I'm currently taking meditation course during which I focus on the sensation of breath in my nostrils for 1 hour, few times a day. It turned out that during my practice I involuntary follow my nostrils with my eyes, which causes tension on forehead.
My instructor recommended to tie a piece of cloth around my eyes to prevent it. I tried it and discovered I could now sit for 1 hour without tension. However, after finishing the session, I discovered that my left eye is out of focus. It only improved slightly during few hours. I didn't feel any pain.
Next morning was already much better, but I still see a subtle difference between my left and right eye.
1. What do you think happened to my eye? Is there a chance of permanent damage?
2. Is it safe to practice in this way if next time I'm more careful to tight the band more loose?
3. Is practice without band safe?
Thanks for your Question
Most likely what you have is called phoria which is a latent squint or misalignment of the eyes that appears when binocular viewing is broken.
People with phoria can complain of headache, eye strain, difficulty in changing focus from near to distance and vice versa and increase sensitivity to light and sometimes intermittent diplopia.
It appears when the person is tired, have illness such as flu, prolong and excessive near work. i don't thing it has to do anything with how tight or loose your band.
I prefer if you visit your eye doctor because sometimes uncorrected refractive errors can cause phoria.