PVD

I had a bout with PVD over the weekend. I had flashing lights in my eyes and more floaters. I was afraid I had a detached retina, so I went to an eye doctor. I had never heard of PVD, but apparently it is quite common in old folks my age. The following quote from a medical web page describes my experiences pretty accurately:

"Posterior Vitreous Detachment (PVD) is a common condition which occurs in about 75 per cent of people over the age of 65. As people get older the vitreous, a jelly-like substance inside the eye changes. The vitreous takes up the space behind the lens and in front of the retina, the light sensitive layer at the back of the eye. It is 99 percent water. The other 1 percent consists of substances which are important in maintaining the shape of the vitreous. The outer part of the vitreous (the cortex) has the highest concentration of collagen. The vitreous is attached to the retina, more strongly in some places than others.

"When a PVD starts, the jelly comes away from the retina. The vitreous changes with age. The central part of the vitreous becomes more liquid and the outer part (cortex) 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."