Flashes and floaters: when to worry

In this video, renowned ophthalmologist Professor Paulo Eduardo Stanga of The Retina Clinic London explains what flashes and floaters are, why they occur and when they may need urgent medical attention.

Floaters may appear as small dots, lines, cobwebs or shapes moving across your vision, while flashes can look like brief flickers, streaks or sparks of light. Although these symptoms can be caused by common age-related changes inside the eye, their sudden onset may indicate a posterior vitreous detachment.

A posterior vitreous detachment happens when the gel-like substance inside the eye begins to separate from the retina. In some cases, this movement can pull on the retina and cause a retinal tear. If left untreated, a retinal tear may develop into a retinal detachment, which can permanently affect sight.