
Originally Posted by
grant hutchison
Actually, everyone gets posterior vitreous detachment at some time, late 50s onwards. Your vitreous becomes less flexible and shrinks slightly with age, and eventually lifts off the retina. Most people never notice this happening, but in a small proportion the vitreous sticks to the retina and then pops free, producing a shower of cellular debris (floaters) and an interesting display of lights (flashers). If you're very short-sighted your retina is a little more fragile around the edges, and you're more likely to sustain damage, which can include a haemorrhage into the vitreous, a tear in the retina and (if no action is taken) a retinal detachment and permanent vision loss in part of the visual field. So sudden onset of floaters and flashers is always a cue to get yourself to an optometrist as promptly as you can, because the retinal detachment can be prevented. (Forgive my bold, folks, but it's something that everyone of a certain age should know, particularly if they're short-sighted.)
As an extremely short-sighted person, I'm a sitting duck for a complicated vitreous detachment, and sure enough I've had one in each eye.
I got very lucky on both occasions. The first occurred five hours before we were due to fly off to spend two weeks in a wilderness lodge in Canada; the second, last year, when we would have been on a small ship in the Aleutians were it not for the Current Unpleasantness.
The first involved a vitreous haemorrhage, which took the form of a long black octopus tentacle extending itself from the lateral side of my field of vision suddenly, and waving around dramatically--so instead of flying to Canada I had laser surgery to tack down the edges of the retinal tear. The second was a shower of floaters and an arc of blue-white flashing in my peripheral vision, with no tear.
Now, three years after the first and one year after the second, I still have arcs of blue lights in my peripheral vision when I move my eyes from side to side in a darkened room. Your brain certainly does become used to the floaters, and although I have a mass of them in both eyes, they're not usually bothersome. They're more noticeable in bright light, when the pupils constrict, because that projects a cleaner shadow on to the retina--so I wear sunglasses outdoors a lot. And they have a tendency to show up if I'm sitting in a dark room looking at a bright screen.
(The only treatment for the floaters is a vitrectomy, which is to remove the vitreous from the affected eye and replace it with saline solution. Not without hazard to one's vision, which is why it's generally considered "unreasonable"--the cure has the potential to be worse than the disease, in almost all cases.)
Grant Hutchison