As babies start perceiving and recognizing thing the brain stores those connections so pretty soon one image is become "Bringer of food" later "bringer of comfort and protection and food" and that of course is mummy.
Recognizing daddy takes a bit longer but pretty soon the kid has learned the familiar stuff and as their perception widens so does their brain learn the visual stimuli which stands them in good stead for the next and more challenging of visual tasks that a child must face come 4 to six and that is recognizing squiggles as letters and numbers.
The latter is of course is not a natural learning thing and must be taught. As must the interpretation of sounds into meaning and the learning to articulate meaningful sounds from gurgles and squeaks into meaningful words. The point is that, beyond the basic talents we are naturally give, that of sight, hearing, smell, articulation and touch the actual refinement of these is a learned ability. And much of it has to be taught.
Children who grow up in a stimulus rich environment are more likely to learn advanced reading skills and to do more complicated mathematics than a child who grows up in a grey featureless place. It is the same with music. There is a known connection between musical ability and mathematics (Mathematicians all seem to appreciate JS Bach). These are all learned things.
As far as visual acuity goes there have been shown to be nerve endings in the visual optic nerves and visual cortex which, when stimulated correctly multiply and improve in ability. Some humans train themselves when fairly young to observe very fine detail and that ability and training has meant that there are a lot more active nerve endings receiving and translating visual signals than there are in the average population.
But these nerve ending can forget or shrivel away too. With advancing age it is very common for one to lose the ability to distinguish characters close up. It is almost like a good movie has deteriorated and become 'grainy'.
It is possible to re-train the brain and re-stimulate the visual cortex so that many of these aging effects are reversed.
If one is keen on improving eyesight without having to use corrective lenses or contacts and avoiding the need for the laser "pizza cut" treatment then there is a course of therapy available. It is totally non intrusive and consists of a series of special exercises while looking at specific images. In this manner, and following the instructions one is able to, in something like 80% of all cases significantly improve one's eyesight and reading ability. In successful cases many patients have been able to totally dispense with their reading glasses.
GlassesOff is one product which makes naturally a distinct possibility, relieving users of the need for eyeglasses or contact lenses.