New cell links myopia to childhood spent indoors

It’s believed the newly identified type of retinal ganglion cell, which is highly sensitive to light, could cause myopia when it becomes dysfunctional.Researchers from Northwestern University’s Feinberg School of Medicine said the cell controls how the eye grows and develops and have linked the rising frequency of myopia with time spent away from natural light.{{quote-A:R-W:480-I:2-Q: The eye needs to stop growing at precisely the right time during childhood, -WHO:Greg Schwartz, Assistant Professor of Ophthalmology}}If the cell causes the eye to grow too long, images do not get focused properly on the retina, resulting in myopia.Lead investigator Associate Professor Greg Schwartz said the team is hopeful their discovery could change treatment methods to better control the condition early on.“The eye needs to stop growing at precisely the right time during childhood,” Schwartz said.“But for years no one knew what cell carried the signal. We have potentially found the key missing link – which is the cell that actually does that task and the neural circuit that enables this important visual function.”The scientists named the cell “ON Delayed”, which according to Schwartz, was a reference to the cell’s slow responses to bright light. The cell stood out among the rest due to its hypersensitivity when the eyes focused on an image.{{quote-A:L-W:450-Q: For years no one knew what cell carried the signal. We have potentially found the key missing link }}The cells are part of the neural circuit that is wired to other cells in the retina where it manifests its sensitivity to light.According to the study, too much time spent indoors could cause aberrant overgrowth of the eye as the indoor light spectrum has higher levels of red and green contrasts. These colour contrasts are the same with the artificial contrast image on the retina, which could overstimulate the cells to cause the anomaly.To measure this, the researchers, used microscopic glass electrodes to record electrical signals from cells in a mouse retina while presenting patterns of light on a digital projector.The next part of the research is to find the gene for this particular retinal cell.