Binocular Balance With Prisms - Ametek Reichert Phoroptor VRx User Manual

Instructions for Use
Prism Testing
(continued)

Binocular Balance with Prisms

Use binocular balance with prism to determine if the monocular VAs are the same. (Please refer to
Figures IU-38 & IU-39.)
1. Press the BB button, or touch BB on the main screen, to begin the Binocular Balance prism test.
2. Set the acuity chart to a single horizontal line of optotypes at slightly better than best visual
acuity for the patient, or a single optotype. The Binocular Balance test automatically places
prism in each eye (3Dio. BD in the right eye and 3Dio. BU in the left eye).
3. Verify that the patient can see two images, one up and one down.
A. Touch PRISM to adjust the Prism values if the patient cannot see two images.
B. Touch SET PRISMS to save the modified Prism values.
Note: The sphere values automatically fog by the amount specified in the Settings Menu.
4. Ask the patient: "Which image is clearer, the top or the bottom?"
• If the top image is clearer, adjust sphere in the right eye.
• If the bottom image is clearer, adjust sphere in the left eye.
5. Add +0.25 D to the eye that sees a clearer image, until both lines look equal.
6. Press the CONTROL KNOB, or touch EQUAL.
7. Decrease sphere in both eyes to reach the best visual acuity.
8. Press the CONTROL KNOB, or touch SAVE.
Figure IU-38, Binocular Balance with Prisms
16241-101 Rev. D
(continued)
Figure IU-39, Binocular Balance with Prisms
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