Paradoxical shifts in human color sensitivity caused by constructive and destructive interference between signals from the same cone class.

Paradoxical shifts in human color (spectral) sensitivity occur on deep-red (658 nm) background fields. As the radiance of the deep-red background is increased from low to moderate levels, the spectral sensitivity for detecting 15-Hz flicker shifts toward shorter wavelengths, although by more than is predicted by selective chromatic adaptation (e.g.

Long-wavelength adaptation reveals slow, spectrally opponent inputs to the human luminance pathway.

In addition to its expected fast, additive L- and M-cone inputs (L + M), the luminance pathway has slow, spectrally opponent inputs. We have previously shown that on long-wavelength fields, the dominant slow signals change from L-M at moderate intensity levels to M-L signals at high. Here, we focus on the transition between them, which we find is marked by substantial changes in temporal phase delay, and by large and unexpected shifts in flicker spectral sensitivity.

Spectrally opponent inputs to the human luminance pathway: slow +M and -L cone inputs revealed by intense long-wavelength adaptation.

The nature of the inputs to achromatic luminance flicker perception was explored psychophysically by measuring middle- (M-) and long-wavelength-sensitive (L-) cone modulation sensitivities, M- and L-cone phase delays, and spectral sensitivities as a function of temporal frequency. Under intense long-wavelength adaptation, the existence of multiple luminance inputs was revealed by substantial frequency-dependent changes in all three types of measure. Fast (f) and slow (s) M-cone input signals of the same polarity (+sM and +fM) sum at low frequencies, but then destructively interfere near 16 Hz because of the delay between them.

Spectrally opponent inputs to the human luminance pathway: slow +L and -M cone inputs revealed by low to moderate long-wavelength adaptation.

The luminance pathway has slow (s), spectrally opponent cone inputs in addition to the expected fast (f), non-opponent inputs. The nature of these inputs to luminance flicker perception was further explored psychophysically by measuring middle- (M-) and long-wavelength-sensitive (L-) cone modulation sensitivities, M- and L-cone phase delays, and flicker spectral sensitivities under three conditions of low to moderate long-wavelength adaptation. Under these conditions we find that the luminance channel has fast M- and L-cone input signals (+fM and +fL), and slow, spectrally opponent cone input signals (+sL and -sM).

Scanning laser entoptic perimetry for the detection of age-related macular degeneration.

Objective: To determine the sensitivity and specificity of scanning laser entoptic perimetry for detecting visual function damage due to age-related macular degeneration (ARMD).

Methods: We measured the presence or absence of visual field disturbances by entoptic perimetry and determined the severity of ARMD based on masked readings of fundus photographs. A prospective masked study comparing the findings of entoptic perimetry with fundus photographs was performed.

Paradoxical activity of CMV retinitis in patients receiving highly active antiretroviral therapy.

Purpose: To report two types of atypical behaviors of cytomegalovirus (CMV) retinitis in the highly active antiretroviral therapy (HAART) era, including active CMV retinitis in the presence of persistently high CD4 cell counts during HAART and CMV retinitis that has not reactivated despite persistently low CD4 cell counts.

Methods: Prospective, longitudinal, observational study of a cohort of 116 patients with acquired immunodeficiency syndrome who had a history of CMV retinitis during the HAART era.

Results: Sixty (52%) of the 116 patients with acquired immunodeficiency syndrome and CMV retinitis were HAART responders.