Floaters are very common and you need not worry unless it has increased in number or you have flashes of light with it and a progressing hazy vision. If you have these additional symptoms,then please have a retinal specialist opinion.High myopia
and old age (posterior vitreous detachment
) can cause them.
Your blind spot
, is it located only in one eye at the same site like a curtain? A floater with a curtain shaped dark area must not be ignored as it could be a retinal detachment
Grey patch in eye may be due to thin sclera or in younger age group vitamin deficiency
We have veins throughout our white part of the eye(sclera), a few of which becomes prominent sometimes due to a reaction against allergy/heat/infection.So no worries about them too.
If you are too concerned about the number of floater get examined at the earliest with an ophthalmologist specialized in Retina.