Distance Vergence Ranges* Flashcards
What is the purpose of testing vergence ranges?
To assess a patient’s ability to converge/diverge/elevate/depress their eyes while provided with a constant accommodative stimulus. The goal is to elicit diplopia
What is the illumination for vergence ranges?
Dim for distance, bright for near
Is the patient corrected during this procedure?
Yes proper distance refraction in phoropter, or near Rx
What is the target for vergence ranges?
Distance: single letter 1-2 lines above BCVA
Near: vertical (for BI/BO) or horizontal (for supra/infra) line of letters on near card at 40cm
What prisms should be placed in front of eyes for horizontal distance vergence??
BI and BO at 0pD
Which direction compensating range should be tested first?
Horizontal
If horizontal was normal was direction should be performed first?
BI
What should be asked of the patient before starting vergence ranges?
Is the target clear and single?
What direction should we move the prisms first, depending on phoria results?
Use compensating range
The compensating range is the range
that opposes the phoria (BI for eso, BO for exo). If the patient’s phoria is normal, perform BI first.
When should each number be recorded as prisms are changed for the patient?
When target becomes blurry or double
Bracket
Recovery
If I started with compensating range BO, do I have to perform BI?
Yes
Where should prisms be placed for vertical vergence ranges?
Set to 0pD in the vertical directs (BU and BD)
For vertical vergence ranges do we test one eye at a time?
Yes
How do we test for R and L Infra (one eye at a time)?
Slowly move prism up monocularly (base up) until patient reports diplopia (no blur)
Move 2-3 past then move back and ask when target becomes one again
How do we test for R and L Supra (one eye at a time)?
Move prism down monocularly (base down)
