Not an MS thing, that I know of.
I do have a conjunctivitis-like problem with one eye (always the same eye) that flares up from time-to-time, but it was tested and was not an infection.
Some immune diseases (notably lupus) can cause problems with dry eyes - paradoxically it can seem like the eye is runny, because it gets sore.
However, MS is not in the group associated with this.
I’ve been told mine’s not MS, I’ve had full rheumatology screening - twice - on the way to being diagnosed with MS - so can be fairly confident it’s not another immune thing, including lupus.
Nobody has ever diagnosed it. The closest answer I’ve ever got is: “It’s like an allergy”, but nobody has been able to explain to me how anyone can have an allergy in just one eye.
I don’t seem to have had it so much since I stopped work, which is strange, as I worked from home anyway, so my environment hasn’t changed.
I wonder if it had something to do with extended hours on the computer (I still spend a lot of time on the computer, but take a nap in the afternoons, so it’s not continual.)
Or if it was something in particular to do with my work computer, which I had to give back. It was old and pretty clapped out, so might have had a problem with screen brightness, or screen resolution or something.
Apart from switching to a computer I bought myself, and having a nap in the afternoons, I can’t think of anything else I’ve changed that would make a difference to the eye problem.
It hasn’t gone away completely - that eye is always a bit more sensitive. But it hasn’t flared up badly for a long while.