Hi, may I know your glass prescription?
Since you said, dilated fundus examination was done by a retina specialist, I think it can be liquifaction of vitreous gel, which you need not be worried of.
Try to avoid focussing on it a lot.
Sometimes visual hallucinations can be there, as u mentioned you are on anti depressants.
Next Steps
Meet a neurologist if symptoms worsen
Health Tips
Have sound sleep.