Seeing everything new/Dominant Eyes

[Richard Clompus <rclompus@voicenet.com>]

Donal Philby wrote:
<snip>
Richard,
As an OD, maybe you can help with question I have.  When I was younger I
was right eyed and everything was wonderful.  I could see fine detail close
up.  Eventually, I needed glasses for distance.  Recently I need correction
for distance still and a slight help for closeup.  

Somewhere along the line I switched to being left eyed.  It happened during
a period in my life when I was not shooting much and writing for a living.
But being left eyed is really a irritation, especially without a motordrive
on a M camera.

When I look with my right eye, I can focus okay, it just doesn't register
with my brain the same way.  Does it have to do with bilateral brain??
Most importantly, is there anyway to work a switch back to being right eyed
so the Ms are easier to use???
<snip>

Answer:
Dear Donal,

Each of us is born with a dominant eye - much like a dominant hand.  Some
of us are ambidextrous but most of us have a strong tendency to favor one
eye or the other for activities that only permit one eye.  You can test for
eye dominancy by using an 8X10 sheet of paper with a one inch hole cut in
the middle.  Put on your distance glasses and hold the card with  both arms
stretched out so that you are viewing an object about 20 feet away.  Now
close the right eye?  Did the object disappear?  Next again view the object
with both eyes open and then close the left eye.  Did the object disappear?
 Which ever eye you closed caused the object to disappear - was your
dominant eye.  Your brain will automatically line up the eye that is dominant.

Think of the brain as being hard wired when it develops a preference for
the dominant eye as young as age 4.  If your dominant eye had more
nearsightedness, farsightedness or astigmatism than your non-dominant eye,
the non-dominant eye may actually be clearer than the dominant eye.  Your
visual system being very adaptive may permit you to function favoring the
non-dominant eye.  Most of this dominant information never becomes apparant
since most of us keep both eyes open when viewing things.  With
photographers - all bets are off.  You have to use one eye to view through
most viewfinders.  

My recommendation is to use the distance correction in a  pair of glasses
or contact lenses for most 35mm and MF viewfinders.  Ground glass with a
view camera demands more focussing that requires greater near correction.
Sometimes we can adapt to using the non-dominant eye rather than the
dominant eye for focusing.  It won't hurt you to use either eye for
focussing.  Use which ever is more comfortable.  

I hope this has been helpful.  It can be awfully confusing when putting all
of this in writing.    And some people seem to be exceptions to these
observations.  Maybe I'll convince Leica to make a 8X10 white plastic card
with a red Leica logo on it with a centrally located  one inch "air lens"
(hole) in the middle of it for dominancy testing.  The hole would be
apochromatic, aspheric,multicoated with a special lens hood in typical
Leica fashion.  They will be $189 each but will be backordered for 6
months.  An autofocus model has been rumored to be a future consideration.  

Best regards,

Richard
- --------------------------------
Richard Clompus, OD
West Chester, Pennsylvania, USA