the lens being too thick and curved - so that light is focused in front of the retina. Short-sightedness can be corrected by placing a concave lens in front of the eye, as shown in the diagrams below.

They can only see things that are close to them. This is because the eye refracts the light and brings it to a focus before it reaches the retina. This is corrected by using a concave or a ...

A diagram of a healthy macula ... form light-detecting or photoreceptor cells in the eye. In this study, the researchers introduced a human retina-specific protein called LN523 to cultivate ...