The I-Test Vision Screener is ideal for general screening (e.g. schools) and for highlighting refraction problems that may need professional attention. It has a power range (in each eye) of +/- 4.0 D in 0.50 D steps and is a Class 1 device under the EU directive. It utilises high quality optics with power tolarances of +/- 0.05 D and is sturdily designed. The I-Test Screener folds neatly away into its own box and can be patient or practitioner operated.