Posterior vitreous detachment is not painful and it doesn’t cause sight loss, but it can cause symptoms such as floaters (small, dark spots or shapes) and flashing lights. With time the brain learns to ignore these symptoms. Crucially, however, the symptoms of a Posterior Vitreous Detachment are very similar to a different condition called retinal detachment, which is sight threatening. It is important to be examined by an ophthalmologist, or optician, within 24 hours of developing floaters of flashing light symptoms, so that an accurate diagnosis can be made. A retinal detachment requires urgent surgery.