binocular video Flashcards
Motor fusion
The movement of the two eyes when retinal disparity is detected
Sensory fusion
Combinbin of two images in the visual cortex
What must happen for an object to be perceived as single
- Must fall on same retinal points 2. be clear 3. be similar size
Primary visual direction
The line of sight going through the foveal.
secondary visual direction
Lines of sight through all other retinal points.
Horopter
spatial representation of all points in space that are imaged on corresponding retinal points. Anything that falls on here will be seen as single
Panuo’s fusional space
an area immediately around the horopter where objects are still seen as single and in depth. This is where depth occurs
What VA to use with binocular vision testing
20/30 or two lines above there BCVA
Unilateral cover test
Allows the determination of a tropia vs. phoria.
ACT
Determines amount.
Expected phoria at distance
0-2 XP
Expected phoria at near
0-6 XP
Phi phenomeneon
With with XP. Against with EP.
what will you see with rod over L and hyper
Will see line below the light.
What will you see with rod over L and hypo
Will see line above the light
Exo on maddox rod
crossed
Eso on maddox rod
Uncrossed
Fixation disparity
small misalignment of the visual axes that is not observed as object falls in panuo’s fusional area. Measured under associated conditions.
Which AC/A will be greater?
The calculated due to proximal convergence.
What indirectly tests PRV
NRA
Which indirectly tests NRV
PRA
Blur point with fusional mergence testing
This is the limited of fusional mergence. Now they start using accommodative vergence
Break point
The limit of fusional and accommodative vergence
How big should the recovery be?
At least half the break.
What flipper to use with mergence facility
12 BO/3 BI.
What is normal mergence facility
15 CPM
How does the minus lens method differ from push up values
Minus lens will be 2 D less due to minifciation.
What values to test with accommodative facility
+/- 2.
Normal values for accommodative facility
8 cpm binocular or 11 cpm monocular
CI signs
large XP at near, low AC/A, receded NPC, reduced PFV, and a low lag, low NRP and trouble clearing plus lenses.
Pseudo CI
accommodative insufficiency leads to decreased convergence. Will have a decreased amplitude of accommodation, a low PRA, and will respond well to low plus at near.
What dx if patients presents will sudden symptoms of CI
MS and MG.
DI
Least common. Greater esophoria at distance, low AC/A, receded NFV at distance.
Convergence excess
Greater symptoms that CI. Reduced NFV ranges, higher AC/A and large lags. Will have a low PRA and inability to clear minus binocularity.
DE
Greater eco at distance than near. Can be more pronounced at near. High AC/A. PVF ranges at distance and near are usually normal? The patient may have a V pattern.
Basic XP
Normal Ac/A, reduced PFV, low NRA, low lag or lead, inability to fuse with Bo and clear plus
Basic EP
Normal AC/A, Reduced NRV, big lag, inability to fuse BI, hard to clear minus.
Vertical phobias.
Vertical phobias can be constricted if recent onset vertical deviation or larger than normal if the vertical deviation is longstanding.
Fusional Vergence Dysfunction
Normal phoria at distance and near, normal AC/A, normal accommodative function, and reduced PFV and NFV ranges at distance and near.
AI
high lag, inability to clear minus, reduced PRA, reduced amplitude of accommodation.