Peds - Lecture 4

-Motor Fusion -Sensory Fusion

- Actual, physical alignment of eyes

- What the brain is doing to put 2 images together.

AKA: Simultaneous perception and superimposition. Characteristics: Targets may be completely different, no fusion lock and no similarities between 2 eyes

AKA: Flat Fusion Characterisitics: Flat, no depth, fusion locks, differences allow for fusion locks

AKA: Stereopsis Characteristics: Depth, ex. Random Dot

-Foveas pointing at the same object -The doubling of a nonfixated object -Physiologic supression usually prevents the observation of diplopia

Homonymous - when objects are beyond the point of fixation Heteronymous - when objects are in front of the point of bifixation

-Foveas at 2 different objects -Diplopia/doubling of a fixated object -Occurs in cases of strabismus w/o supression

-The appreciation of relative depth due to retinal disparity -"Barometer" of binocularity -If patient has BV problem they may have reduced stereo

Local and Global

-Line or contour stereo -Identical shape to each eye -Disparity created by displacing one image slightly

-No monocular shape to targets -Each eye sees a random dot pattern -The dots are displaced for one eye creating disparity -Generally requires bifoveal fixation -Microtypes may have local stereo but not global stereo

-Constant strabismics generally do NOT have stereo -Some small angle strabismics may have some stereo: - Local possibly as good as 60-70secs of arc -Global generally not perceived -Non Strabismic BV proteins -Generally normal or only mildly reduced angles -When stereo is worse than 50" loal and/or 250" global the clinician must try to determine why -Also, when local is worse than 20'-30', global should be checked as well

-"Real" Stereo Tests -Frisby -Polarized Tests -Randot book -Random Dot E -Random dot preschool -Lang 1&2 -Vectographic slide -Anaglyphic Tests -TNO