Performing Measurements; Environmental Considerations; Figure 6: Measuring Environment - PLUSOPTIX A12C User Manual

3 Performing Measurements

Mobile Pediatric Autorefractors "plusoptiX A12C", "plusoptiX A12R" respectively, measures
both eyes simultaneously (binocular) in 0.5 seconds at a distance of one meter (3.3 feet).
Therefore even small children with a short attention span can be measured starting at the age
six months. The simultaneous measurement of both eyes also enables a reliable comparison
of the measurement values of both eyes.
3.1

Environmental considerations

The device uses infrared light to perform measurements. The same infrared light is part of
sunlight and emitted by all incandescent light sources such as light bulbs and halogen spots.
This infrared light is invisible to the human eye and nonhazardous. To obtain accurate
measurements it is important to avoid interfering infrared ambient light in the examination
room. Curtains, blinds or shutters should be closed to exclude sunlight. Switch off all heat-
emitting light sources. However, examination room does not need to be dark. Cold light
sources such as energy saving lamps or neon tubes do not affect measurement results.
No direct sunlight
See chapter 3.5
1 meter measuring
distance
At eye level
See chapter 4.2
Pupil diameter
Minimum 4 mm
Maximum 8 mm

Figure 6: Measuring environment

To be able to perform a measurement, the child must look at the device. Ensure that the child
is sitting straight and does turn his head across the shoulder. The child's knees and nose must
point towards the camera.
The attentiveness of small children is attracted by playing a special "warble" sound on the
device. However, this works only if the child is not distracted by other persons or objects in the
examination room. Ensure that you close the door to the examination room and avoid activities
that divert the child's attention such as walking around or snapping your fingers. Do not use
additional fixation aids!
The attention span of small children is extremely short. Take advantage of the fact that the
examination room is new to the child. An unusual "warble" sound in this unfamiliar
environment always evokes interest. Enter the patient data into the device before calling the
child into the examination room or after completing the measurement. Avoid protracted
information exchange with parents before the measurement.
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