Flashes and Floaters

What are floaters and what is a Posterior Vitreous detachment (PVD)?

Floaters describe the symptom of seeing a shadow moving (or floating) across the vision. Sometimes they are described as a dirty cobweb, flies, a ‘hair’ in the vision or a ‘dirty windscreen’.

Floaters are seen when the fibres that make up the "jelly" (vitreous) at the back of the eye start to clump together. When you are a child, the jelly is perfectly clear, allowing you to see through it without any trouble. As you get older these fibres start to clump together, causing floaters.

Normally, the vitreous (ie the jelly in the eye) adheres to certain parts of the retina. The retina is the nerve tissue found at the back (or posterior) part of the eye. It is the part that senses light. 

A posterior vitreous detachment (PVD) is when the vitreous pulls away from the retina. It is most commonly associated with floaters in the vision and flashing lights.

Importantly, when the vitreous pulls on the retina, you may notice flashing lights. These are usually only for a split second, and they often occur in the outside part of your vision in the affected eye. Flashes are most often noticed in the evening and can be quite disconcerting and annoying. Not everybody experiences them. 

Retinal tears can occur if the vitreous pulls too hard on the retina as it separates from it. Retinal detachment is an uncommon complication of this process.