Orthoptics I - Orthoptic Measures

What is the typical distance PFR?

15BO - 5/7BI

What is the typical near PFR?

35/40BO - 15BI

What is the typical vertical PFR?

3BU - BD

What is the typical cyclo PFR?

3excylco - 3incyclo

What does controlled binocular acuity assess?

control under accommodative stress

What does controlled binocular acuity indicate?

intermittent deviations that are influenced by accommodation, such as accommodative esotropia and intermittent exotropia

What may influence the choice of stereopsis assessment?

motor control
- any glasses may be too dissociative

Why do we need to measure deviations?

- for an accurate diagnosis
- allows interpretation of motor fusion assessment (is there sufficient motor fusion to compensate the deviation)
- assess for stability/deterioration
- information for treatment planning

Give some examples of ways to measure deviations?

- Hirschbergs test - corneal reflections (manifest)
- Prism Reflection Test - quantifying corneal reflections
- Prism Cover Test - maximum size of phoria/tropia
- Simultaneous Prism Covert Test - manifest
- Synoptophore

Describe Hirschbergs Test

relies on corneal reflections
- manifest deviations only
- use a non-accommodative target
- near measurement only
- non dissociative, so total deviation is not measured

1mm of displacement = 5-7degs

Describe the Prism Reflection Test/Krimsky Test

relies on corneal reflections
- prism induced over fixing eye
- increase the prism until corneal reflections are symmetrical

Describe the Prism Cover Test

alternate or simultaneous
method of choice
- use an accommodative target