Go to Google Groups Home    sci.med.vision
Re: Stay away from "vision educators"

Kevin <lite...@googlemail.com>

In article <2zEYa.1631$vo2....@newsread1.news.atl.earthlink.net>,
mty...@mindspring.com says...

> Bates: "ALL glasses contract the field of vision to a greater or less degree."
> Patently false. Minus spectacle lenses can increase the field of vision. They
> don't always, but they certainly can be made to. Minus lenses minify, and more
> objects are "drawn into" the field.

The area of useful sight for a person wearing glasses is reduced by
the simple fact that glasses do not extend to the edges of the visual
field. To say that more objects are drawn into the field skips the
point.

There are areas of visual information at the outer edges of the sight
which become discarded by the person wearing glasses. Frames
themeselves block light rays, and all rays beyond the edges of the
frames are no longer perceived as useful. The retina thus becomes
accustomed to working effectively over a contracted area. To say Minus
lenses minify is quite correct, - they draw more information into an
area of sight that has been contracted.

It is well known that in general all myopes have a deterioration at
the very edges of the retina as compared to people who have not worn
glasses.

An optometrist assumes that the deterioration is a result of being
myopic. I would suggest that the fact that the person is trained into
using a smaller area of the retina should not be ignored.

Kevin