OBJECTIVE To study the effect of cataract on electroretinographic responses. MATERIAL AND METHOD Thirty subjects with dense cataracts underwent electroretinogram (ERG) recordings before and after cataract surgery, using RETIport32 (Roland Instruments, Germany). The degree of cataract was classified according to the Lens Opacities Classification System III (LOCS III). No significant eye diseas...

Rods and cones subserve mouse vision over a 100 million-fold range of light intensity (-6 to 2 log cd m(-2)). Rod pathways tune vision to the temporal frequency of stimuli (peak, 0.75 Hz) and cone pathways to their speed (peak, approximately 12 degrees/s). Both pathways tune vision to the spatial components of stimuli (0.064-0.128 cycles/degree). The specific photoreceptor contributions were de...

A certain percentage of patients complain of "glare" at night after undergoing a refractive surgical procedure. When patients speak of glare they are, technically, describing a decrease in quality of vision secondary to glare disability, decreased contrast sensitivity, and image degradations, or more succinctly, "night vision disturbances." The definitions, differences, and methods of measureme...

Purposes: a) comparison of two presbyopia correction methods – with multifocal and monovision contact lenses – by means of precise contrast sensitivity measuring under scotopic, mesopic and photopic conditions simultaneously; b) new computerized AltTechNV Thru‐luminance CSF test trial operation. Methods: contrast sensitivity of 14 initial presbyopes (40÷51 y.o., never wore contact lenses, use...

Contrast gain reflects the rapidity of response amplitude increase with increase in stimulus contrast. In physiology, contrast gain can be measured directly as the initial slope of cell contrast response function. In psychophysics, contrast gain estimation is not straightforward. Further, rod and cone contrast gains have not been measured psychophysically at mesopic light levels where both rods...

PURPOSE To describe the clinical performance of a new dual-optic intraocular lens (IOL) with an enhanced optic profile designed to mimic natural accommodation. PATIENTS AND METHODS Prospective multicenter clinical study with the new dual-optic aspheric accommodating IOL (Synchrony Vu) in 74 patients (148 eyes) undergoing cataract surgery. Refractive target was emmetropia. Examinations at 1 mo...

PURPOSE Akreos AO and Kontur AB are two commonly used intraocular lenses (IOLs) in Iran. This study was designed to evaluate the visual performance of these lenses. METHODS In a comparative interventional study, 35 patients (70 eyes) were recruited, and each IOL was implanted in one eye of the patients, randomly. Best corrected visual acuity (BCVA), contrast sensitivity, aberrometric analysis...

The modulatory role of large-conductance Ca(2+)-activated K(+) (BK) channels in the nervous system has been extensively studied. In the retina, it has been shown that BK channels play a pivotal role in modulating feedback from A17 amacrine cells to rod bipolar cells (RBCs). Here, we used electroretinography to examine the functional role of BK channels for rod and cone vision in the retina in v...

Rod vision has a duality of organization: at mesopic luminances rod signals have access to a slow, sensitive pathway (which we refer to, following Stiles, as pi 0) and a fast, insensitive pathway (pi' 0). The phase lag between the two rod signals increases with frequency until at 15-Hz the rod signals transmitted through the two pathways emerge out-of-phase, so that destructive interference pro...