Prism Testing
(continued)
Vergence
Vergence Testing or Fusion Range Measurement - Distance
1. Press the
PRISM
button, or tap
Prism
.
2. Tap
Vergence
in the menu bar at the bottom of the screen. This test automatically advances through
the steps of measuring:
• Power of Divergence
• Power of Convergence
• Infravergence (Right Eye and Left Eye)
• Supravergence (Right Eye and Left Eye)
Note:
Tap
Skip
to omit a specific step in the Vergence test function. Tap it for each step in the test to
be skipped.
Power of Divergence
1. Set the acuity chart to a single vertical line of optotypes.
2. Enter BI prism slowly (starting from zero prism power), until the patient says the image is blurry.
3. Press the
CONTROL KNOB
, or tap
Blur
.
4. Enter additional BI prism, until the patient sees two images.
5. Press the
CONTROL KNOB
, or tap
Break
.
6. Enter BO prism until the images converge again.
7. Press the
CONTROL KNOB
, or tap
Recover
.
Note:
The amount of Prism at Blur/Break/Recovery appears in the designated boxes on the screen and is saved.
Power of Convergence
1. Set the acuity chart to a single vertical line of optotypes at or near the patient’s visual acuity.
2. Enter BO prism slowly in both eyes (starting from zero prism power), until the image is blurry to the
patient.
3. Press the
CONTROL KNOB
, or tap
Blur
.
4. Enter additional BO prism, if necessary, until the patient sees two images.
5. Press the
CONTROL KNOB
, or tap
Break
.
6. Enter BI prism until the images converge again.
7. Press the
CONTROL KNOB
, or tap
Recover
step in the test.
Performing an Exam
(continued)
61
16243-101 Rev. G
Summary of Contents for VISUTRON 900 Touch
Page 1: ...VISUTRON 900 Touch User s Guide ...
Page 85: ...Notes 85 16243 101 Rev G ...
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