This is a great article which speaks about the use of probiotics and the effects of them on the eyes. I have found this to be true for the last two decades (under the appropriate circumstances of course) and I also use them (in a specific manner) topically in the eye when there is infection with tremendously positive results. I thought this would be a great article to share with everyone: 

https://www.eyeworld.org/perspectives-probiotics 

Dr. M