BV-phorias and vergences
Terms
undefined, object
copy deck
- In an exophoric eye, light will fall on the _____ part of the retina but appears on the _____ part of the patient's visual field
- temporal, nasal
-
-____ are monocular eye movements
-Both eyes moving in the same direction are called ___
-Both eyes moving in opposite directions are called _____ - ductions, versions, vergences
- The near triad consists of
- Accomodation, convergence, and miosis
- Increasing accomodation will ALWAYS cause an increase in
- convergence and miosis
- minus lenses ______ accomodation and plus lenses _____ accomodation
- stimulate, relax
- minus lenses ____ an exophore and ____ an esophore where as plus lenses do the opposite
- reduce, increase
- What is the purpose of Von Graefe phoria?
- To measure subjectively the relative horizontal or vertical deviation of the eyes, one with respect to the other when fusion is interrupted using prisms
- What are the prism specifications for Von Graefe phorias?
- 6^BD OD, 12^BI OS
- When testing lateral phorias the patient should focus on the ______ target
- upper
- When testing vertical phorias the patient should focus on the _____ target
- lower
- What should you always ask the patient before beginning to test phorias?
- Do you see 2 targets one up and one down?
-
-If patient is ortho the should see____
-If patient is 12 XP should see _____
-If patient is EP than should see______
-if patient is >12XP than will see _____ -
-one up and one down to the left
-one right on top of the other
-more eso is created
-one up and one down and to the right - What are the instructions given when testing lateral phorias?
- focus on the upper target and let me know when the other lines up like buttons on a shirt
- Should the line of letters be vertical or horizontal when testing lateral phorias
- vertical
- What is the next step in measuring lateral phorias after verifying the patient sees two targets?
- Decrease the BI prism until the two lines are vertically aligned
- What do you record for lateral phorias?
- magnitude and direction of the phoria
-
If BI than the patient is ___
If BO than the patient is ___ -
Exophoric
Esophoric - What is the difference in Von Graefe phorias and the Flash technique?
- When using the flash technique you occlude the eye with the measuring prism (OS)...remove the occluder briefly giving the patient the same instructions as before
- What is the benefit of doing the Flash technique?
- the patient has no opportunity to make fusional movements
- What is the target for measuring vertical phorias?
- a horizontal line of letters one line above BVA
- What are the instructions for measuring vertical phorias once you verify the patient can see two lines?
- Focus on the lower target and let me know when the upper target lines up like headlights on a car
- Which prism do you change when measuring vertical phorias?
- The BD prism
- What do you record for vertical phorias?
-
magnitude and the hyper eye
EX: 1 R Hyper - What are the similarities between measuring lateral and vertical phorias at distance?
- Place the distance PD and the manifest in the phoropter in dim light
- What are the similarities between measuring lateral and vertical phorias at near?
- Place the near PD and the near correction in the phoropter in bright light with stand lamp
- What is a difference between measuring near and distance phorias?
- When measuring near phorias the patient could compensate the 12 BI before the test begins
- If the patient can compensate for 12^BI than what is the next step?
- Either increase the BI or make it 12^BO
- What are some things that can be done if the patient only sees one image?
-
-check that both lens wells are open
-change magnitude of the prism
-recheck PD - What are some advantages to measuring phorias with Von Graefe?
-
-fine control of prism magnitude
-relatively quick
-in phoropter makes it easier for the patient
-can easily determine the gradient AC/A - What are some of the disadvantages of Von Graefe phorias?
-
-less info than the cover test
-peripheral fusion is restricted due to phoropter
-limited to primary gaze
-depends on patient response b/c it is subjective