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3.3 Viewed from the Measuring Window
Fig.4
C1. Measuring Window Glass
Testee sees through it to the green target.
C2. Calibration Reference Mark
It is used to check measurement accuracy.
C3. Benchmark Hairspring
When the optometrists use the device, they can slide the key and
make the benchmark hairspring level at the reflecting light spot of
the testee's pupils.
C4. Guide Mark
Guide Mark is used to target at the top of cornea of the testee during
the process of VD measurement.
3.4 Viewed from the Observation Window
Target to be stared at in the center of the device's inner visual field,
an eyeball-shaped circle can be seen. It is a green target image
surrounded with a bright ring. A testee should stare at the target with
both eyes when measuring. To adapt to the favor of people's eyes, the
device sets the adjustable function of LED brightness.