Straylight effects with aging and lens extraction.

Purpose: To assess possible gains and losses in straylight values among the population to consider straylight as added benefit of lens extraction.

Design: In this cross-sectional design, data from a multicenter study on visual function in automobile drivers were analyzed.

Methods: On both eyes of 2,422 subjects, visual acuity (logarithm of the minimum angle of resolution [logMAR] in steps of 0.

Cortical algorithms for perceptual grouping.

A fundamental task of vision is to group the image elements that belong to one object and to segregate them from other objects and the background. This review provides a conceptual framework of how perceptual grouping may be implemented in the visual cortex. According to this framework, two mechanisms are responsible for perceptual grouping: base-grouping and incremental grouping.

Cannabinoid agonist WIN 55212-2 speeds up the cone response to light offset in goldfish retina.

Goldfish cones contain CB1 receptors at the synaptic terminal, selectively accumulate 3H-anandamide, and contain fatty acid amide hydrolase-immunoreactivity, and voltage-gated calcium and potassium currents are modulated by CB1 ligands (Yazulla et al., 2000; Fan & Yazulla, 2003; Glaser et al., 2005).

Pseudoxanthoma elasticum: the end of the autosomal dominant segregation myth.

Pseudoxanthoma elasticum (PXE) is a heritable connective-tissue disorder affecting the eye, skin, and vascular system. Recent publications show that PXE exclusively segregates in an autosomal recessive fashion. However, the lack of an internationally accepted clinical "gold standard" for PXE, our incomplete knowledge of PXE etiology, and the incomplete nature of some molecular, clinical, and environmental studies warrant further investigation.

Attention lights up new object representations before the old ones fade away.

We investigated how attention shifts from one object to another by recording neuronal activity in the primary visual cortex. Monkeys performed a contour-grouping task in which they had to select a target curve and ignore a distractor curve. Some trials required a shift of attention, because the target and distractor curves were switched during the course of the trial.

Biometry of phakic intraocular lens using Scheimpflug photography.

Purpose: To examine lateral and axial positioning of phakic intraocular lenses (IOLs) with iris fixation in the anterior chamber and to examine short-term stability of the IOL position.

Setting: The Netherlands Opthalmic Research Institute, Amsterdam, the Netherlands.

Methods: Thirty patients participated in the study.

Wavelength dependence of intraocular straylight.

Wavelength dependence of retinal straylight has been a mystery since Stiles in 1929 [Stiles,W.S., 1929.

Identification of mutations in the AIPL1, CRB1, GUCY2D, RPE65, and RPGRIP1 genes in patients with juvenile retinitis pigmentosa.

Objective: To identify mutations in the AIPL1, CRB1, GUCY2D, RPE65, and RPGRIP1 genes in patients with juvenile retinitis pigmentosa.

Methods: Mutation analysis was carried out in a group of 35 unrelated patients with juvenile autosomal recessive retinitis pigmentosa (ARRP), Leber's congenital amaurosis (LCA), or juvenile isolated retinitis pigmentosa (IRP), by denaturing high performance liquid chromatography followed by direct sequencing.

Results: All three groups of patients showed typical combinations of eye signs associated with retinitis pigmentosa: pale optic discs, narrow arterioles, pigmentary changes, and nystagmus.

VAMP5 and VAMP8 are most likely not involved in primary open-angle glaucoma.

Purpose: To select and characterize novel POAG disease genes. On the basis of genetic position (GLC1B), expression in the optic nerve, and biochemical function (targeted membrane transport processes), we selected the human VAMP5 and VAMP8 (encoding vesicle-associated membrane proteins 5 and 8) as potential candidate disease genes for POAG. We subsequently analyzed whether or not sequence changes in VAMP5 or VAMP8 were implicated in POAG.

Neural responses in cat visual cortex reflect state changes in correlated activity.

Cortical state is characterized by ongoing rhythmic neural activity. Changes in rhythmic activity and thus in cortical state are shown to occur spontaneously in the anesthetized cat. We were interested in whether these state changes have an affect on the cortical processing of sensory stimuli.

Disruption of Abcc6 in the mouse: novel insight in the pathogenesis of pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE) is a heritable disorder of connective tissue, affecting mainly skin, eye and the cardiovascular system. PXE is characterized by dystrophic mineralization of elastic fibres. The condition is caused by loss of function mutations in ABCC6.

Elemental operations in vision.

Many cognitive tasks are serial in that they require several steps that have to be carried out in a sequence. Here, I outline a new theory of how these processing steps are implemented in vision by networks of neurons that span several areas of the cerebral cortex. The theory explains how individual neurons can contribute to the elementary processing steps, and also how several processing steps can be arranged in a sequence to form more complex visual routines, just as computer programs can be composed of sequences of instructions.

