Occluders are cupped to a 70mm radius. This occluder is 25cm long and has a frosted lens AND a standard (opaque) occluder cup.
This new occluder uses a lightly frosted, scratch resistant lens that degrades the acuity of the non-tested eye while not inducing suppression effects. The reading eye is thus tested with an absolute minimum of interference from the other eye.
Plastic is durable and easily cleaned.