Retinal detachment requires urgent medical attention.

The symptoms include sudden changes in vision (e.g. blurring), a hole or a cloud of small dots appearing in the field of view (floaters), or flashing lights in the vision.

A few floaters are perfectly normal and the above symptoms can have less serious causes, but if retinal detachment has happened urgent treatment is needed so you need to get a prompt expert diagnosis from a GP or optician.