Amount of deviation were measured by alternate prism bar cover test, both for distance and near.
Any amount of overcorrection or undercorrection were measured by alternate prism bar cover test.
I use the horizontal prism bar most frequently to test the horizontal prism fusion range, but occasionally, I will use the vertical prism bar in order to check the vertical prism fusion ranges.
The test is repeated holding the prism bar in the opposite direction to measure the positive prism fusion range.
When using the prism bars, the patient is asked to report when a row of words or letters of an appropriate size first becomes blurred--N5 is generally used at near for patients with normal vision and accommodation--and they cannot see the text clearly after the lens is placed in front of it.
And it certainly wasn't by pretending they had just stepped into Superman's icebound Fortress of Solitude when standing at the Prism Bar
26) A prism from the trial set or a prism bar
is usually held in front of the patient's fixating eye.
Prism bar cover test--done for near and distance with appropriate refractive error correction appropriate prisms (Base--in/Base--out) The deviation was measured in all the directions of gaze.
12%) patients had no deviation on prism bar cover test.
On prism bar
cover test there was -55 PD of exodeviation and 4 PD of hypodeviation of the RE with marked amblyopia with central fixation.
Fusional ranges can be measured using a prism bar
or phoropter head.
These are measured using a prism bar
, and the fusional reserve opposing the phoria observed in the cover test should be measured first--for example base out to force convergence in exophoria.