Human Eyes Have In-Built Night Vision: Study

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A new study finds human eyes have in-built night vision mode as the retina changes the hardware as well as software of light sensing cells to make comfortable seeing under starlight and moonlight.

Earlier it was believed retinal circuits does not change and are programmed for specific tasks. Now it is found the retina reprograms itself for low light too.

Duke University assistant professor Greg Field said, “To see under starlight, biology has had to reach the limit of seeing an elementary particle from the universe, a single photon.”

Published in the journal Neuron, the findings reveal the reprogramming of retinal circuits takes place in the retinal cells that are motion sensitive as in very good light too, for most of the animals, identifying direction of a moving object is key to survival.

The researchers said there are four kinds of motion-sensitive cells in the retinas of vertebrates and each one is specifically responsive to motion. However, such directional neurons in human eyes account for 4 percent of the cells for sending signals to the brain.

In lab test with mouse retinas it was found the retinal cells change behavior in low light.

Human patients with vision loss mostly complain of loss of motion perception and Field said the new study may help in the designing of implantable retinal prosthetics.