Bagolini lenses vs. PFL filters in the diagnosis of correspondence

This study introduces a new product, the PFL-7501 filter (prism linear filter), as a test for correspondence. Thirty consecutive strabismic subjects were asked to verbally describe, then draw, the images seen from a small light source through the Bagolini #4 striated lenses and the PFL-7501 filters. A 97% concordance was found between the two materials. The bright, multicolored streaks seen through the PFL filters were easier for all subjects to see and describe than the images seen through the Bagolini striated lenses.