From the age of six until three years ago I was utterly dependent on very strong glasses or contact lenses to see anything much. For most of human history a person with uncorrected eyesight as poor as mine was would have been severely handicapped by it.
And it would have got worse. Five minutes before the first of the operations to correct my sight, I learned from the pre-operation check that I was in the early stages of developing a cataract in my right eye. If I had been born a century earlier or at any time before that I would have faced going completely blind in at least one eye.