The relationship between the slow potential and spikes of second-order ocellar neurons of the cockroach, Periplaneta americana, was studied. The stimulus was a sinusoidally modulated light with various mean illuminances. A solitary spike was generated at the depolarizing phase of the modulation response. Analysis of the relationship between the amplitude/frequency of voltage modulation and the ...

PURPOSE We studied whether pupil size affects the flicker electroretinograms (ERGs) recorded by RETeval, a new mydriasis-free full-field flicker ERG system. METHODS We studied 10 healthy subjects. The RETeval manufacturer claims that the system delivers a constant flash retinal illuminance by adjusting the flash luminance to compensate for changes in the pupil size. Two experiments were perfo...

PURPOSE Using a scanning laser ophthalmoscope, it was found that some patients with relative central scotomas reliably used two different preferred retinal loci (PRLs) at different stimulus illuminances. This article describes adaptations in a patient's PRL for fixation when dimming the stimulus increased the relative scotoma size. METHODS Twenty-eight patients with macular diseases had their...

Stepwise increases in fluorescent illuminance, imposed as a single variable in a controlled environment, induced progressive stomatal opening in 8 plant species, as evidenced by a consistent decrease in leaf diffusion resistance (R(L)), ranging from 15 to 70 sec cm(-1) in darkness to about 1 sec cm(-1) at approximately 40 kilolux. The minimum R(L) values were the same for the upper and the lowe...

LEDs (light-emitting diodes) are superior to the conventional light bulbs and florescent lights in terms of low power dissipation, high efficient and longer lifetime. Therefore, conventional light bulbs are gradually being replaced by LED light bulbs as the next generation lighting source. LEDs are also playing more important roles in industrial applications, such as backlighting in LCD display...

Several investigators have related infants' low contrast sensitivity to immaturities in the optics and receptor lattice of the immature eye. A critical element in the modeling is how much the lower photon catch of the immature retina reduces sensitivity; the assumptions vary from square-root to Weber's law and lead to very different modeling outcomes. We measured the relationship between retina...

One of the most challenging applications for high brightness LEDs is in automotive headlights. Optical designs for a low or high beam headlights are plagued by the low flux and luminance of LEDs compared to HID or incandescent sources, by mechanical chip placement tolerances and by color and flux variations between different LEDs. Furthermore the creation of a sharp cutoff is very difficult wit...