Finely striated, clear lenses used for evaluating retinal correspondence in patients with eye deviations. Consists of 2 circular lenses, indexed and mounted in 38mm trial lens metal rings with tabs for use by the examiner. Used in the analysis of anomalous correspondence, suppression etc. In testing suppression, the lenses are placed in a trial frame with the striations at an angle of 135° and 45° for each eye respectively.
Then with a spotlight stimulus, such as a Penlights or transilluminator, a patient with no suppression will see two diagonal lines crossing above, below or at the light source. This can be accomplished at near or far distance. If suppression is present, all or part of one line will not be seen. If the diagonal lines cross at the source when the cover test indicated an ocular deviation, the patient has harmonious, abnormal retinal correspondence. Sold as a pair.