Keratometer BL-8002 can be used to measure the radius of cornea's curvature and dioptor.And it can also be to measure the axis and dioptor of cornea astigmatism. Specification Measurement Range Curvature Radius:5.5-12mm Dioptor:28-60D Minimum Division:Radius:0.01mm,Dioptor:0.125D Minimum Surface Required for Measurement: R=5.5mm φ1.65mm, R=7.5mm φ2.36mm, R=11mm φ3.36mm Light Source:LED Whole packing Volume:0.235m3 Carton Number:2 Total Weight:36kg