Next ask the patient to cover the eye not being measured, look straight ahead and watch the blinking red light.
Keep the handle of the instrument vertical.
Slowly move the instrument until you see
four outer green lights, four inner green
lights and a central red blinking light in an
X configuration.
If the images are not properly aligned, the red and green lights will alternately blink until alignment is acheived. The instrument will not make the measurement until the lights are properly aligned.
See next screen to see how misaligned patterns appear.
