eye drops == saline == rewetting drops ?
November 3, 2008 1:52 PM Subscribe
What's the actual difference between saline, eye drops, and rewetting drops? They all seem pretty interchangeable to me.
Eye drops can contain all sorts of stuff, depending on what they're for, although the base constituent is generally saline.
posted by le morte de bea arthur at 2:10 PM on November 3, 2008
posted by le morte de bea arthur at 2:10 PM on November 3, 2008
They're all eye drops, and they're all 99% saline. They differ in what else, if anything, they have. Usually an anti-redness and/or anaesthetic.
posted by rokusan at 2:41 PM on November 3, 2008
posted by rokusan at 2:41 PM on November 3, 2008
Best answer: From this article:
First-generation rewetting drops were basically saline-type solutions that temporarily added moisture to the lens to rehydrate it and decrease dryness symptoms. However, after 15 to 30 minutes the symptoms would return, sometimes worse than before drop usage.
I remember there being some sort of controversy a decade ago or so because many companies' rewetting drops were just their saline repackaged at a much higher price, but now I can't find any information about that.
Anyhow, now most rewetting drops are more complicated. As le morte says, eye drops in general can contain any number of ingredients.
posted by nat at 2:42 PM on November 3, 2008
First-generation rewetting drops were basically saline-type solutions that temporarily added moisture to the lens to rehydrate it and decrease dryness symptoms. However, after 15 to 30 minutes the symptoms would return, sometimes worse than before drop usage.
I remember there being some sort of controversy a decade ago or so because many companies' rewetting drops were just their saline repackaged at a much higher price, but now I can't find any information about that.
Anyhow, now most rewetting drops are more complicated. As le morte says, eye drops in general can contain any number of ingredients.
posted by nat at 2:42 PM on November 3, 2008
Best answer: Using pure saline routinely is not a good idea. One of the functions of tears is to act as a lubricant for the eyeball and socket, and saline is not good at that.
Proper "artificial tears" will also include some sort of sliming agent. There are a number of different ones approved for this use by the FDA and different brands use different combinations. I used to use Visine Tears, which contains glycerine, hypromellose, and polyethylene glycol. Now I use Murine Tears, which contains polyvinyl alcohol and povidone. The main reason I switched was that the Murine costs half as much and works just as well.
Those extra ingredients are there to make the stuff a good lubricant. They don't "get the redness out" and they're not anesthetic. They're also not antihistamine. It's not a good idea to use "get the redness out" drops continuously for long periods of time because you can get rebound irritation if you ever stop. (That's also the case with anti-histamine eye drops; they're for occasional use only.)
On the other hand, extended use of pure saline can lead to the eye socket becoming irritated from friction, which really hurts a lot.
posted by Class Goat at 3:56 PM on November 3, 2008
Proper "artificial tears" will also include some sort of sliming agent. There are a number of different ones approved for this use by the FDA and different brands use different combinations. I used to use Visine Tears, which contains glycerine, hypromellose, and polyethylene glycol. Now I use Murine Tears, which contains polyvinyl alcohol and povidone. The main reason I switched was that the Murine costs half as much and works just as well.
Those extra ingredients are there to make the stuff a good lubricant. They don't "get the redness out" and they're not anesthetic. They're also not antihistamine. It's not a good idea to use "get the redness out" drops continuously for long periods of time because you can get rebound irritation if you ever stop. (That's also the case with anti-histamine eye drops; they're for occasional use only.)
On the other hand, extended use of pure saline can lead to the eye socket becoming irritated from friction, which really hurts a lot.
posted by Class Goat at 3:56 PM on November 3, 2008
Many, if not most eye drops contain additional ingredients. Visine contains tetrahydrozoline, which causes constriction of blood vessels. Not just saline.
Rewetting drops usually refers to rewetting of contact lenses. If you have dry eyes and don't wear contacts, you would use regular eye drops.
On the flip side, you aren't supposed to use regular eye drops or lubricant with contacts, either. They may contain ingredients that don't jive with contacts.
posted by fructose at 4:04 PM on November 3, 2008
Rewetting drops usually refers to rewetting of contact lenses. If you have dry eyes and don't wear contacts, you would use regular eye drops.
On the flip side, you aren't supposed to use regular eye drops or lubricant with contacts, either. They may contain ingredients that don't jive with contacts.
posted by fructose at 4:04 PM on November 3, 2008
I use Systane Lubricant Eye Drops due to recurrent corneal erosions. These drops contain polyethylene glycol and propylene glycol, and are an incredible relief if you have any problems like these. The main difference is the lubrication and some viscosity.
posted by sonic meat machine at 4:17 PM on November 3, 2008
posted by sonic meat machine at 4:17 PM on November 3, 2008
I once used rewetting drops as a contact solution substitute in a pinch to store my contacts over night. Eyes burned like hell when I put them back in the next morning. Would not recommend it.
posted by toomuchpete at 4:25 PM on November 3, 2008
posted by toomuchpete at 4:25 PM on November 3, 2008
Visine contains tetrahydrozoline, which causes constriction of blood vessels.
Some Visine products contain tetrahydrozoline. Some do not. Read the package labels.
Anything labeled "artificial tears" or "lubricant eye drops" will have no active ingredients except for sliming agents. That's the case for "Visine Tears" and "Murine Tears".
posted by Class Goat at 4:38 PM on November 3, 2008
Some Visine products contain tetrahydrozoline. Some do not. Read the package labels.
Anything labeled "artificial tears" or "lubricant eye drops" will have no active ingredients except for sliming agents. That's the case for "Visine Tears" and "Murine Tears".
posted by Class Goat at 4:38 PM on November 3, 2008
I have Bausch & Lomb Advanced Eye Relief™ Dry Eye Rejuvenation Lubricant Eye Drops (Active Ingredients: Glycerin (0.3%) - Lubricant and Propylene glycol (1.0%) - Lubricant)) and Allergan Refresh Redness Relief Lubricant Eye Drops (Active Ingredients: Phenylephrine HCl (0.12%) (Redness Reliever), and Polyvinyl Alcohol (1.4%) (Eye Lubricant)) on my desk now. I have eye irritation due to a myriad of allergies, and no contacts, and both work well enough to alleviate the itch and irritation (sorry the second link is a shopping site - it was the first I could find with ingredients listed).
As above - read the fine print.
posted by filthy light thief at 4:42 PM on November 3, 2008
As above - read the fine print.
posted by filthy light thief at 4:42 PM on November 3, 2008
Phenylephrine is notorious for causing symptom rebound after steady use. It also used to be used as a nasal decongestant (and you can still buy it) and it's notorious for causing what amounts to addiction in its users.
If they work for you, you're much better off using eye drops that just contain lubricant.
posted by Class Goat at 7:00 PM on November 3, 2008
If they work for you, you're much better off using eye drops that just contain lubricant.
posted by Class Goat at 7:00 PM on November 3, 2008
This thread is closed to new comments.
posted by substrate at 2:00 PM on November 3, 2008