Abstract
Presentation Description :
Processing in the visual system is optimized to reduce information to the most relevant aspects. Different from digital cameras which read out each pixel, the output of 125 Million photoreceptors is compressed to about 1 Million fibres in the optic nerve, mainly by encoding differences in time and space, rather than absolute luminances. A major trick is the separation into ON and OFF cells which can encode small changes in time and space. They also have different specializations - OFF with smaller receptive fields and higher acuity and ON with higher contrast sensitivity. Not unexpectedly, it has been shown that they also play a specific role in emmetropization and have selective effects on eye growth and retinal dopamine release. We found that overstimulation of the OFF cells by reading conventional dark text on bright background makes the choroid thinner in only 30 to 60 minutes while reading bright text on dark background which overstimulates the ON cells makes it thicker. Exposing chickens to dynamic ON or OFF stimuli in a "chicken discotheque" we found that ON stimulation increases retinal dopamine release while OFF lowered it, compared to brightness-matched steady illumination. Since these kind of stimuli are little dependent on focus and therefore easy to control, and because text can be easily inverted on visual display units, this approach may be a new way to reduce myopia progression in school children.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.