Contrast sensitivity

Method

Contrast sensitivity function measured at named spatial frequencies, commonly 1.5, 3, 6 and 12 cycles per degree, by sine-wave grating test or by a contrast chart such as Pelli-Robson or CSV-1000, expressed as log contrast sensitivity. The spatial frequency, the test used, and the luminance and glare condition are recorded on the edge and are not optional.

The method is part of the endpoint identity. Studies measuring the same quantity by a different method are held as separate endpoints.

Notes

SIGN INVERSION HAZARD against logMAR visual acuity, obtained in the same session and also a log-scaled visual performance number: this improves by RISING and logMAR improves by FALLING. Beyond the sign, the several spatial frequencies are SEPARATE MEASUREMENTS, not repeats - high frequencies respond to optical clarity, low frequencies to neural and macular pigment effects, and they routinely move independently. An edge reporting this without naming the frequency is not comparable to any other edge on this node.