The CP-690 serves optometry practices and ophthalmology clinics that test distance vision at refraction distances of 2.9 to 6.1 m. It fits especially well in a room that holds more than one test position. Because each projector answers only the remote coded to it, up to eight units can run in the same space without one examiner changing another's chart.
Acuity work depends on the chart type fitted. Across the types, the acuity charts cover letters, Landolt rings, a Snellen scale, numbers and children's charts, and masks narrow any of them to a line, a column or one letter. The acuity keys step the mask up or down the scale, keeping the reading pace with the patient's answers.
Refinement and binocular checks sit in the same chart set. The red and green filter supports duochrome testing, the astigmatism detection chart supports cylinder checks, and binocular balance, phoria, coincidence, Schober and stereo charts cover the binocular stage, with the exact set varying by chart type. Polarised versions are viewed at 135° for the right eye and 45° for the left through the polarised glasses supplied. The Worth test uses red and green filters, and the fixation point chart uses a Maddox rod.
A practice can store a routine for most patients once in program A, B, or C on the remote, up to 20 steps each. Where the CP-690 is paired with the Nidek RT-2100 automatic refractor, the refractor's control box runs the projector, and a data connector ties it to the Nidek AOS series. Five luminance levels let the examiner set chart brightness for each room.