The cone-driven visual system is able to regulate its sensitivity effectively from twilight to bright sunlight. On the basis of a novel combination of short-wavelength-sensitive (S-) cone measurements of temporal sensitivity and temporal delay, we show that S-cone light adaptation is achieved not only by trading unwanted sensitivity for speed but also by an additional process that counterintuit...

We measured electroretinograms (ERGs) for the isolated short-wavelength-sensitive (SWS) cones using a substitution technique. The stimulus was a 5 Hz alternation of 460 nm and 565 nm or 490 nm and 565 nm light of equivalent photopic luminous efficiency. We used a 571 nm narrow-band adaptation field of 7000 td to improve SWS cone isolation and to suppress rod activity. The resulting SWS cone ERG...

Both long- and middle-wavelength sensitive cones mediate the reflex accommodation signal but the contribution from the short-wavelength sensitive cones is unknown. A short-wavelength sensitive cone contribution could extend the range of the signed defocus signal from chromatic aberration. The aim was to determine whether isolated short-wavelength sensitive cones mediate reflex accommodation ind...

The pioneering work of Stiles provided a means of psychophysically isolating and measuring the sensitivity of individual color vision mechanisms through the two-color increment threshold procedure. Basically, this approach involved decreasing the sensitivity of some color vision mechanisms (termed π mechanisms by Stiles) by using a chromatic adapting background light, and then measuring the sen...

PURPOSE To investigate variations in diabetic short-wavelength sensitivity with acute, induced changes in blood glucose level. METHODS Increment threshold measures were obtained for short-wavelength-sensitive and middle/long-wavelength-sensitive cone pathways after an induced, acute change in blood glucose level in diabetic observers. RESULTS Diabetic observers showed an increase in short-w...

This paper describes a technique that combines ideas of phase shifting interferometry (PSI) and two-wavelength interferometry (TWLI) to extend the phase measurement range of conventional single-wavelength PSI. To verify theoretical predictions, experiments have been performed using a solid-state linear detector array to measure 1-D surface heights. Problems associated with TWLPSI and the experi...

Using a light-emitting diode (LED) built-in contact lens electrode, we studied the effect of age on short-wavelength sensitive cone electroretinograms (S-cone ERG) and long- and middle-wavelength sensitive cone ERGs (LM-cone ERG). We recorded ERGs in 31 pseudophakic subjects to avoid the effect of yellowing in the human crystalline lens. The intensities of our stimuli were on the asymptote of t...

The determination of the relative numbers of different cone types in the human retina is fundamental to our understanding of visual sensitivity and color vision; yet direct measurement which provide this basic information have not previously been made for all cone types. Here we present a model which links the detection of a test light of small dimension to the number of cones contributing to d...