I close my left eye all the time. It seems to take extra muscle power to hold it open. My vision is worse in my left eye, but my glasses are adjusted to correct the difference and it still happens. I do have lazy eyes (both of them), and after my stroke I had ptosis, but the shutting of my left eye has been since childhood. The next time you get new glasses, let the doctor know.
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And in the end, the love you take is equal to the love you make.