The morphology and spectral absorption characteristics of the retinal photoreceptors in the southern hemisphere lamprey Geotria australis (Agnatha) were studied using light and electron microscopy and microspectrophotometry. The retinae of both downstream and upstream migrants of Geotria contained two types of cone photoreceptor and one type of rod photoreceptor. Visual pigments contained in th...

PURPOSE To examine highly localized photoreceptor disruptions in the fovea by a high-resolution adaptive optics (AO) fundus camera combined with Fourier-domain optical coherence tomography (FD OCT). DESIGN Observational case series. PARTICIPANTS Three eyes of 3 patients who showed dark foveal spots by slit-lamp biomicroscopy. METHODS Three patients who reported metamorphopsia but showed n...

We investigated the effects of photoreceptor degeneration on the anatomy and physiology of inner retinal neurons in a mouse model of retinitis pigmentosa, the retinal degeneration (rd) mutant mouse. Although there is a general assumption that the inner retinal cells do not suffer from photoreceptor death, we confirmed major changes both accompanying and after this process. Changes include sprou...

Photoreceptor death is the endpoint of many blinding diseases. Identifying unifying pathogenic mechanisms in these diseases may offer global approaches for facilitating photoreceptor survival. We found that rod or cone photoreceptor-specific deletion of nicotinamide phosphoribosyltransferase (Nampt), the rate-limiting enzyme in the major NAD(+) biosynthetic pathway beginning with nicotinamide, ...

The transcription repressor Tramtrack (TTK) is found in cone cells but not photoreceptor cells of the Drosophila eye. We show that down-regulation of TTK expression occurs in photoreceptor cells and is required for their fate determination. Down-regulation requires the presence of Phyllopod (PHYL), which is induced by the RAS pathway, and Seven In Absentia (SINA). Loss of either gene causes acc...

Vision represents one of the main senses for humans to interact with their environment. Our sight relies on the presence of fully functional light sensitive cells - rod and cone photoreceptors - allowing us to see under dim (rods) and bright (cones) light conditions. Photoreceptor degeneration is one of the major causes for vision impairment in industrialized countries and it is highly predomin...

Photoreceptor noise sets an absolute limit for the accuracy of colour discrimination. We compared colour thresholds in the honeybee (Apis mellifera) with this limit. Bees were trained to discriminate an achromatic stimulus from monochromatic lights of various wavelengths as a function of their intensity. Signal-to-noise ratios were measured by intracellular recordings in the three spectral type...

Pre-clinical studies provided evidence for successful photoreceptor cell replacement therapy. Migration and integration of donor photoreceptors into the retina has been proposed as the underlying mechanism for restored visual function. Here we reveal that donor photoreceptors do not structurally integrate into the retinal tissue but instead reside between the photoreceptor layer and the retinal...

Light-induced photoreceptor apoptosis occurs in many forms of inherited retinal degeneration resulting in blindness in both vertebrates and invertebrates. Though mutations in several photoreceptor signaling proteins have been implicated in triggering this process, the molecular events relating light activation of rhodopsin to photoreceptor death are yet unclear. Here, we uncover a pathway by wh...

Injection of basic fibroblast growth factor (bFGF) into the eye, intravitreally or subretinally, delays photoreceptor degeneration in inherited retinal dystrophy in the rat, as does local injury to the retina (Faktorovich et al., 1990). To determine whether this heparin-binding peptide or local injury is effective in any other form of photoreceptor degeneration, we examined their protective rol...