User's Manual

34 Specifications Welch Allyn Spot Vision Screener
DRA
F
T
Dimensions (in): 8½ x 6¾ x 4¾ (LxWxH)
Weight (lbs.): ~2.55
Wireless Network: 802.11 b/g/n
Operating Temperatures (°C): +10 to +40
Operating Humidity: 30% to 95% Relative Humidity (non-condensing)
Storage/Shipping Temperatures (°C): 0 to +50
Storage/Shipping Humidity: 0% to 95% Relative Humidity (non-condensing)
Storage/Shipping Atmospheric Pressure: 800 hPA to 1060 hPA
Expected Battery Life: 2.5 Years (Under Normal Usage)
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