Synchrony dynamics in monkey V1 predict success in visual detection.

Behavioral measures such as expectancy and attention have been associated with the strength of synchronous neural activity. On this basis, it is hypothesized that synchronous activity affects our ability to detect and recognize visual objects. To investigate the role of synchronous activity in visual perception, we studied the magnitude and precision of correlated activity, before and after stimulus presentation within the visual cortex (V1), in relation to a monkey's performance in a figure-ground discrimination task.

Heterogeneity of the genetic risk in age-related macular disease: a population-based familial risk study.

Objective: To assess the extent of heterogeneity of the genetic risk of age-related macular disease (AMD) among families.

Design: Case-controlled population-based familial aggregation study.

Participants: Participants comprised 190 first-degree relatives of 65 case probands and 347 relatives of 100 control probands.

The involvement of glutamate-gated channels in negative feedback from horizontal cells to cones.

Photoreceptors are the light sensitive cells in the retina. They project to horizontal cells and bipolar cells via a glutamatergic feed forward pathway. Horizontal cells are strongly electrically coupled and integrate in that way the input from the photoreceptors.

Cobalt ions inhibit negative feedback in the outer retina by blocking hemichannels on horizontal cells.

In goldfish, negative feedback from horizontal cells to cones shifts the activation function of the Ca2+ current of the cones to more negative potentials. This shift increases the amount of Ca2+ flowing into the cones, resulting in an increase in glutamate release. The increased glutamate release forms the basis of the feedback-mediated responses in second-order neurons, such as the surround-induced responses of bipolar cells and the spectral coding of horizontal cells.

Crumbs homologue 1 in polarity and blindness.

Several retinal dystrophies, including retinitis pigmentosa type 12 and Leber congenital amaurosis, are caused by a large variety of mutations in the CRB1 (Crumbs homologue 1) gene. This discovery led to an increased focus on the function of CRB1 and the Drosophila homologue Crumbs. In the present study, we review the current knowledge on Crumbs and its vertebrate homologues, their function in cell polarity and their pathogenicity in retinal degeneration.

Ephaptic interactions within a chemical synapse: hemichannel-mediated ephaptic inhibition in the retina.

The two best-known types of cell-cell communication are chemical synapses and electrical synapses, which are formed by gap junctions. A third, less well known, form of communication is ephaptic transmission, in which electric fields generated by a specific neuron alter the excitability of neighboring neurons as a result of their anatomical and electrical proximity. Ephaptic communication can be present in a variety of forms, each with their specific features and functional implications.

Visual information transfer across eye movements in the monkey.

During normal viewing, the eyes move from one location to another in order to sample the visual environment. Information acquired before the eye movement facilitates post-saccadic processing. This "preview effect" indicates that some information is maintained in transsaccadic memory and combined with information acquired at the next fixation.

Synchrony and covariation of firing rates in the primary visual cortex during contour grouping.

The visual system imposes structure onto incoming information, by grouping image elements of a single object together, and by segregating them from elements that belong to other objects and the background. One influential theory holds that the code for grouping and segmentation is carried by the synchrony of neuronal discharges on a millisecond time scale. We tested this theory by recording neuronal activity in the primary visual cortex (area V1) of monkeys engaged in a contour-grouping task.

Crumbs homologue 1 is required for maintenance of photoreceptor cell polarization and adhesion during light exposure.

Loss of Crumbs homologue 1 (CRB1) function causes either the eye disease Leber congenital amaurosis or progressive retinitis pigmentosa, depending on the amount of residual CRB1 activity and the genetic background. Crb1 localizes specifically to the sub-apical region adjacent to the adherens junction complex at the outer limiting membrane in the retina. We show that it is associated here with multiple PDZ protein 1 (Mupp1), protein associated with Lin-7 (Pals1 or Mpp5) and Mpp4.

Correlates of transsaccadic integration in the primary visual cortex of the monkey.

We make several eye movements per second when we explore a visual scene. Each eye movement sweeps the scene's projection across the retina and changes its representation in retinotopic areas of the visual cortex, but we nevertheless perceive a stable world. Here we investigate the neuronal correlates of visual stability in the primary visual cortex.

A new three-dimensional model of the organization of proteoglycans and collagen fibrils in the human corneal stroma.

The purpose of the present study was to re-evaluate the three-dimensional organization of collagen fibrils and proteoglycans (PGs) in the human corneal stroma using an improved ultrastructural approach. After a short aldehyde prefixation, one half of seven fresh corneal buttons was stained for PGs with Quinolinic Phtalocyanin (QP) or Cupromeronic Blue (CB). Strips of 1 mm width were cut, subsequently treated with aqueous phosphotungstic acid (PTA) and further processed for light and electron microscopy.