TargetTalk

As I posted earlier , I am new to the sport , shortly after I started from last Sept , I have been using shooting glasses with lens & a cover on my non-aiming eye ; last night , it was the first time I tried using an iris , I shot a total of +/- 100 shots , towards the last 30 shots , I noticed that I have difficulty locating the sight picture , I needed to move my head to find it ; I assume this is a tired neck/head after shooting for that time period , as a result , I closed my non-aiming eye when I reached the top of the target , & then align the rear sight , & then opened it again , I noticed that I was moving my head slightly to acquire the picture , my question is : am I doing this wrongly ? When I do archery , I close my non-aiming eye all the time during aiming & shooting. I don't want to go back to no iris , because it really pumped up the result of my scores !

I am not experienced to answer your question. But I close my non-aiming eye ANYWAY, even though I always use a blinder on my Knobloch. The non shooting eye lens is partially there for safety purposes. If I don't use shooting glasses, I also shoot with the non aiming eye closed.
My personal experience is that opening my non shooting eyes with blinders actually is a hindrance, but others may find it an advantage. However, you must make sure BOTH lenses has the correct prescription, even if you do not plan to open your non shooting eye.

You should keep both eyes open, it helps depth perception, equal pupil size, and balance. Look in the mirror when you close one eye and you'll see the other one squint as well, whilst the pupil opens up.

Fatigue will affect all muscles, including the head, neck and eye muscles. Suggest you don't shoot as much for now, and build up to it.

Rob.

Rob already explains it, also the method to convince yourself of the need of two open eyes: standing free with both feet close together, both eyes open, then one eye closed, then two eyes closed - and look before starting this experiment, where you will possibly fall down later...

In fact the eyes coordinate the balance together with the equilibrium sense in the ears - if you cut off information, you will start to loose balance.

Further more, the iris in the closed eye will open under the lid (yes!) because the lack of light. Both eyes are combined in your brain, so if one iris opens, also the other one also opens a bit automatically - and looses its facility of depth perception. The same applies (a little less) if you use a blind for the left eye with a black surface instead of white or milky transparent. (sorry for my bad english, I always need 1-2 days talking to warm up...)

If you have problems with double visions etc while keeping both eyes open, you only need to block the line between the non-aiming eye and the sights. This can be done by a small blind, as light as possible.

For the reasons noted, both eyes open is optimal. I think that you will find shooting with both eyes open is a bit like your brain accustoming itself to bifocals. It takes some time, but before long your brain will be ignoring the non-dominant eye while shooting. Give it a week or two of regular shooting with both eyes open and see what happens.
Good shooting
Brian