- Myopia or nearsightedness is an
eye disorder, which affects more than one billion people worldwide.
- A newly discovered cell in the
retina called 'ON Delayed' is over stimulated by indoor light spectrum,
- This discovery could pave the way
for developing new treatments for myopia.
A cell in the
retina that may cause myopia
dysfunctions has been identified by a research team at the Northwestern
Medicine. The dysfunction of the cell is linked to the duration of time a child
spends indoors, staying away from natural light.
discovery could lead to a new therapeutic target to control myopia," said
Greg Schwartz, lead investigator and assistant professor of ophthalmology at
Northwestern University Feinberg School of Medicine.
‘The newly discovered retinal cell called ‘ON Delayed’ could be a new therapeutic target to treat myopia.’
Myopia Cell in Retina
discovered in the retina is highly sensitive to light and controls how the eye
grows and develops.
The eyes need to stop growing
at the right time during childhood. But, if the newly discovered cell instructs
the eye to grow long, the images fail to be focused on the retina, which causes
nearsighted vision and the individual may require
corrective glasses or contact lenses for a lifetime.
There are about
50 types of retinal ganglion cells, which convey all the information to
perceive the visual world. Each cell provides different visual information such
as color or motion.
contains a signal to focus the image in the eye. The signal plays a key role in
regulating eye growth during childhood.
years no one knew what cell carried the signal. We 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," said Schwartz.
The cell has
been named as "ON Delayed" because of its slow responses to lights becoming
The ON Delayed cell is unique in its
exquisite sensitivity to whether an image was in focus. The research team
described how the cell is wired to other cells in the retina to acquire the
Too Much Time Indoors
may Trigger Myopia
Too much indoor
time can trigger myopia, said the research team. The indoor light spectrum has
high red and green contrast which activate the clusters of photoreceptors in
the eye. This can create the equivalent of an artificial contrast image on the
Delayed retinal ganglion cell is overstimulated by such patterns, which cause
aberrant overgrowth of the eye, leading to myopia.
published in the Current Biology
was conducted by Schwartz and co-author
Adam Mani, a postdoctoral fellow in ophthalmology at Feinberg.
glass electrodes were used to record the electrical signals from cells in a
mouse retina, while presenting patterns of light on a digital projector.
team hopes to find a gene specific to the On Delayed cell. In future studies,
the cells activity can be turned up or down in a genetic mouse model to try to
induce or treat myopia.
research is a part of another larger body of research that aims to reverse
engineer the retina by identifying new retinal cell types in mice.
The research was
funded by the National Institutes of Health (NIH). Schwartz wants to identify
the new cells by their specific function, genetic signatures and understand how
the cells are interconnected within the retina and the targets in the brain.
could lead to gene therapy to treat blindness and improve the function of
artificial retinal prosthetics.
Myopia is a
common type of refractive error where close objects appear clearly whereas
distant objects appear blurry. It is a refractive error in which the eye does
nor refract light properly to a single focus to see images clearly.
than one billion people have myopia. The incidence of myopia is rising and is
linked to the time duration people spend indoors as children. Myopia is
identified in children between the ages 8 and 12 years old. Myopia worsens
during the teenage years.
- Adam Mani, Gregory W. Schwartz. Circuit Mechanisms
of a Retinal Ganglion Cell with Stimulus-Dependent
Response Latency and Activation
Beyond Its Dendrites. Current Biology (2017) DOI:
What Is Myopia? - (https://www.aao.org/eye-