~About contacts blocking oxygen to corneas~

  1. Isn’t thislack of oxygen bad for your eye long term? What are the ST and LT effects of this oxygen deprivation?

  2. If it’s bad, isn’t it, then, a good idea to just wear contacts occasionally (for sports or night driving), if you have good enough vision to get around without them? (By occasionally I mean 3 times a week for 10 hours at a time)

I have heard in other threads that wearing contacts occasionally is bad? How so?

  1. Also, does closing your eyes at night block oxygen in the same way as wearing contacts?

I could really use the straight dope on this, thanks.

Wearing hard contacts to sleep can scratch your cornea, doesn’t make you go blind but you have to not open your eyes for a few days for it to heal. Soft contacts are safe as far as I know.

Never heard of only wearing them occasionlly being bad, or been told by eye doctor person - at least for soft ones.

I don’t think closing your eyes is what blocks oxygen, it’s the not moving them. REM sleep isn’t just about dreaming, it keeps the corena oxygenated as well.

Last I heard they were damn close to contacts you could wear for a week at a time, I’m assuming they’d be soft. Most problems probably come from the hard ones - so as long as you have soft contacts you should be in the clear.

What oxygen are you blocking? Humans supply blood to the body via the circulatory system, not through diffusion from the atmosphere. After all, you’re not worried about the skin underneath your fingernails being covered, right?

Actually, the cornea does get its oxygen supply from the air, being as there are no blood vessels into the cornea. (If there were, you would have vision problems.)

Soft contacts are gas permeable. They make gas-permeable hard contacts, too, now. I don’t believe they stilll make the old-fasioned hard contacts that are not, as no one should wear them.
Lack of oxygen to the cornea can lead to cornea edema, not a scratching problem.

My mother has soft contacts that can be worn for up to a month at a time.

:smack:

Man, don’t I feel stupid. In GQ, no less. Excuse me while I attempt to remove my foot from my mouth.

Still don’t want to wear the hard ones to bed, gas permeable or not they can still scratch up your cornea.

Hi. I changed the type of contacts I wear awhile ago so I did a lot of reading on the subject.

Soft contact lenses do allow enough oxygen to get to the eye, but not as much as RGP (rigid gas-permeable) lenses. Either way, daily wear really isn’t a risk. A long day in contacts can make one’s eyes feel tired, but it’s probably due more to dryness (especially for soft contacts, which are mostly water) than anything else. Neither should be worn to bed not only because of the risk of oxygen deprivation but moreso because of the risk of infection.

As for any ill effects of occasional wear . . . the only instance I can think of would be for hard lenses. Hard lenses don’t become comfortable until the cornea has literally been reshaped by them. Wearing hard contacts only occasionally wouldn’t force the cornea to hold its new shape, and wearing them would be more painful. Other than that, as long as you keep them clean and store them properly, anything from occasional to daily wear should be fine.

Thank you so far.

By the way, my question was in relation to 2-week soft contacts.

So, no complications from only wearing them occasionally? I would think not, but have heard otherwise and needed confirmation either way.

Nope, I can’t see any problem with that. As long as you clean them and wear them for proper amounts of time and everything, it doesn’t really matter how often you wear them. What DID you hear about wearing them occasionally, anyway? It must be something horrible to make you worry so much.

Am I worrying, or am I just asking?

herman_and_bill said this to me in another recent thread:

“get used to them, believe me and everyone else who has been thru this you won’t want them just for occasional wear.”

http://boards.straightdope.com/sdmb/showthread.php?s=&threadid=182655&highlight=contacts

He never answered me, so I asked here.

If you wear contacts you will become acclimated to them. I have no factual answers to the oxygen questions, and I think Barbitu8 gave a good rundown.
When I started contacts, for the first few weeks I much preffered to wear glasses, but as I got used to them I only wear glasses in the evenings before bed.
I don’t know of any ill effects from wearing them only occassionaly but why not wear them all the time?

He probably meant that you will enjoy having full sight without having to wear glasses so much that you won’t want to wear them only occasionally.

