Linear isolating masks are used when an eye chart is installed in an illuminated cabinet. The patient holds the mask horizontally in front of the chart to isolate an individual symbol or letter.

The mask with the 1" x 1" square hole is used to isolate smaller objects 20/50 etc. The mask with the 1.25" x 1.25" square hole is used to isolate larger objects 20/100 etc. The mask with the 1" x 4.5" slot is used to isolate (complete this description).

Each mask is 14" x 6" and can be used with the ESV1200™, ESV1500™, Model A+, or Model A illuminated cabinets.