I had double vision and nystagmus together, sigh. Like Herekitty it is what earned me my MS diagnosis.

I'm not sure if this will help since yours is only 1 eye but I cut out a piece of black paper the size of my glasses lens and taped it to one of them. I also used an eye patch but felt the paper on the lens was better although neither one of them looked particularily spiffy.

I hope you get some relief soon.