BV 3 - AC
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What is AC?
- when foveas of both eyes do not have a common visual direction
- fovea of one eye functions directionally with the extrafoveal point of the other eye
What is the objective angle?
What is the subjective angle?
What is the angle of anomaly?
How does a red lens test work?
- Red filter over deviating eye
- direct px to look at pentorch
- red light above/below or L/R of white light?
Adv of bagolini lenses?
more normal viewing conditions
Disadv of bagolini lenses?
- Need to know that there is a deviation present before performing the test as NAC and HAC can report the same results - lines cross through the light
- results may be contaminated by EF
- can only determine is normal/abnormal and not types of UAC
How to differentiate NAC and HAC with bagolini lenses?
- should know that there is a deviation beforehand
- otherwise maybe central suppression, or some of the lines may be suppressed
What will an LST and LXT with UHAC report with bagolini lenses?
- LST - cross below
- LXT - cross above
Hering Bielschowsky disad?
EF will affect test results
Hering Beilschowsky adv?
Can differentiate between NAC and AAC as well as types of UHAC
Hering Bielschowsky - objective cover test found 5PD LXT. Vert line flashed in OS and hoz line OD. Sees hoz line through the dot, vert line 2.5cm to the right of the dot, standing 50cm away. Has central fixation. What correspondence type?
Type 1 Unharmonious Anomalous Correspondence OS of 5PD
What is an advantage of the bifoveal cuppers test?
EF will not invalidate this test
What is a disad of the bifoveal cuppers test?
needs alot of px cooperation and understanding
Depth of AC?
- 1 test showing AC = shallow
- all tests showing AC = deep
What are the 4 factors that influence whether a test will reveal NC or AC?
- 1 degree of disassociation
- NC if eyes disassociated e.g. synoptophore and AI
- 2. Retinal area stimulation
- NC with bifoveal images e.g. AI
- 3. Eye used for fixation
- AC - dominant eye
- NC - non dominant eye
- 4. Variablility of deviation
- less estabilished AC if intermittent or variable angle
How is the prism adaptation test carried out?
- 1. Overcx with prism
- 2. Should still see deviation with CT (eg exo)
- 3. After 30-45m if see:
- a) still exo = negative PAT
- b) eso = add more prism so see exo on CT
- 4. After 30-45m- keep going until the px no longer adapts and not eso
- often occurs with AC + ST
- used to establish prognosis for surgical alignment
- final amount of prism = anomalous fusion response
- >20pd less success
Management of AC?
- difficult to train
- do not train out AC and leave deviation
- usually treated before suppression
- often isnt treated
Treatment options for AC?
- Synoptophore- flashing/moving
- over prescribing prism
- occlusion if constant strab
What would you like to do?
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