest deviation
Visible
What is a phoria
Latent deviation and only visible in one particular gaze
If you cover one eye and see movement in the other eye that reveals…
…the presence of a tropia
Phorias are expressed in…
…both eyes
What is herrings wobble?
Cover eye and no movement when your introduce cover, but when you move away the other eye moves and then comes back
When doing alternating cover test a with movement means what and against movements means what
With - exophoria
Against - esophoria
What do you need to record when doing the cover test
Distance or near
With or without rx (c or s)
XOP,SOP, SOT, XOT hyper/hypo (RE/LE)
Magnitude: 20 prism diopters
Recovery movement (phorias only)
Prism bar cover test
Used to assess magnitude
Value of prism neutralises eye movement
Performed after cover test
Unilateral
The deviation (strabismus) is only ever present in one eye
Alternating
The deviation can exist in either eye. Only one eye deviates, but it can be the right eye or the left eye.
Constant
Deviation is present all the time
Intermittent
The deviation is present only some of the time
E.g. esotropia when the px is tired
Comitant vs incomitant
Comitant - the size of the strabismus does not vary with the angle of gaze
Incomitant - the size of the strabismus varies with the angle of gaze; the strabismus may only be present in one gaze direction or it may not be present in some gaze directions
