What Causes Dark Spots Behind The Eye?

Hi,my name is Gary, I have M.S. and and I take Fingolomoid a drug given to remitting relapse m.s patients.Possible side effects can be fluid build up and swelling at the back of eye.I went to a ophhtalmologist "planned appointment" and luckily had none of the above but did see dark shadows or spots behind left eye.Was very vague what they could be and have to go back in 3 months time for follow up. I would be grateful for any possible answers.