Relationship Between Water Content and Oxygen Permeability

Ragnarox · #1 (**permalink**) 12-12-2007, 05:05 PM

I read that 1-Day Acuvue contacts have a high oxygen permeability because they also have a high water content. I didn't realize the two were connected. Does it always follow that the more water in the contact lens, the better the oxygen permeability, or is it--like most things in life--more complicated than that?

Ragnarox · #2 (**permalink**) 12-20-2007, 10:23 AM

Okay, I just read something that stated that the more water content in a contact lens, the better the oxygen permeability. Then in went on to say that the opposite is true for silicone hydrogel contacts. I'm so confused!

nicholas · #3 (**permalink**) 12-20-2007, 03:22 PM

Although it's generally true, I don't think higher water content always equals higher Dk with hydrogels. For the most part it's true though. With silicone hydrogels, the silicone is responsible for the oxygen permeability, and silicone is hydrophobic (water-repelling). Silicone hydrogels have lower water contents but can have many times the Dk of traditional hydrogel materials. It's really apples and oranges, that's why it's confusing.

Ragnarox · #4 (**permalink**) 12-20-2007, 05:14 PM

Thanks for answering so quickly. You sound pretty smart. If you don't mind me asking, are you an eye doctor?

nicholas · #5 (**permalink**) 12-24-2007, 01:13 PM

Ha ha, no I'm not. I just know a little about this stuff. Thanks for the question though.

Ragnarox · #6 (**permalink**) 10-21-2009, 05:45 PM

Quote:

Originally Posted by nicholas

Ha ha, no I'm not. I just know a little about this stuff. Thanks for the question though.

Well, I guess you had me fooled. Go ahead and see if you can fool anyone else on Lens 101.

Knotlob · #7 (**permalink**) 11-22-2009, 07:04 AM

Take a look at this link:

http://www.optometric.com/article.aspx?article=101727

It discusses the evolution of silicone hydrogel lenses and includes some graphs showing Water Content versus Lens Stiffness versus Oxygen Permeability (dK value).

Silicone Hydrogel lenses are generally different to conventional lens materials but there are variations amongst the individual silicone hydrogel materials.

knotlob

SandiStix · #8 (**permalink**) 11-23-2009, 10:07 AM

Quote:

Originally Posted by Knotlob

Take a look at this link:

http://www.optometric.com/article.aspx?article=101727

It discusses the evolution of silicone hydrogel lenses and includes some graphs showing Water Content versus Lens Stiffness versus Oxygen Permeability (dK value).

Silicone Hydrogel lenses are generally different to conventional lens materials but there are variations amongst the individual silicone hydrogel materials.

knotlob

Thanks for the link, Knotlob. I checked it out and part of the article says "In a slightly modified molecule, a polar group is added without changing the trimethyl structure." This isn't light reading, folks. There's a lot of scientific gobbledygook here.

Maybe you can help me with just one thing, Knotlob. What is "modulus"? I saw it many times in the article, and it sounds like something important, but it never defines this word. Maybe you can explain it.

Thanks.

Knotlob · #9 (**permalink**) 11-23-2009, 11:08 AM

Quote:

Originally Posted by SandiStix

Thanks for the link, Knotlob. I checked it out and part of the article says "In a slightly modified molecule, a polar group is added without changing the trimethyl structure." This isn't light reading, folks. There's a lot of scientific gobbledygook here.

Maybe you can help me with just one thing, Knotlob. What is "modulus"? I saw it many times in the article, and it sounds like something important, but it never defines this word. Maybe you can explain it.

Thanks.

I think modulus in this case is probably referring to Modulus of Elasticity or some similar property, but I read it as the relative stiffness/flexibility of the lens.

knotlob

Ragnarox · #10 (**permalink**) 11-23-2009, 12:43 PM

Quote:

Originally Posted by Knotlob

I think modulus in this case is probably referring to Modulus of Elasticity or some similar property, but I read it as the relative stiffness/flexibility of the lens.

knotlob

Hi Knotlob. Let me see if I understand this modulus thing. If a contact lens has a "high modulus" that means it's stiff right? Why not just say "low flexibility" or something simpler? I can understand what SandiStix meant my "scientific gobbledygook." Have you ever heard of a "spherical inertial sequential pylon destabilizer?" It's also known as a "bowling ball." Can we just say what we mean, people?

