Assessment of Nonstrabismic Binocular Disorders (M1) Flashcards
Does an underaccommodation cause an increase or decrease in exophoria?
increased
What are the expected phoria measurements at distance and near for presbyopes?
- 1pd eso distance
2. 8pd exo near
What is the lack or inability of perception of normally visible objects in all or part of the field of vision of one eye, occurring only on simultaneous stimulation of both eyes and attributed to cortical inhibition?
suppression
Is binocular accom facility a direct or indirect measure of binocular vision?
indirect
While using the Wesson or Borish card, if the line seen by OD (usually upper) is on the right and line seen by OS is on the left, what is the disparity (crossed or uncrossed)?
eso disparity (uncrossed)
While using the Wesson or Borish card, if the line seen by OD (usually upper) is on the left and line seen by OS is on the right, what is the disparity (crossed or uncrossed)?
exo disparity (crossed)
What is vergence facility measured with? 1. What is the procedure? 2. What is the norm? 3
- 12 BO and 3 BI split prism
- number of cycles in 1 minute (near only)
- 10 cpm
What distance is teh Wesson card held at?
- 25cm for pre presbyopes
2. 40cm presbyopes
What is the normal range of Randot stereo for people age 3? 1. Age 4 to 5? 2. Age 6? 3. Age 7 to 17? 4
- 40” to 400”
- 40” to 200”
- 40” to 100”
- 40” to 60”
What is the expected value of PRA (with std dev)? 1. What does this do to accom? 2. What vergence aspect does it measure? 3
- -2.37 (+/-1.00)
- exertion
- negative fusional range
What is the expected Stereosmile 2 score for ages 3 to 5yo?
120” or better
What are good tests for suppression?
- orthoscope
2. worth 4 dot flashlight
Is acommodative response a direct or indirect measure of binocular vision?
indirect
When considering the AC/A what needs to be considered?
- effect of proximal accommodation
- effect of lag of accommodation
- clinical usefulness for prescribing lens additions
What is an irregular fixation disparity curve due to?
accommodative inaccuracy and resultant convergence dysfunction
What are examples of random dot (global) stereo?
- random got E
- random dot E target on BVAT or Borish card
- randot preschool
- randot stereosmile
- Lang
How long does a phoria take to stabilize?
around 20sec
What is the distance that the distance Modified Thorington card is done? 1. Near card? 2
- 10 feet
2. 16 inches
What is the duration of a cover stroke during unilateral cover test?
2 to 3 sec
Is the fusional facility or vergence dynamics a direct or indirect measure of sustaining ability? 1. What is it especially useful for? 2
- indirect measure
2. unclear etiology of symptoms
What is the forced vergence fixation disparity testing especially useful for?
- unclear etiology of symptoms - related to symptoms
2. steep slope, large associated phoria and/or significant fixation disparity associated with symptoms
What is the expected value of NRA (with std dev)? 1. What does this do to accom? 2. What vergence aspect does it measure? 3
- +2.00 (+/-0.50)
- relaxation
- positive fusional range
What is the size (in degrees) of a foveal suppression? 1. Central suppression? 2. Peripheral? 3
- less than or equal to 1deg
- more than 1deg and less than or equal to 5deg
- greater than 5deg
What are examples of contour (linear) stereo?
- stereofly
- randot circles
- BVAT circles
- Borish card circles
Is NRA and PRA a direct or indirect measure of of binocularity?
indirect
What is the technique to test cyclodeviation? 1. Does an inward rotation of the top Maddox rod show an incyclo or excyclodeviation? 2 Outward rotation? 3
- double Maddox rod test (BIO and fundo photo used objectively)
- incyclo
- excyclo
What is it called when images of a binocularly fixed object are not imaged precisely on corresponding retinal points, but are still within Panum’s fusional area? 1. What is the usual amount in arcmin and pd? 2
- fixation disparity
2. 6’ or less than 0.25pd
What are the expected break values of NPC with a penlight target (with deviations)? 1. Recovery? 2
- 3cm +/- 4cm
2. 5cm +/- 5cm
What is the fixation disparity a measurement of?
associated phoria
What are the expected break values of NPC with an accommodative target (with deviations)? 1. Recovery? 2
- 2.5cm +/- 2.5cm
2. 4.5cm +/- 3cm
At what distance is the penlight held when testing versions?
30cm
What are the ways to directly measure fusion ranges?
- BI/BO bar vergences
2. BI/BO von Graefe vergences
What is the best procedure to find the gradient AC/A ratio?
- CT
- phoria with BVA
- phoria with BVA +1.00
- phoria with BVA -1.00
- average of two lens phorias
What is the disadvantages to von Graefe technique?
- repeatability
- variability
- increased time
What are the ways to measure fixation disparity?
- disparometer
- Borsih card (near)
- Wesson card
- Nearpoint Anaglyphic vertical associated phoria card
What are the ways to measure an associated phoria?
- Borish card (near)
- Wesson card
- vectograph slide
- Canela VA system
- AO vectogrphic slide (dist and near)
- “disparity” on Canela or Miramed VA systems
What is the definition of comitancy in relation to phoria measurement?
5 or more pd in change of phoria from gaze or fixating eye
What are the expected phoria measurements at distance and near for young adults and children?
- 1pd exo distance
2. 3pd exo near
What are the expected BI distance vergences for von Graefe? 1. BI near? 2. BO distance? 3. BO near? 4
- x,7,4
- 13,21,13
- 9,19,10
- 17,21,11
What are the techniques to assess a patients phoria?
- cover test
- Modified Thorington
- von Graefe phoria test
- Maddox rod