Fused Cross Cylinder Test; Nra/Pra Test - Ametek Reichert Phoroptor VRx User Manual

Performing an Exam
Near Vision Test

Fused Cross Cylinder Test

1. Select the Cross Grid Chart
Note: The Fixed Cross Cylinder lenses (+0.50 D, Axis 90°) are placed in the lens apertures.
2. Ask the patient: "Which is better (sharper and clearer), the horizontal or the vertical lines?"
3. If horizontal is better, turn the CONTROL KNOB to add plus (+) power, if vertical is better, turn the
CONTROL KNOB to take away plus (+) power.
4. Repeat steps 2 and 3, until the patient states that the horizontal and vertical lines appear equally
sharp and clear.
5. Press the CONTROL KNOB or the ENTER button, or tap Equal, to save the values.
6. To exit the test, perform one of the following steps:
A. Press the CONTROL KNOB or the ENTER button, or tap Set Add, to save the value to that
determined by the Fused Cross Cylinder test and exit the test.
B. Tap Save to save the values without setting the patient's Add value and exit the test.

NRA/PRA Test

Near Vision Addition can be determined by measuring Negative Relative Accommodation (NRA) and
Positive Relative Accommodation (PRA). The order of the test depends on the settings selected in the
Settings menu, either NRA/PRA or PRA/NRA.
1. Select a line of letters in descending size or other optotypes on the reading card.
2. Turn the CONTROL KNOB to add plus (+) power in 0.25 D increments, until the patient states that
the smallest lines of the optotype appear clear.
3. Continue to turn the CONTROL KNOB to add plus (+) power, until the patient states the image blurs.
4. Press the CONTROL KNOB or the ENTER button, or tap Blur, to save the upper limit.
5. Turn the CONTROL KNOB in the opposite direction to decrease plus (+) power, until the patient
states that the chart appears clear again.
6. Continue to turn the CONTROL KNOB to decrease plus (+) power, until the patient states that the
image blurs again.
7. Press the CONTROL KNOB or the ENTER button, or tap Blur, to save the lower limit.
8. To exit the test, perform one of the following steps:
A. Press the CONTROL KNOB or the ENTER button, or tap Set Add, to set the Add value to the
midpoint of the NRA and PRA values and exit the test.
B. Tap Save to save the NRA/PRA values without setting the patient's Add value and exit the test.
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on the reading card.
16241-101 Rev. E