Knotlob · #11 (**permalink**) 11-23-2009, 03:39 PM

Quote:

Originally Posted by Ragnarox

Hi Knotlob. Let me see if I understand this modulus thing. If a contact lens has a "high modulus" that means it's stiff right? Why not just say "low flexibility" or something simpler? I can understand what SandiStix meant my "scientific gobbledygook." Have you ever heard of a "spherical inertial sequential pylon destabilizer?" It's also known as a "bowling ball." Can we just say what we mean, people?

I agree entirely with your sentiments Ragnarox. However, I merely provided a link to the article - I did not write it! Plain words are always best, but some professions (especially the legal ones) seem to like to hide behind their own particular vocabulary/jargon).

knotlob

Ragnarox · #12 (**permalink**) 11-23-2009, 04:10 PM

Quote:

Originally Posted by Knotlob

I agree entirely with your sentiments Ragnarox. However, I merely provided a link to the article - I did not write it! Plain words are always best, but some professions (especially the legal ones) seem to like to hide behind their own particular vocabulary/jargon).

knotlob

I'm sorry about that, Knotlob. When I said "Why not just say 'low flexibility' or something simpler?" I guess I was asking the author of the article you put a link to. I can see how you could have misunderstood me. That's the trouble with text. Without voice inflection and body language, it's so easy to be misunderstood. I hope you won't let my carelessness keep you from contributing any more posts to Lens 101. I've enjoyed reading what you've posted so far.

Knotlob · #13 (**permalink**) 11-23-2009, 04:17 PM

Quote:

Originally Posted by Ragnarox

I'm sorry about that, Knotlob. When I said "Why not just say 'low flexibility' or something simpler?" I guess I was asking the author of the article you put a link to. I can see how you could have misunderstood me. That's the trouble with text. Without voice inflection and body language, it's so easy to be misunderstood. I hope you won't let my carelessness keep you from contributing any more posts to Lens 101. I've enjoyed reading what you've posted so far.

Hi Ragnarox

No offence taken. I agree that Text/email is difficult without facial & voice nuances.

I think I also need to be careful how I write my texts as I see how they can be misinterpreted also (re the Bausch & Lomb Hilafilcon B) which you queried

knotlob

BettyBoop · #14 (**permalink**) 11-23-2009, 05:17 PM

Wow. This thread has taken an interesting turn. This could have turned into a really nasty flame war that would have to be deleted, but the two people involved displayed a lot of maturity.

Me, I will quite often write a post, revise it, read it again, and revise it again. Sometimes I revise my post four or five times until I'm sure it's just right . . . and sometimes I still accidentally offend someone.

Like I said, you two handled this misunderstanding beautifully.

Ragnarox · #15 (**permalink**) 07-28-2010, 01:09 PM

Quote:

Originally Posted by BettyBoop

Wow. This thread has taken an interesting turn. This could have turned into a really nasty flame war that would have to be deleted, but the two people involved displayed a lot of maturity.

Me, I will quite often write a post, revise it, read it again, and revise it again. Sometimes I revise my post four or five times until I'm sure it's just right . . . and sometimes I still accidentally offend someone.

Like I said, you two handled this misunderstanding beautifully.

Thanks for saying so, BettyBoop. Knotlob has provided a lot of answers to some hard questions here on Lens 101, and in reading those answers I've come to highly respect him. I was hoping I didn't offend him with my less than careful choice of words.

It's all good though.

SandiStix · #16 (**permalink**) 09-08-2010, 04:22 PM

Quote:

Originally Posted by Knotlob

I think modulus in this case is probably referring to Modulus of Elasticity or some similar property, but I read it as the relative stiffness/flexibility of the lens.

knotlob

Thanks for explaining modulus, knotlob. I think you've probably done it two or three times by now in different threads.

Eyeofharmony · #17 (**permalink**) 09-24-2010, 11:02 AM

Quote:

Originally Posted by nicholas

Although it's generally true, I don't think higher water content always equals higher Dk with hydrogels. For the most part it's true though. With silicone hydrogels, the silicone is responsible for the oxygen permeability, and silicone is hydrophobic (water-repelling).

I have a friend who is hydrophobic. It made things interesting when it came time to be baptized . . .

Ordersixtysix · #18 (**permalink**) 12-16-2010, 02:58 PM

Quote:

Originally Posted by Ragnarox

Okay, I just read something that stated that the more water content in a contact lens, the better the oxygen permeability. Then in went on to say that the opposite is true for silicone hydrogel contacts. I'm so confused!

