1. We have studied the sensitivity of macaque retinal ganglion cells to sinusoidal flicker. Contrast thresholds were compared for stimuli which alternated only in luminance ('luminance flicker') or chromaticity ('chromatic flicker'), or which modulated only the middle- or long-wavelength-sensitive cones ('silent substitution'). 2. For luminance flicker, the lowest thresholds were those of phasi...

PURPOSE In the retina there is general agreement that blood flow adapts in response to different conditions of light and darkness including diffuse luminance flicker. By contrast, regulation of choroidal blood flow in response to different light conditions is still a matter of controversy. Thus, we investigated the effect of diffuse luminance flicker on choroidal and optic nerve head blood flow...

Flicker modulation sensitivity measurements made on high intensity orange steady backgrounds indicate that signals from short-wavelength sensitive cones (S-cones) have access to two pathways. At low S-cone adaptation levels the frequency response falls quickly with increasing frequency, but at higher adaptation levels it extends to much higher frequencies. At these higher S-cone adaptation leve...

This paper proposes a method to estimate the flicker severity index using the Hadamard transform. A weighting filter in the sequency domain is utilized for direct computation of the flicker index. The proposed method is compared with a flicker meter in the frequency domain that uses the Fast Fourier Transform (FFT). It is seen by numerical simulations that the proposed method yields flicker sev...

Dark adaptation and the rise of cone flicker threshold (25 Hz) during dark adaptation were measured psychophysically in three patients with fundus flavimaculatus. The dark adaptation curve showed a delayed rod-cone break but a normal final rod threshold in all these patients. However, the rise of cone flicker threshold during dark adaptation was not delayed and also reached a normal final value...

We have studied psychophysically the characteristics of the postreceptoral stage of visual processing, using heterochromatic brightness matching (HBM) between 540 and 600 nm, and hue discrimination between 565 and 585 nm, under differing luminance flicker (0-30 Hz) and excitation purity (1.0-0.1) conditions. The HBM curves exhibit deeper minima around 575 nm with decreasing purity. The minimum ...

In phototropic tests with young Limulus, the phototropic reactions to flickering fields were studied. If the two fields are equal in area and brightness but different in flicker frequency, the number of animals going to the two fields is proportional to their flicker frequencies. Equal stimulating effects of two fields differing in flicker frequency are obtained by reduction of the area of the ...

Background: Gold standard penalization therapies for amblyopia are thankfully being challenged by new techniques and new technologies. One such technology, rapid alternate occlusion or alternating flicker was recently studied and improved visual acuity and stereopsis in anisometropic amblyopes. Methods: Starting with a recapitulation of the Eyetronix Flicker Glass Clinical Study of the affect o...

We measured human psychophysical detection thresholds for test pulses which are superimposed on spatially homogeneous backgrounds that have abrupt onsets and offsets of high-contrast 25 Hz flicker. After the onset of the background flicker, test thresholds reach their steady-state levels within 20-60 ms. After the offset of the background flicker, test thresholds remain elevated above their ste...