The first is to have an irregularly shaped eye ball. This will mean that light a distant object falls on a closer part of the retina than light from a nearer object. With the eye in the correct position both distant and close objects can be in focus at the same time. This is how the eye of a horse works. A horse spends most of its life with its head down eating, it doesn't need to change it view of the world much and it is very useful for it to be able to see predators on the horizon at the same time as the grass at its feet.
Humans however use a different method.
Natures second solution is to have a flexible lens and muscles attached to it. By changing the shape of the lens you change the angle of refraction of the light passing through the lens and thus move the point of focus closer to or further away from the lens. This system is much more useful for animals that need accurate images of different parts of the world all the time, such as hunters. Animals like horses can adjust the shape of their lenses as well but not to the extent that we can. These pages are here free for you to use, I would like to keep them that way, however making and running this site, and the other sites I am currently making or have made, on Birds, Mammals, Insects and Fish and Bacteria costs money.