Posterior Vitreous Detachment (PVD) is an eye condition that occurs in about three quarters of individuals over 65 years of age. The vitreous - a clear jelly-like substance in the eye - changes as people age. This may result in Posterior Vitreous Detachment.
The Vitreous: Its Composition
The vitreous is comprised of 99 per cent water, and 1 per cent substances active in maintaining its shape. The vitreous is situated in front of the retina (a layer which is sensitive to light at the back of the eye) and just behind the lens. The vitreous attaches itself to the retina in several places. It is 99 per cent water, with the remainder of the substance supporting its shape. The outer part of the vitreous - called the cortex – contains collagen. The vitreous is attached to the retina, more strongly in some places than others. When a PVD starts, the jelly -like substance begins to come away from the retina.
The Process of Vitreous Detachment
The vitreous changes as the individual ages. Its center becomes more liquid over time, and the cortex peels away from the attachment points of the retina. This process can create the symptoms of PVD.
Signs and Symptoms of PVD
The symptoms of PVD may be slight. Individuals may discover the presence of flashing lights or floaters across their visual fields.
The appearance of flashes occur as the retina pulls away from this light-sensitive membrane, especially where the vitreous and retina are strongly attached. This pulling effect of the vitreous stimulates the retina into producing the appearance of flashing lights. The brain creates the apparent flashes of light as this is how retinal stimulation is interpreted.
Floaters can appear in many ways, superimposing themselves over the visual field. These can range from small dots to spider-shapes, lines or patterns. Light entering the eye casts a shadow on the photoreceptors, and therefore, the person sees a floater. A large floater can impair vision significantly.
Management of PVD
There is no cure for this condition. Many people who experience PVD discover that the symptoms subside after a few months. Some people also get used to the presence of floaters. Sometimes, the brain is able to adapt to them, so that they are only noticeable in strong light conditions.
Moving the eye around can produce currents in the vitreous that can occasionally move the floater out of the visual field. Posterior vitreous detachment does not result in permanent loss of vision. Visual acuity remains the same, although the flashes and floaters can be a hindrance to seeing well.
If there is an increase in floaters or flashes in one eye, or a sudden appearance of a dark cloud over the visual field, an appointment with an ophthalmologist is necessary, as these symptoms can indicate the presence of a retinal tear which in turn could lead to retinal detachment. However, it is unusual for PVD to develop into retinal tears or detachment. Most individuals with floaters or flashes discover that they become progressively less problematic over time.
Reference: The Eye Book: A Complete Guide to Eye Disorders and Health, G H Cassell MD, M D Billig, OD, H G Randall MD. Publisher: The John Hopkins University Press. (2000)
Iona K Lister - Based in the United Kingdom, I have written four published books and hundreds of articles. Subjects cover a wide range – including ...
