Why is the human retina so large?

[fluidistic]

Apparently the retina of humans covers about 65% of the surface of the interior of our eyes.
But most light is focused around the fovea centralis and if it isn't focused around there, we lose resolution. I understand that at night it's better not to focus too close to the fovea centralis but still, I see no way that light somehow ever reaches maybe 40% or 50% of cone and rod cells.
Am I missing something? Why do we have a so large retina?

 

[mfb]

But most light is focused around the fovea centralis

Is it? The light from the center of our field of view, sure. The light from other directions is not.
We lose resolution, but it is still sufficient to see moving things - and in general, something that moves is very interesting and you don't want to miss it.

 

[fluidistic]

Is it? The light from the center of our field of view, sure. The light from other directions is not.
We lose resolution, but it is still sufficient to see moving things - and in general, something that moves is very interesting and you don't want to miss it.

That explains everything, thanks. I just tested with my finger and I all makes sense now, I guess almost all or all cones indeed get light.