Measurement of the spectral and spatial responses of the human eye\u27s blue sensitive system and the effects of lateral inhibition by the red and green sensitive systems

A study was conducted to measure the change in spatial modulation sensitivity of the human eye\u27s blue sensitive system at low light levels due to color shift, intensity change, and accommodation of red and green sensitive systems with yellow light. A testing device was designed which allowed a wide range of variation in viewing conditions for targets of several spatial frequencies. IV Results indicate that the ability to resolve gratings by the blue cones is depressed by lowering grating intensities but does not depend on wavelength within the blue cone sensitivity envelope to any extent greater than that explained by simple spectral sensitivity. Applying a uniform yellow illumination over the gratings, exciting red & green cone systems, depresses the ability to detect gratings consistent with Weber\u27s law. This implies no lateral inhibition between the blue cones and the red or green cones at low intensities