Hey, you know what would be perfect here? A picture of C3PO's head on a battle droid's body saying "I'm so confused."

So let's go to Google . . . type in "C3PO so confused." (Tap, tap, tap, tap.)

Okay, lots of Star Wars pictures, some even feature Threepio.

Hey, look at that. Fans wearing that Princess Leia slave girl costume. Is that home made . . . ?

Okay, focus. Threepio as battle droid . . . Next page . . . . Next page . . . Blast it, Biggs, where are they?

Huh. None. There are no pictures on the Internet with Threepio's head on a battle droid's body.

Google, you have failed me for the last time . . .

BettyBoop · #19 (**permalink**) 01-03-2011, 05:46 PM

Quote:

Originally Posted by Ordersixtysix

Hey, you know what would be perfect here? A picture of C3PO's head on a battle droid's body saying "I'm so confused."

So let's go to Google . . . type in "C3PO so confused." (Tap, tap, tap, tap.)

Okay, lots of Star Wars pictures, some even feature Threepio.

Hey, look at that. Fans wearing that Princess Leia slave girl costume. Is that home made . . . ?

Okay, focus. Threepio as battle droid . . . Next page . . . . Next page . . . Blast it, Biggs, where are they?

Huh. None. There are no pictures on the Internet with Threepio's head on a battle droid's body.

Google, you have failed me for the last time . . .

You're such a nerd, Ordersixtysix.

You and I are going to get along just fine . . .

Ordersixtysix · #20 (**permalink**) 01-25-2011, 03:49 PM

Quote:

Originally Posted by BettyBoop

You're such a nerd, Ordersixtysix.

You and I are going to get along just fine . . .

Yeah, I kinda geeked out on you didn't I? At least I got distracted by the Princess Lieia costume picture.

Or does that make me even more a fanboy?

SandiStix · #21 (**permalink**) 01-31-2011, 02:47 PM

Quote:

Originally Posted by Ordersixtysix

Yeah, I kinda geeked out on you didn't I? At least I got distracted by the Princess Lieia costume picture.

Or does that make me even more a fanboy?

Hey, isn't that Stan Lee, creator of Spider-Man?

The one with the mustache, I mean.

jamlin · #22 (**permalink**) 02-23-2011, 10:21 PM

Wow! Amaaaaaazing!

Kyleden · #23 (**permalink**) 02-24-2011, 11:23 AM

Quote:

Originally Posted by Ordersixtysix

Okay, focus. Threepio as battle droid . . . Next page . . . . Next page . . . Blast it, Biggs, where are they?

I don't want to get off on a tangent, but I have recently realized how often the word "blast" is used in Star Wars.

"Its markings match the description of a ship that blasted its way out of Mos Eisley."

"You're fortunate he doesn't blast you into a million pieces right here!"

"Open the blast doors!"

"Find the controls to extend the bridge!"
"I think I just blasted `em."

"With the blast shield down I can't even see, how am I supposed to fight?"

"Blast it Biggs, where are you?"

And so on. Did I miss any? I'm sure I did.

RayBan · #24 (**permalink**) 03-29-2011, 02:08 AM

Quote:

Originally Posted by Knotlob

I agree entirely with your sentiments Ragnarox. However, I merely provided a link to the article - I did not write it! Plain words are always best, but some professions (especially the legal ones) seem to like to hide behind their own particular vocabulary/jargon).

knotlob

I agree with you

RayBan · #25 (**permalink**) 03-29-2011, 02:10 AM

I agree with you

redraidermommy · #26 (**permalink**) 04-04-2011, 05:02 PM

Here is a good website that breaks down the different types of lenses (brands) by materials, and gives the water% and dk values.

http://www.clspectrum.com/article.aspx?article=103168

I think I found this website through another link on another lens thread. It's been very helpful for me when discussing lenses with my doc.

Deepurple · #27 (**permalink**) 04-04-2011, 05:40 PM

Quote:

Originally Posted by redraidermommy

Here is a good website that breaks down the different types of lenses (brands) by materials, and gives the water% and dk values.

http://www.clspectrum.com/article.aspx?article=103168

I think I found this website through another link on another lens thread. It's been very helpful for me when discussing lenses with my doc.

Thanks for the link redraidermommy. Leave it to a mommy to get the boys out of their Star Wars digression.

redraidermommy · #28 (**permalink**) 04-04-2011, 06:11 PM

Quote:

Originally Posted by Deepurple

Thanks for the link redraidermommy. Leave it to a mommy to get the boys out of their Star Wars digression.

