Perimetry is the topographic and quantitative study of sensibility in the visual field. The generally used classification of perimetry as so-called qualitative and quantitative perimetry is not fully definitive or accurate. The distinction between these two classes of perimetry lies entirely in the use of chromatic stimuli in the former and achromatic stimuli in the latter. Both are fundamentally quantitative in this sense, for in order to make a study of the field the stimulus in either case must be varied in quantitative value, by varying its brightness or by varying its size.
In place of this somewhat misleading nomenclature, I prefer to consider study of the visual field under the two fundamental divisions: (1) topographic and (2) quantitative. Topographic perimetry refers to the study of the variation of sensibility throughout the field, while quantitative perimetry refers only to the study of the existing sensibility in relation to normal sensibility
BAIR HL. SOME FUNDAMENTAL PHYSIOLOGIC PRINCIPLES IN STUDY OF THE VISUAL FIELD. Arch Ophthalmol. 1940;24(1):10–20. doi:10.1001/archopht.1940.00870010032003