Measuring short-wavelength-sensitive cone discrimination thresholds using pseudoisochromatic figures displayed on a color monitor.
OBJECTIVE
To simplify the testing of short-wavelength-sensitive (SWS) cone function in the clinic.


METHODS
SWS-cone discrimination thresholds were measured along the tritan axis using pseudoisochromatic figures displayed on a color monitor. A circular 6 degrees field, containing spatially discrete patches of varying sizes and luminances, was presented on a background. A subset of patches formed the target patch in the shape of a C. Eight subjects with normal color vision reported the direction of the gap in the C using a cursor controlled by a joystick.


METHODS
were expressed in units of SWS-cone trolands.


RESULTS
SWS-cone discrimination threshold increased slowly as the SWS-cone trolands of the starting chromaticity increased. The dependence of the threshold on the SWS-cone activation level was similar to literature reports of chromatic discrimination measured with conventional paradigms.


CONCLUSIONS
The advantages of this method: (a) It is a simple intuitive task for patients. (b) The paradigm can be implemented with an 8-bit/gun color monitor. (c) The test avoids the need to define equiluminance for the individual patient before the color test is administered. This method can provide a useful technique for measuring SWS-cone function in a clinical population.
Watanabe
A
A
Visual Sciences Center, The University of Chicago, IL, USA.
Pokorny
J
J
Smith
V C
VC
D000328:Adult; D003118:Color Perception / Q000502:physiology*; D003119:Color Perception Tests / Q000379:methods*; D003117:Color Vision Defects / Q000175:diagnosis; D016288:Computer Terminals; D005556:Form Perception / Q000502:physiology; D006801:Humans; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*