January 3, 2018 -- Scientists at the NIH's National Eye Institute (NEI) report that tiny tube-like protrusions called primary cilia on cells of the retinal pigment epithelium (RPE) in the back of the eye are essential for the survival of the retina's light-sensing photoreceptors
- which decay in retinitis pigmentosa patients - differed in their fundamental structure when compared with those from family members.
A similar system of clock-driven, efferent input to eyes, with similar impacts on retinal and photoreceptor
functions, has been described in scorpions and some spiders (Heinrichs and Fleissner, 1987; Fleissner and Fleissner, 1988; Yamashita, 2002), suggesting that this feature was present in the last common ancestor of xiphosurans and arachnids.
The mutations affect the eyes' photoreceptors
, specialized cells in the retina that sense and convert light images into electrical signals sent to the brain.
Tiny projections extend from RPE cells, reach out to cover photoreceptor
cells and carry nutrients into the cells.
Structural changes in the photoreceptor
layer in OMD patients are easily detected by SD-OCT.
The ASCs reduced photoreceptor
degeneration without engraftment, which is concordant with the results of previous studies using bone marrow stem cells.
A prospective observational study was carried out on 40 eyes of 40 patients (35 males and 5 females), age ranging from 26 to 51 years to evaluate the changes in macular photoreceptor
layer using optical coherence tomography (OCT) in patients with central serous chorioretinopathy (CSC) and correlate the loss of visual acuity.
These results demonstrate that gestational lead exposure resulting in blood lead levels of 10 [micro]g/dL alters retinal development by selectively promoting the development of rod photoreceptor
cells and bipolar cells.
When a retina is degenerated, the photoreceptor
cells die and there is no message to send.
Unfortunately, there is no treatment for photoreceptor
In vertebrates, or animals with a backbone, like humans, the retina contains millions of light-sensitive photoreceptor
cells shaped like rods, which work well in dim light, and cones, which detect colors.
However, in 2002 it was shown that there is an additional and previously unknown photoreceptor
in the eye with peak wavelength sensitivity very close to the peak sensitivity of rod receptors.
Topics addressed include photoreceptor
membrane conductance, how the retinal pigment epithelium (RPE) regenerates 11-cis retinal, photoreceptor
adaptation to various levels of illumination and the biochemical basis of this phenomenon as well as its psychophysical consequences, how the retina develops into its final structure, how signals are processed in the retinal synaptic layers, and how changes in the retina and RPE influence normal aging.
THE IMPORTANCE OF PARASYMPATHETIC REGULATION OF CHOROIDAL BLOOD FLOW FOR CONE PHOTORECEPTOR
HEALTH IN PIGEONS.