Lecture 4 Flashcards
When should convergence talk place in a child
Ages 1-3 months
1 month: can be done
2 month: Consistent
3 month: without delay
How to test NPC on kids?
Same way as adult, but use interesting target.
cm, lateral canthus, OU open.
Usually would ask adults to tell you when it breaks, but do not do this with kids. Watch their eye and see if it swings out.
Normal NPC values
Normal: 5cm/7cm. Lower vales are good (were able to get closer to patient before double. Ex: TTN). Lower values are bad. Mean you were further away from pt when they doubled. May need VT or prism.
Subjective phoria test
Subjective measurement of binocularity using Von Grafe. Cannot differentiate from a phoria vs intermittent trope behind phoropter.
12BI OD, 6 BU OS
Headlights on a car for vertical.
Buttons on a shirt for horizontal.
Show kids with hands fist and have them tell you when to stop once hands are aligned.
Verenge testing purpose
To test fusional vergence amplitude with prisms.
Vergence works with accommodation system always. Shows quality of binocular function.
Done at distance and near- we are doing a lot more near work now a days.
3 values:
Blur, break, recovery
Can do this in the phoropter (smooth with risley bar) and using a prism bar (step vergences)
Prism bar vergences/step vergences
- Purpose
- how to do it
- Normal values at near
Can observe objective eye movements, can also ask pt when target gets double and then becomes single again.
Normal:
Near base in: X/12/7
Near base out: X/23/16
Smooth vergence in phoropter with risley prism. Morgan’s norms at distance and near
Distance BI: x/7/4
Distance BO: 9/19/10
Near BI: 13/21/13
Near BO: 17/21/11
Worth’s degrees of fusion
1st: Simultaneous perception. Fusable, but no common features. Lion and cage. Both eyes are working, images may not be fused.
2nd: Flat fusion. Both bunnies with similar features + some different. 1 has flower, 1 has tail. Both eyes working, single image formed. No depth.
3rd: Stereo. Depth.
When does stereo emerge
at 3-4 months. By 6 months, almost 100% of infants appreciate stereo
Not demonstrable under 8 weeks.
Ex: Visual Cliff experience
Bernell Functional Binocular Assessment Test
Bernell Functional Binocular Assessment Test (previously the keystone) Good for young, non verbal patients.
Not random.
Pt wears red/green glasses at 20-30 cm. See if child reaches for the target. If they touch the page, they don’t see it.
Examples of stereo testing with infants
Bernell Functional Binocular Assessment Test
- Good for non verbal children or adults
- Red/green glasses. Child will reach out to grab image.
Smile
- Polarized glasses.
- Preferential looking test. Does child look at smile?
Lang
- No glasses worn
- Ask child to point/look at/name figure they see
Random Dot E
- Polarized glasses
- Toddler/preschoolers: have 3 cards. Preferential looking
- Preschool/school aged: Global matching (shapes) and local with ran dot background (Wirt circles, animals) stereo.
Tutmus fly/butterfly
-More gross
Smile Stereo testing
Preschool aged children.
Polarized glasses.
Preferential looking test. Does child look at smile?
Lang stereo testing
Does not require polarized glasses. Ask child to point to or look at figure. Pt can name if they see it.
Random Dot E for toddlers/preschoolers
Polarized glasses
Preferential looking- have 3 cards. Raised E, stereo E, and blank card.
Random Dot E for preschoolers/school aged
Polarized glasses Global stereo (shapes) matching. "See this circle on the front of the book? Can you find the circle inside?"
Local stereo (Wirt circles and animals) with random dot background.