Can the human eye evolve to see better in the dark?

Answer

The human eye is one of the best in nature in terms of performance. In terms of sharpness we are only inferior to the birds of prey, in terms of sensitivity or visibility in the dark we are only inferior to nocturnal animals.

We got our eye from the primates. it has had the current level of performance for several tens of millions of years, because the other great apes also have similar eyes.

So you can assume that the current eye is “optimal” for the use that the primates make of it. But Primates are not pure nocturnal animals.

Suppose that we as a population were going to live in the dark or in the twilight. What would happen? The following is purely hypothetical:

-this evolution would take hundreds to tens of thousands of generations.

-possibly the cones in the retina would disappear, cones that are responsible for daylight vision and also color vision. the retina would only consist of rods that are more sensitive in the dark, but do not provide color vision. The rods may become more numerous to increase the eye’s acuity, but they may also become larger to capture more light, which in turn degrades the eye’s acuity. The biochemistry of the rods will change to an optimal point in low light.

-Alternatively, the cones may evolve to a higher sensitivity to be more suitable in dark environments. This becoming more sensitive will be accompanied by the larger cones (capturing more light), and thus reducing the sharpness of vision.

What will most likely evolve is the size of the lens of the eye, the opening of the iris and the size of the eyeball. A larger lens and aperture, necessarily contained in a larger eye, captures more light and improves night vision proportionately.