As long as you stick within the limits your optician gives you then you’ll be fine. I have monthly disposable soft lenses, and i can wear them for up to 14 hours a day.

Do be careful not to exceed these limits though. I overwore some contacts because i couldn’t afford any new ones for quite a while once and the lack of oxygen to my eye made blood vessels in my eye grow abnormally or something. I wasn’t allowed to wear contacts for 8 months afterwards, and apparently the damage caused will never properly heal. It hasn’t affected my sight, but could have done if it had gone on longer.

I think that the technology has changed a bit over the past few years. My mum wore soft contacts for 3 years but had problems with them as they were not sufficiently gas permeable. My friends who wear soft contacts now say that that is no longer a problem, but that you still can’t sleep in them because they dehydrate and stick to your eye.

One of them tried this and woke up with the contact torn in two pieces and stuck to his eye’s surface and him in considerable pain.

I myself wear hard gas permeable contacts. When I got them I was told that they were healthier for the eye than soft contacts and that they only hurt more initially because any tissue in the body responds more to hard foreign objects. I have been to sleep in them with no problems.

I went to the docs office, only to find that the doctor was not there. They broke the appt. But, there was this guy there I have talked to before that seemed knowledgable. I kept forgetting to ask if he was a doctor, but he gave professional-type advice, just as the doc would in the patient room, looking at the file, ect. He said with confidence that the redness on both eyes was from drying out and gave me rewetting eyedrops and said that will probably take care of it. We’ll see.

mooka, it’s your story that is the reason I asked this question and why I will only wear them daily if I have to. Thanks for affirming my suspicion. I’m sure the contacts now-a-days are better, but until I see proof, I will still be wary of wearing contacts so much.

Fuel, YMMV of course but I don’t think you really need to worry, because the technology has indeed improved considerably in recent years.

When I first got contacts over 10 years ago, I had soft lenses that I wore up to a week at a time (i.e., I slept in them as well). I had to stop wearing them because I began developing micro-cysts on my corneas, which the opthamologist said was a consequence of insufficient oxygen reaching my corneas. I then switched to rigid gas-permeable lenses for about three years. That solved the micro-cyst problem, but unlike others in this thread I hated my gas permeables with a passion - the slightest fleck of dust underneath a lens made my feel as though I was being stabbed in the eye, and the lenses had a tendency to pop out if I rubbed around my eye at all. When I couldn’t take it any more, I begged the doc to switch me back to soft lenses, which she did - apparently the lenses are thinner and made of newer materials that allow oxygen to pass through more effectively. Just to make sure that I don’t develop microcysts again I don’t wear my lenses over night, but I can tell you that I haven’t had a single problem in the four years since I switched back. (BTW, I wear Acuvue II lenses, which you throw away after 2 weeks of wear.)

Personally I also much prefer to wear my contacts rather than glasses because I can see better with them. The only time I don’t wear them during the day is if I know I’m going to do some graphics work, or anything else that will make me stare at a monitor for hours, because my eyes will get dry and irritated. The cure for that is simply re-wetting drops if the lenses are still in, or else Visine once they are out.

That you should not do. Gas permeable rigid contacts have to be removed at least every night before going to bed. Removing them and cleaning them in the middle of the day is not a bad idea either.

These are foreign objects that you are sticking on your corneas. Do so with great care. Don’t get careless.

I wore the gas permeable rigids before a RK in 1991. My vision is greatly improved, but I still need a slight correction in each eye, so I wear regular glasses now. Contacts are a hassle with the cleaning every night and when dust particles get under them, they do hurt. Not a pleasant sensation while driving. In addition, I found them a hassle to remove before swimming. I never could get the hang of winking them out. I had to use two hands and push them out. Could be the way my eyeball is shaped. The only real advantage I found to them is in playing tennis, racketball, and basketball. They’re good when playing sports or when it is raining out while running. Or if the humidity is high and regular glasses fog up. Hmmmm. Maybe I’ll go back to contacts. :slight_smile: