Minus or Plus lenses are ALWAYS wrong.

Wearing a minus lens that is too strong produces the equivalent of
hyperopia.  This can lead to all the various issues related to uncorrected
hyperopia, such as asthenopic symptoms, esophoria/esotropia, etc.  If the
optical centers of the lenses do not have the proper relationship with the
interpupillary distance, prism is induced.

Some pediatric eye specialists believe that it is desirable to undercorrect
hyperopia in a child in order to encourage the eyes to become emmetropic,
i.e. move in the direction of less hyperopia and more myopia.  At least one
multi-center, longitudinal study does not support this idea.

Laboratory studies indicate that prescribing either plus or minus lenses
way in excess of the refractive status of some species of young mammalian
species will induce refractive error.

There is at least one valid reason for prescribing minus slightly in excess
of the patient's refractive error, and that is to treat convergence
insufficiency by stimulating accommodative-convergence.

DrG

Patients with A high myope >= -6.00D, have a higher incidence of potencially
blinding eye diseases. It is therefore important to have an eye exam to
exclude any of these diseases. Having said that, hyperopic and presbyopic
patients are now able to (although not always) purchase a pair of spectacles
from the drug store without ever having an eye exam. My concern is greater
for the older presbyopes, since they have reached an age where more eye
problems are seen.

Short sighted drivers can hurt others on the road, overprescribed lenses
which are not centered correctly can make a driver fatigue easily,
Underprescribed lenses can slow down reaction times.  Passing the DMV 20/40
test says nothing about the quality of vision or the visual fields.

So yes, they may not hurt their eyes but they can hurt themselves and
others.

Roland J. Izaac

--

  I have no doubt that the standard way to get glasses is
better, but I am now living in a situation where I can
hardly get out, and my Rx is changing monthly.  I would
like to renew my glasses about every 3 months.  I know my
pupil spacing.  I have been using combinations of old
glasses with overlays of reading glasses to be able to read
or see distance at all.  Ordering by mail may not be good,
but it has to be better than what I have now.  Frame fit
hardly even ranks as a problem.

I would appreciate it if you could answer the practical
questions I asked.

Thanks.

Jack