I can speak for the Romans.
Visual impairment (and indeed blindness) were relatively common in Ancient Rome. They had to deal with diseases such as cataracts, degeneration of vision in old age, and injuries, whether at battle or at work—imagine mining, blacksmithing, or glassblowing without eye protection!
In the case of those who had their eyesight and then lost it, the reactions run the gamut. On one hand, Suetonius reports that Gallus Cerrinius, a Roman senator who suddenly lost his eyesight, was so distraught he would have starved himself to death if Augustus had not talked him out of it. But most just looked at it as a minor nuisance. Cicero discusses some examples of how being blind did not prevent people from going about their business:
But thinking in the case of a wise man does not altogether require the use of his eyes in his investigations; for if night does not strip him of his happiness, why should blindness, which resembles night, have that effect? For the reply of Antipater the Cyrenaic to some women who bewailed his being blind, though it is a little too obscene, is not without its significance. “What do you mean?” saith he; “do you think the night can furnish no pleasure?” And we find by his magistracies and his actions that old Appius, too, who was blind for many years, was not prevented from doing whatever was required of him with respect either to the republic or his own affairs. It is said that C. Drusus’s house was crowded with clients. When they whose business it was could not see how to conduct themselves, they applied to a blind guide.
In short, unlike other physical disabilities such as dwarfism, curvature of the spine, etc., visual impairment did not often have a negative connotation in Ancient Rome. For the day-to-day activities of getting around town, they would have family members or slaves help them carry out their business. But to answer your question, "How did they live their lives?"—they just did.
Many consider the Medieval Islamic Empire to be one of the first societies to make serious inroads into opthamology. The Alteration of the Eye by Yuhanna ibn Masawaiyh (777-857) is the earliest text on opthamology.
An Iraqi named Ammar bin Ali Al Mawsili in Egypt developed a method for extracting soft cataracts, suctioning them using a hollow metal syringe in 900AD.
Follow up question: Is it true that people with myopia (nearsightedness) used to work in professions requiring a good ability to see small things (e.g., watchmakers)? Due to being able to see things close to the eyes better than normal sighted people.
I was very interested to find out that Queen Elizabeth I was short (or near) sighted.
From the Annals of Elizabeth by John Hayward,
"She was a lady, upon whom nature had bestowed, and well placed, many of her fairest favours... her hair was inclined to pale yellow, her forehead large and fair, a seeming seat for princely grace; her eyes lively and sweet, but short-sighted..."
edit: Another source. I can't figure out how to copy/paste this text, but here are two short quotes concerning Elizabeth's eyesight. It's all I can find at the moment, sorry mods. :(
It has been suggested that it was this inability to see people at a distance that made Elizabeth so eager to be up close and personal with her people; she literally couldn't see them unless they were that close. Contemporaries of the Queen also commented on her "openness" of expression, which has been interpreted by some historians as the unfocused eyes of a person with extreme nearsightedness. Even though it may be viewed as a handicap to most, Elizabeth seemed to be able to turn all of her characteristics into a positive. Being so friendly and close to her subjects was part of what made her a popular queen.
In lieu of other input, I'll link to times this question has been asked previously: http://www.reddit.com/r/AskHistorians/wiki/health#wiki_eyesight.2C_glasses.2C_and_contact_lenses
Not a historian, but I took a class with Randy Nesse, who has interests in the evolution of disease (as in, why hasn't evolution fixed certain diseases?), and he raised this question, and actually in hunter gatherer societies rates of nearsightedness are much lower. Basically, his explanation (which is debatable, as are most explanations that come from evolutionary psychology), was that modern lifestyles put a lot of strain on the eyes (notably reading), which results in higher rates/severity of sight problems than would have been seen in early humans.
Follow-up question, if I may: Is there any documentation of dogs being used as they are today (seeing eye dogs)?