Friday, March 9, 2012

The Truth About Acuvue 2

First off, I don't want anyone to think that I am picking on Acuvue as a company.  I wore Acuvue 2's very happily until I got to optometry school.  And I thought I was supposed to wear them for a month at a time.  I was just like so many of my patients, overwearing my lenses due to poor information.  This post is for all of those misinformed people like my younger self, who may be permanently harming their eyes by incorrectly wearing their contact lenses.

IS ACUVUE 2 A HEALTHY LENS?

Yes, when worn properly.  If you dispose your lenses every 2 weeks, and do not sleep in them, then Acuvue 2 can be a perfectly healthy lens.  Remember, the cornea gets all of its oxygen from the atmosphere, so contact lenses must allow oxygen to pass through.  The amount of oxygen passing through to the cornea in an Acuvue 2 lens is 33 Dk/t (this is a unit describing the rate of oxygen passing through the lens).  Newer lenses (like Biofinity, Acuvue Oasys, and Air Optix Aqua) have Dk/t values over 100!  So as you can see, Acuvue 2 lenses have significantly less oxygen to the eye than newer products.  To be safe for overnight wear, studies have shown that lenses have to have at a minimum of 80 Dk/t (and even this shows some signs of corneal swelling the next morning).  This means Acuvue 2 lenses are absolutely not healthy to be slept in!

WHY DID MY DOCTOR MAKE ME CHANGE BRANDS FROM ACUVUE 2?
There are 2 reasons that I switch a person from a brand they like:
1) They are overwearing their lenses past the FDA approved wear time.  If you are sleeping in your lenses or want to wear your lenses longer than 2 weeks, we have to change to a different contact lens brand and material that is approved and healthy for that amount of wear.
2) They are suffering from damage to their cornea.  Some people can wear their lenses correctly, and still have consequences from poor oxygen flow to the eye.  Any time I see corneal neovascularization (the growth of blood vessels into the cornea, which is supposed to be a clear tissue) I know that the cornea needs more oxygen than it is getting.  Contact lens acute red eye, giant papillary conjunctivitis, and corneal scars are other indicators.  See this post for more information.

Corneal Neovascularization: it looks like chronic redness in the mirror, but under the microscope your doctor can see individual anomalous blood vessels that have entered the clear tissue of your cornea


I HAVE TRIED OTHER LENSES, BUT NOTHING FEELS AS GOOD AS ACUVUE 2
I hear this all the time from my patients.  Acuvue lenses are VERY comfortable, and it can sometimes be hard to find a lens that feels as good.  Lenses that have more oxygen to the eye are generally made of a different material called Silicone Hydrogel.  In some patients, this material can cause more depositing, making vision more blurry through the day than when they wore their old hydrogel lenses.  This only happens to a small percentage of patients, but it is a definite possibility. Almost every patient will experience some "tingling" sensation within the first month or two after changing lenses, but this is actually a good side effect.  This tingling means that the cornea is being stimulated by the extra oxygen, and the damaged corneal nerves are regenerating.  If you can make it through this transition period, the new lenses are going to be comfortable and more healthy.

TAKE HOME POINTS:
Acuvue 2's can be healthy lenses when worn properly.  This means NO sleeping in the contact lenses, and throwing them away every 2 weeks.  If your doctor sees signs of corneal damage, a change in lenses might still be necessary.  As an optometrist, I want to reassure everyone that we don't have a grudge against your lenses, we just have seen the complications from unhealthy contact lens wear and don't want to see that happen to you!

3 comments:

  1. Thank you! Great info. I was looking for dk/t values, and moisture content as I have dry eye. I last bought Acuvue MOIST (dK/t 35) before I knew the dk/t values of oasys lenses. The Oasys have the low moisture content my dry eyes like, but aren't available as dailies. The Acuvue TrueEye has a slightly higher moisture content, and moderate dk/t of 65. I've been managing with the Moist, but I think I'm going to switch to the TruEye. They're about 30% more expensive.

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  2. This is an interesting article. I am also an optometrist and was researching Acuvue 2. I agree that it can be a fine lens if worn properly, but how many patients really wear it properly? That is the key question. However, the reason I am posting is an odd find during my research which I don't recall being taught in school. According to the Acuvue website AND Tyler's Quarterly, AV 2 is approved for up to 7 nights extended wear and then thrown away. I am like you and believe the more oxygen the better to maintain proper health for the eye. I just found that odd. It won't change my recommendations to higher oxygen lenses, but I thought I would pass that information along and hear your thoughts on the matter.

    As to answer Matthew's comment, There are other lens companies out there too. Keep this in mind. Some doctors have their "favorites," but there are always options. You could look into CooperVision Proclear 1-Day. They are still a lower dk lens, but the omafilcon A material has shown to improve comfort in relation to dryness. I have actually had a lot of luck with CooperVision Clearsight 1 Day or Alcon Dailies Aquacomfort Plus. The nice thing about the Alcon Dailies, they have a blinking moisture release component built it that is supposed to maintain moisture release throughout the day. But it doesn't seem to work for everyone. I'm not hating on Acuvue at all, but just be aware of other companies and their lens offerings. There isn't any reason why you should "manage" with a lens when you can be comfortable.

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  3. Acuvue has always preached their rule of thumb: 14 days of wear or 7 days and nights. I agree with you Seth that with dk/t values that low, we are not coming close to meeting the new recommended minimums for overnight wear in a product like Acuvue 2. I would never advise it to be worn that way simply due to the massive amounts of superior lenses on the market that could be slept in without as many risks.

    For Mat: There are a ton of new dailies launching in the market right now that are made from entirely new materials, meant to give the eye higher oxygen and deliver moisture in an entirely new method. At your next exam, see if your doctor could let you try B +L's Biotrue One Day or DAILIES TOTAL 1 by Ciba.

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