“If you would be a reader, read; if a writer, write” — that’s how Epictetus saw the ideal state of affairs back in the 1st century AD. Having failed to comply with his expectations we all read and write nowadays, so learning a bit more about how we read, would do no harm for us as readers and as writers.
How it starts
It is generally agreed that whenever we sit down to read our eyes first of all distinguish shapes of greater and lesser illumination, i.e. letters vs. background; the reflection of these patterns falls in the retina as an inverted image1. When we read our eyes move in jumps (saccades) followed by still periods (fixations); it’s during fixations that information is perceived (up to 15 chars to the right and 3-4 to the left (for languages that read from left to right)); regressive eye movements are available if we need to re-check something. The fovea2 having higher concentration of cones3, the foveal field (about 7 central chars) is best available for perception. The parafoveal area and the periphery are mainly used to detect larger patterns on the page. Visual patterns are further conveyed through the optic nerve to the brain for interpretation4 (the right half of the visual field of each eye goes to the left hemisphere, and vice versa). The degree of localization of brain functions is still unclear, but it is recognized that visual input is mainly processed in the back part of the occipital lobe.
Footnotes:
1Letter-background colour combinations may be either reader-friendly or not; in addition to that they may or may not foster attention-getting (Veide, M.).
2 Central area of each retina.
3Each eye has about 130 million photoreceptors of 4 types: rods and 3 types of cones. Cones are better for detailed analysis of form and colour; rods are more effective for blurred images in shades of grey.
4It is important to note that written language unlike other objects, which human eye may have to encounter, has a conventional structure of the graphic signal, i.e. there is a limited number of signs (letters). Such conventionality of patterns makes it easier for humans to process written texts.