cycle per degree

cycle per degree 

Unit of spatial frequency. It is equal to the number of cycles of a grating (one dark and one light band) that subtends an angle of one degree at the eye. Abbreviated: c/deg; cpd. This unit was developed because there is no finite width in a bar of a sine grating.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann