Flashes and Floaters
Posterior Vitreous Detachment (PVD) is a common condition which occurs in about 75% of people over the age of 65. As people get older the vitreous, a jelly-like substance within the eye which takes up the space behind the lens and in front of the retina, the light sensitive layer at the back of the eye, changes. This can cause Posterior Vitreous Detachment. When a PVD starts the jelly comes away from the retina.
Why does the vitreous detach?
The firm jelly-like substance of the vitreous changes with age. It becomes more liquid and peels away from the retina. As it comes away from the retina it can cause the symptoms of posterior vitreous detachment.
Many people are not aware that they have developed PVD but some notice symptoms such as floaters or flashing lights. Floaters can take many forms from little dots, circles, lines, to clouds or cobwebs. Sometimes people experience one large floater, which can be distracting and make things difficult to read.
The flashing lights that occur are also caused by the PVD. As the outer part of the vitreous detaches from the retina it can pull on this light sensitive membrane, especially where the vitreous is attached quite strongly to the retina. The pull of the vitreous in these areas stimulates the retina. This stimulation causes the sensation of flashing lights since the brain interprets all stimulation signals from the retina as light.
Unfortunately at the moment nothing can be done medically for this condition, usually people find that the symptoms calm down after about six months and people do eventually get used to living with the floaters. The brain tends to adapt to the floaters and eventually is able to ignore them, so they then only become a problem in very bright light.
PVD does not in itself cause any permanent loss of vision. Your visual acuity should remain the same that is you will be able to see just as you could before the posterior vitreous detachment started.
The only threat to vision is the chance of a retinal tear leading to a retinal detachment. Sometimes the vitreous is so firmly attached to the surface of the retina that as the jelly collapses it pulls quite strongly on the retina which may lead to the retina tearing which in turn could lead to a retinal detachment. Early intervention may allow treatment of a tear before it becomes a detachment.
Your ophthalmologist (the hospital eye specialist) will give you a thorough examination during your first visit. They will pay special attention to whether or not the retina is in any danger. If it isnt then they may not need to see you again. However if you begin to experience the symptoms warning of a possible retinal detachment, such as increased or definite change in floaters more severe flashing lights or a curtain falling over your vision then another trip to the doctor will be necessary.