That's my job now who wants to talk barbies or disney princesses?

Garfield21 · #29 (**permalink**) 04-07-2011, 01:19 PM

Quote:

Originally Posted by redraidermommy

That's my job now who wants to talk barbies or disney princesses?

Earlier today I saw someone quote that "Barbie Girl" song. Does that count?

redraidermommy · #30 (**permalink**) 04-07-2011, 05:46 PM

Quote:

Originally Posted by Garfield21

Earlier today I saw someone quote that "Barbie Girl" song. Does that count?

Ehhh, no, sorry that doesn't count. We like to keep the music and dolls "clean and free from offensive material" LMBO!

On a side note, that song came out when I was in high school....terrible memories attached

RedeyeJedi · #31 (**permalink**) 04-07-2011, 05:59 PM

Quote:

Originally Posted by redraidermommy

Ehhh, no, sorry that doesn't count. We like to keep the music and dolls "clean and free from offensive material" LMBO!

On a side note, that song came out when I was in high school....terrible memories attached

What kind of memories? The "lost love" kind of memories or "I can't believe I used to dress like that" memories?

captainneo · #32 (**permalink**) 08-15-2011, 11:11 AM

Quote:

Originally Posted by RedeyeJedi

What kind of memories? The "lost love" kind of memories or "I can't believe I used to dress like that" memories?

Excellent question, RedeyeJedi. Now we just have to wait for the answer.

Ragnarox · #33 (**permalink**) 08-15-2011, 05:36 PM

Quote:

Originally Posted by Kyleden

I don't want to get off on a tangent, but I have recently realized how often the word "blast" is used in Star Wars.

"Its markings match the description of a ship that blasted its way out of Mos Eisley."

"You're fortunate he doesn't blast you into a million pieces right here!"

"Open the blast doors!"

"Find the controls to extend the bridge!"
"I think I just blasted `em."

"With the blast shield down I can't even see, how am I supposed to fight?"

"Blast it Biggs, where are you?"

And so on. Did I miss any? I'm sure I did.

Did you do all those quotes from memory, Kyleden?

I'll bet you didn't see this coming.

Kyleden · #34 (**permalink**) 09-30-2011, 04:32 PM

Quote:

Originally Posted by Ragnarox

Did you do all those quotes from memory, Kyleden?

I'll bet you didn't see this coming.

It was a surprise to me.

She's got a nice bikini body, but she probably should get out of that armor and into the sun a little more often. She's as pale as the storm trooper uniform. Do they all look like that under the armor?

As a side note, imagine my surprise when I found out that Hitler had storm troopers about forty years before Darth Vader did.

SandiStix · #35 (**permalink**) 10-07-2011, 05:22 PM

Quote:

Originally Posted by captainneo

Excellent question, RedeyeJedi. Now we just have to wait for the answer.

Yeah, I'd like to read Redraidermommy's answer to that question, too. We just need to get her back now.

What I'd like to know is what's "offensive" about "Barbie Girl"? The only thing I can think of is that "undress me everywhere" part.

People who have never heard the song before are scratching their heads.

Well, Barbie did have a lot of outfits to choose from . . .

captainneo · #36 (**permalink**) 10-20-2011, 04:49 PM

Quote:

Originally Posted by SandiStix

Yeah, I'd like to read Redraidermommy's answer to that question, too. We just need to get her back now.

What I'd like to know is what's "offensive" about "Barbie Girl"? The only thing I can think of is that "undress me everywhere" part.

People who have never heard the song before are scratching their heads.

Well, Barbie did have a lot of outfits to choose from . . .

Anybody know if Barbie ever wore glasses? That would mean that she wasn't wearing her 1 Day Acuvue contact lenses.

Garfield21 · #37 (**permalink**) 10-27-2011, 04:53 PM

Quote:

Originally Posted by captainneo

Anybody know if Barbie ever wore glasses? That would mean that she wasn't wearing her 1 Day Acuvue contact lenses.

Of course Barbie wore glasses, and she looked good in them.

BettyBoop · #38 (**permalink**) 11-08-2011, 01:25 PM

Quote:

Originally Posted by Garfield21

Of course Barbie wore glasses, and she looked good in them.

Hey, nice work finding actual photographic evidence that Barbie has been known to wear glasses. It's confirmed!

