WHAT ARE FLASHES & FLOATERS AND POSTERIOR VITREOUS DETACHMENT (PVD)?
Floaters are often described as spots / lines / cobwebs and other shapes that one may see floating about in their vision. These are caused by impurities in the vitreous which is a jelly like structure that fills a majority of the ‘space’ within the eyeball. When we are born, the vitreous has a consistency like a firm pot of jelly. It is perfectly clear and is well attached to the inner surface of the retina (the retina is the light sensitive membrane at the back of the eye that acts much like the camera film). Over time however, the vitreous degenerates and becomes more watery in nature as well as forming clumps that float around and cast shadows on the retina, resulting in symptoms of floaters.
In addition, the degenerative process also makes the vitreous shrink in size causing it to pull away from its attachment to the retina. This process is called Posterior Vitreous Detachment (PVD). As the detaching vitreous tugs on the retina via remaining areas of adhesion, it mechanically stimulates the retina which produces a sudden sense of light, giving the symptoms of flashes. These are more visible in dim light conditions and when one moves their eyes from side to side. Not every eye undergoing posterior vitreous detachment experiences symptoms of flashes and floaters.
IS PVD DANGEROUS?
Because PVD is part of the aging process, every eye will undergo PVD at some timepoint with varying degrees of symptoms. However, in up to 10% of people with symptomatic PVD, the detaching vitreous may pull on the retina hard enough to produce a retinal tear. Some of these tears may then lead to a retinal detachment – a blinding condition where the retina comes away from the wall of the eye and requires relatively urgent surgery to repair. As such it is very important to have a thorough examination of the retina through dilated pupils (with drops) for those with symptoms of flashes and floaters. If a retinal tear is found, then retinal laser treatment can be performed urgently in our clinic to prevent it from progressing to a full blown retinal detachment.
TREATMENT OF PERSISTENT FLOATERS?
As mentioned above, symptoms of floaters generally become less bothersome and a majority of people will overlook the intermittent appearance of the few floaters. Rarely, however, they may continue to be very prominent and cause debilitating obscuration of the vision. In this minority of patients, specialised lasers can be used to disperse the vitreous floaters. Complete removal of the vitreous by surgery is also considered in treating these rare cases.
Our doctors at Applecross Eye Clinic can discuss with you further on any concerns you have regarding flashes, floaters and posterior vitreous detachment.
WHAT HAPPENS AFTER A PVD?
The symptoms of flashes will invariably subside when all the vitreous adhesions completely break down. Some may take a longer time than others but it almost always eventually disappears. This is opposite to floaters, however, which generally will remain indefinitely. For the majority, it does become much less noticeable / bothersome over time but never completely disappears. Even if no retinal tears were found in the initial examination, there is still a small risk that retinal tears or retinal detachment can subsequently develop. Symptoms that should not be ignored include;
- Sudden substantial increase in floaters (e.g. sudden shower of numerous spots in the vision). This may indicate a small bleed into the vitreous from a fresh retinal tear.
- A missing part in the peripheral vision (e.g. as though a black opaque curtain is completely blocking part of the vision)
- Significant worsening of vision