Principle
The manual refractometer is composed of a lens and a removable eye chart. The testee is required to move the position of the eye chart after resetting to make the visual target become clearer from blur. Once the clearest position of the visual target is determined, the testee’s estimated refractive error can be read from the display screen of the instrument.
Specifications
Sphere range：-12D~+6D (step 0.25D)
Battery duration：8 hours
Battery voltage：D.C.4.5V
Operating Environment Conditions：Ambient temperature range: 5 ~ 40°C
Relative humidity: ≤ 80%
Atmospheric pressure: 86kPa ~ 106kPa
Transport and storage environment：Ambient temperature range: -20°C ~ 55°C
Relative humidity: ≤ 93%
Atmospheric pressure: 86kPa ~ 106kPa
Dimensions (mm)：185 x 47 x 55
Net Weight (g) 195：(batteries not included)
Feature:
Estimate refractive error
Evaluate astigmatism
Estimate far and near vision