SandiStix · #39 (**permalink**) 11-15-2011, 03:33 PM

Quote:

Originally Posted by BettyBoop

Hey, nice work finding actual photographic evidence that Barbie has been known to wear glasses. It's confirmed!

That's right, Betty. Let's slap a big Mythbuster-style "Confirmed" sign on that.

lacy88 · #40 (**permalink**) 11-19-2011, 12:24 AM

Once upon a time, there is a pair of Ray Ban sunglasses, accompanying him to live a quiet life.
One day, his distant relatives visit. Then, glasses and guest accidentally met each other, aside quietly began to chat. Guests glasses proudly told it:" I follow the master has been to many places, see sea sunrise, the sunset mountains, vast grasslands, torrent ... ...."
Since then, glasses and began to complain about their own lives a dull, not to see the beautiful view. Glasses day and night thinking, finally, it could not hold any more, and started to shake, suddenly, it "pa!" With a thud to the ground, be happy.
However, things are not so simple. No matter how hard glasses, it can not stand up, let alone walk. The owner then dog found it, think of glasses in the master nose cold at his eyes, thought it serves you right, so the glasses and gnaw bite, so that the glasses covered all over with cuts and bruises. Vent enough, he lost in the side. A mouse just passes by, discovered glasses, see it shining lens, jumped for joy:" cheep, give me children swing!" Then, the mice have glasses back to their home. Out of dark, what also can't see, glasses Miss near his master's life. It is regret, regret what you have done.
In remorse, glasses spent a long night......
One day, the little mouse dragged outside the glasses to play, then, a small mouse to pass by, leaving just glasses escaped back to the cave. The passerby picked it up, put on glasses, gave his grandmother. Thereafter, glasses with grandma read a book, newspaper.......
Ray Ban Sunglasses finally know the peaceful life is also a kind of happiness.

Deepurple · #41 (**permalink**) 11-29-2011, 03:39 PM

Quote:

Originally Posted by lacy88

Once upon a time, there is a pair of Ray Ban Sunglasses, accompanying him to live a quiet life.
One day, his distant relatives visit. Then, glasses and guest accidentally met each other, aside quietly began to chat. Guests glasses proudly told it:" I follow the master has been to many places, see sea sunrise, the sunset mountains, vast grasslands, torrent ... ...."
Since then, glasses and began to complain about their own lives a dull, not to see the beautiful view. Glasses day and night thinking, finally, it could not hold any more, and started to shake, suddenly, it "pa!" With a thud to the ground, be happy.
However, things are not so simple. No matter how hard glasses, it can not stand up, let alone walk. The owner then dog found it, think of glasses in the master nose cold at his eyes, thought it serves you right, so the glasses and gnaw bite, so that the glasses covered all over with cuts and bruises. Vent enough, he lost in the side. A mouse just passes by, discovered glasses, see it shining lens, jumped for joy:" cheep, give me children swing!" Then, the mice have glasses back to their home. Out of dark, what also can't see, glasses Miss near his master's life. It is regret, regret what you have done.
In remorse, glasses spent a long night......
One day, the little mouse dragged outside the glasses to play, then, a small mouse to pass by, leaving just glasses escaped back to the cave. The passerby picked it up, put on glasses, gave his grandmother. Thereafter, glasses with grandma read a book, newspaper.......
Ray Ban Sunglasses finally know the peaceful life is also a kind of happiness.

Well, that was . . . bizarre. What does that have to do with 1-Day Acuvue contact lenses? If you're a real person, and not some random word generator, you should be able to answer me.

paule123 · #42 (**permalink**) 01-19-2012, 02:45 AM

Quote:

Originally Posted by nicholas

Although it's generally true, I don't think higher water content always equals higher Dk with hydrogels. For the most part it's true though. With silicone hydrogels, the silicone is responsible for the oxygen permeability, and silicone is hydrophobic (water-repelling). Silicone hydrogels have lower water contents but can have many times the Dk of traditional hydrogel materials. It's really apples and oranges, that's why it's confusing.

thanks for the answer, i am also looking for this thing

Teddikitty · #43 (**permalink**) 01-19-2012, 10:53 AM

Quote:

Originally Posted by Deepurple

Well, that was . . . bizarre. What does that have to do with 1-Day Acuvue contact lenses? If you're a real person, and not some random word generator, you should be able to answer me.

Nothing so far, Deepurple. It least it makes some kind of sense and isn't just a random jumble of words.