Measurements – Welch Allyn VS100 Welch Allyn Vision Screener - User Manual User Manual
Page 30
P/N 20146 Rev A
Page 30
Measurements
Refraction
Spherical Equivalent:
• Range:
-7.50D to +7.50D in 0.25D increments
• Accuracy:
-3.50D to 3.50D,
±
0.50D
-7.50D to < -3.50D,
±
1.00D
> 3.50D to 6.00D,
±
1.00D
Cylindrical:
• Range:
0.00D to +3.00D in 0.25D increments
• Accuracy:
0.00D to 1.50D,
±
0.50D
> 1.50D to 3.00D,
±
1.00D
Cylindrical Axis:
• Range:
1 to 180 degrees in 1-degree increments
• Accuracy:
± 5 degrees (for cylinder values > 0.5D)
Pupil size:
• Range:
4.0 mm to 9.0 mm in 0.1 mm increments
• Accuracy:
± 0.1mm
Pupil distance:
• Range:
35mm to 80 mm in 1 mm increments
• Accuracy:
± 1 mm
Time per measurement: 1 s
Measuring distance:
1 m ± 5 cm
Fixation target:
Random visual pattern and audible sound
Measurement principal: Optical reflex