The red and green color lenses have been designed to produce the proper hue and tint. The lenses are 100% accurate in the cancellation of  Worth 4 Dot test, Three Character Test, most Lancaster Red-Green Tests, Hess Screen Test colors and training of fusion, suppression, and/or diplopia. Only the white circle can be seen until the light is turned on so that patients do not know how many circles are on the target in advance of testing.