Midterm 1 Flashcards
(141 cards)
Define phoria
when both eyes are uncovered, both point toward the object of regard
What happens during cover test for a phoria?
when an eye is covered the eye moves out of alignment and when uncovered, alignment is quickly restored
What does a phoria tell us?
how the person is habitually calculating space
Define strabismus
when both eyes are open and uncovered, one eye is pointed at the target and the other is pointed somewhere else
What differentiates phoria with refixation from tropia?
tropia is when eye does not align after first blink (harris) or after 10 sec (bodack)
What is the old definition of amblyopia?
best compensated visual acuity is 20/40 or worse in either or both eyes
What is the newer definition of amblyopia?
best corrected visual acuity is 20/40 or worse in either or both eyes OR there is more than a 2 line difference between the two eyes
Why was the amblyopia definition updated?
to include some 20/25 to 20/30 best compensated eyes in the definition
What does Kraskin say about amblyopia?
amblyopia as a binocular dysfunction manifesting as amblyopia
How do the two channels often differ with amblyopia?
there may be specialization b/w the 2 channels: what and why activities
Which channel takes the lead for what activities?
the fellow eye
Which channel takes the lead for where activities?
the amblyopic eye
T/F it is irrelevant to talk of a good eye or bad eye
true, both channels have given something up in order to perform certain tasks better
What is the amblyopia prevalence in the military, school children, and patient’s seeking vision care?
1.6%, 1.8%, 2.3%
Define eccentric fixation
looking with the line of sight away from the fovea in an otherwise healthy eye
How will steady EF manifest with an ophthalmoscope?
the fovea will remain in the same or nearly the same relation to the axis of fixation
How will unsteady EF manifest with an ophthalmoscope?
the fovea will appear to move relative to the axis of fixation
What is the majority of fixation cases?
steady central
What is the hardest fixation to treat?
steady eccentric
Which fixation case has variable VAs?
unsteady central
What degrees do foveal center, foveal off-center, and parafoveal EF correspond to?
0, 0-1, and 1-3 degrees
What degrees do paramacular and peripheral EF correspond to?
3-5 and >5
What is the expected acuity for 1/2 degree off foveal center and 1 degree off?
20/25 and 20/30 respectively
What is the expected acuity for 2 degrees off foveal center and 3 degrees?
20/40-20/50 and 20/50-20/60 respectively