more exercise may prevent myopia #health #eyes

news.health/eyes/more exercise may prevent myopia:
7.3: 12.29: summary:
. this study is consistent with the theory that
myopia is related to high blood sugar
that is causing hypergrowth of the cornea;
but the study didn't prove the theory .

Invest Ophthalmol Vis Sci 2008:
"Previous studies have shown that university students,
particularly medical students, are at risk of developing
adult-onset myopia during their university studies,
perhaps as a result of extensive studying”
. myopic development or progression in medical students
is more likely in their early 20s
than in their late 20s.
. two-year longitudinal cohort study:
“Our study shows that the average amount of time
spent on physical activity
is just one hour per day . . . and suggests that
increasing this amount of time by another hour per day
can prevent the average myopisation that the students experience."
this study is observational, and therefore,
"to establish a true cause-and-effect relation
between myopia and physical activity,
an intervention-study will need to be done."
[ otherwise we can't rule out that
the same condition that causes myopia
also causes a tendency to avoid exercise,
and when required to exercise,
the problem may still be there .]