Used to measure Afferent Pupillary Defects (APD) which is defined as diminished pupil reaction to light levels. It uses 6 standard ND levels for quantifying APD. The log units quantify the amount of light transmitted through the filter. Includes 6 filters rated as 0.3, 0.6, 0.9, 1.2, 1.5, and 1.8 log unit optical density values. The 0.3 ND filter is most useful for uncovering a borderline pupil defect.

The filter bar can be used in conjunction with the “Swinging Flashlight” test to detect and quantify the depth of any afferent conduction defect.

#470550: Fits in shirt pockets. Includes leather slipcover. Overall bar is 6.5" x 1" (16.5cm long and 3 cm wide). Each filter measures 7/8" by 1" (2.5cm x 3 cm).

#151170: The filter sizes on the Large ND bar are 1.5 inch (38mm) square. Overall bar is 10" x 2" (25.4cm long x 5.0cm wide).