The vitreous in the eye gets removed and replaced by saline. Right?
Does the body then, over time, replace the saline with new vitreous?
Actually, saline is not necessarily used. There are a number of vitreous substitutes that can be employed.
Look here.
Missed the edit window.
Aqueous humor, from the front (anterior) chamber of the eye can also be used as the vitreous substitute.
Assuming saline was used – does the eye eventually replace it?
At the risk of sounding evasive, it depends on how what you mean by ‘replace’. As I understand it (not well), for example, all sorts of proteins quickly diffuse into the saline and so change its composition. Is that replacement? At the end of the day, it’s no longer saline in the posterior chamber, it’s a protein-rich fluid, the ions of which presumably include more than Na[sup]+[/sup] and Cl[sup]-[/sup] after some time.
The eye does not however regenerate vitreous. So you are forevermore without the more solid support for the retina. Which is itself a mixed blessing. Many vitrectomies are performed because the vitreous has detached and is in the process of causing a retinal detachment. In this case it is typical to replace the vitreous with either silicone oil or perfluoropropane to support the retina. Silicone oil needs removing eventually, the gas tends to very slowly adsorb and is replaced by fluid. But there are lots of other reasons for a vitrectomy.
I had a vitrectomy three years ago. The silicone oil has not been removed and likely never will be. This is because the surgeon says there is at least a 30% chance that removing it will lead to a new retinal detachment. Although the vision in that eye is not good it would be enought that if anything happened to the other eye, I would still be able to walk down the street (I have tried this) although not read unless there was very large print.
I’ve had two vitrectomies, same eye. It’s been a few years so perhaps my memory has faded, but I thought I was told the vitreous was replaced with a gas. That being the case, I was not permitted to expose myself to any significant changes in altitude. Certainly no airline travel.
They seemed to be worried that the oil could eventually lead to damage to the cornea or lens capsule. It can lead to some pretty nasty problems if it gets where it shouldn’t be. Cataract lens replacements and oil are not always a happy pair. I was somewhat surprised - silicone is pretty benign in the body. I’m not surprised there are surgeons that are leaving it in. Getting it out isn’t fun. Restrictions on flying are whilst there is any chance there is gas remaining in the eye. For rather obvious reasons they are not keen on a bubble of gas cheerfully expanding in your eye as the pressure drops.
There are a whole heap of nasty surprises and complications possible. A friend of mine managed to get caught by just about every one of them as she progressed. I learnt a lot helping her.
Okay, I didn’t tell the whole story. First they did the vitrectomy and put in a gas bubble. Not only no flying, but I was supposed to lie face down (or sit with my head facing down for 15-20 hours every day for three weeks. I rented a special sleeping support that lay on my bed and held my whole body except a nose hole about 2 inches off the mattress. It was incredibly uncomfortable. I also rented a device that allowed to sit with my face down and had a mirror arrangement that allowed my to watch TV or, theoretically, to read, although I could never make the latter work. Well, I didn’t follow the instructions precisely. Maybe if he had given me a sedative or sleeping pills, but he didn’t. Anyway, three weeks later the retina had separated again and he operated a second time, this time putting the oil drop in instead. Although I was supposed to sleep head down for a couple days, the other regime wasn’t necessary. He does examine me regularly (now only once a year) to make sure the oil has not “emulsified”. If it does, he will have to remove. But for the time being, he would rather not. It is, as always, up to me and I have chosen to follow his advice. He very carefully explains the choices and then leaves it up to me.
A friend of mine had vitrectomy a few months ago. The was a huge hole in the back of his eye and he was essentially blind on that side. They did the thing and injected a bubble of some kind of goop or glue or something. This stuff would, in three days settle against the hole and patch it. He said the procedure itself wasn’t diddly-squat. But for three days after it was done he had to lay on his stomach so the bubble would float up against the hole. He was allowed to get up and go to the bathroom as long as he kept looking directly down.
Don’t know what they replaced the vitreous with. Maybe they just put it back after they were done.
I see several posters had a similar story. Maybe I could have read the whole thread before jumping in with my own anecdote.
My mother had this done recently, and my understanding with the ‘gas bubble’ version is that the gas eventually is absorbed into the body, and the body eventually refills the eye with fluid as that happens. It’s not the same as the vitreous humour, but it works.