About this Research Topic
Photoreceptors and other central nervous system cells are considered post-mitotic and at their maximum numbers before birth. To provide decades of vision, these neurons must have inherent repair processes and be supported and renewed by glial and other cells. There are limitations to the extent of support available to photoreceptors, especially given their high metabolic rates, the assault by incident light on the retina, and the need for optical clarity that constrains the numbers and locations of blood vessels. Further, these support systems can fail with aging and disease, creating a harsh microenvironment for extended cone survival. Cones have a remarkable ability to survive, compared with rods, but with alterations in their structure and function, enabling them to stay connected in their circuitry to provide at least some vision. Improving the microenvironment in aging and disease has the potential to preserve cones and visual system circuitry, thereby preserving vision.
The remarkable resiliency of cones, and possibly other visual system neurons, has gone largely unappreciated. It is well known that cones develop long stacks of outer segments to capture light, but the length greatly increases after birth or in adulthood after retinal detachment. Unfortunately, much of the histology for several of the human disease such as age-related macular degeneration is heavily weighted towards very old eyes and end-stage disease. New technologies have enabled in vivo assessments of photoreceptor health with the added advantages of enabling investigations of younger subjects with earlier stage disease and longitudinal studies of disease progression. This special issue will solicit articles that carefully inspect the photoreceptor microenvironment in health, disease, treatment, and aging, using a variety of techniques including histology and in vivo imaging both in human eyes and visual pathways, as well as animal models. Differences between cones and rods, and general properties of visual system neurons will be sought. We expect this issue will fill a gap in recent literature to better understand photoreceptor survival within the retinal microenvironment and how this microenvironment sustains vision throughout a lifetime.
We welcome Original Research, Methods, Review, Mini Review, Hypothesis and Theory, Perspective, Clinical Trial, Case Report, Conceptual Analysis, Data Report, Brief Research Report, General Commentary, Opinion, Technology and Code, on the following subtopics:
• Cone and other visual system neuron survival and function in aging and disease: in vivo or ex vivo human or animal model; structure and/or function; remodeling
• Comparing two diseases; aging vs. disease; comparisons with other measures such as vascular data
• Alteration of neural cells or their microenvironment by gene therapy, stem cell transplantation, or pharmacological agents: human data including clinical trials, surgery or drug therapy, planned or serendipitous; or animal models
• Re-analysis of histological data with cone cell bodies or other visual neurons, early vs. end-stage changes to glia, distinguishing neural vs. glial (Mueller) cell bodies or cones vs. rods
• Technology, code and/or datasets used to assess cone or other visual system neuron numbers, distribution, layer thicknesses
• Imaging and electrophysiology techniques or models
Dr. Morgan’s lab receives financial support from AGTC. Dr. Elsner is the CEO and founder of Aeon Imaging. The other Topic Editors declare no competing interests with regards to the Research Topic theme.
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.