my wild guess is... they zzz early and woke up early... only the
really hardworking ones studied in the moonlight/use candles.. so
most of them had gd eyesight...
everywhere around them got trees n green plants... gd for
eyes... now only buildings n roads n some pathetic tiny plants that
line the streets...
on top of that, they did a lot of farming/gardening...
self-sufficient supply of herbs for eyes n body.. the women dont
work then so they spent hrs brewing herbal soup... healthy and
inexpensive...
life wasnt so stressful then... stress affects health...
including eyesight i think...
not forgetting bks, tv, psp, computer, etc...
ozone layer almost gone so more powerful rays... spoil our
eyes..
the list goes on..
conclusion: life was certainly less complex n less stressful
then.. but more enjoyable with greater entertainment such as ktv
and wii now..
try to enjoy our era while we are still here... lol