acuvue 2 color contacts-question

dtallarida · #1 (**permalink**) 05-19-2010, 08:27 PM

i currently have Acuvue 2 contacts with a BC of 8.7. i want to try the opaque acuve 2 color contacts, but they only come in BC 8.3.

I know i am supposed to see my doctor regarding this but at this time i am unable to. i am wondering what risk i am taking by ordering the BC 8.3?

Knotlob · #2 (**permalink**) 05-20-2010, 04:37 AM

Quote:

Originally Posted by dtallarida

i currently have Acuvue 2 contacts with a BC of 8.7. i want to try the opaque acuve 2 color contacts, but they only come in BC 8.3.

I know i am supposed to see my doctor regarding this but at this time i am unable to. i am wondering what risk i am taking by ordering the BC 8.3?

Hello dtallarida

Welcome to the forum

What is your prescribed base curve - do you know?

The problem with going to a base curve of 8.3 is that it is quite a big difference to 8.7, though soft lenses are pretty tolerant of fit. But the 8.3mm BC may be too tight for you and then the lens may not float properly on your cornea. This then can interfere with the tear film, which can reduce the follow of oxygen to your cornea and lead to neovascularisation, where capillaries grow into the cornea. The cornea is naturally free of capillaries for sharp vision.

You really must see an contact lens specialist. Don't gamble with your eyesight. If you get neovascularisation, the capillaries will not go away, but will remain as ghost capillaries, even after the oxygen deprevation problem has been fixed.

knotlob

dtallarida · #3 (**permalink**) 05-20-2010, 06:58 AM

thank you for replying.

my prescription says my BC is 8.7. guess i won't be getting colored contacts

Jubert · #4 (**permalink**) 05-20-2010, 08:48 AM

Quote:

Originally Posted by dtallarida

thank you for replying.

my prescription says my BC is 8.7. guess i won't be getting colored contacts

Hi dtallarida,

Welcome to Lens 101. I give you credit for asking this question instead of just trying to order contact lenses. You probably wouldn't be able to get them anyway, because the contact lens company will ask to see a copy of your prescription, and if they see your prescribed base curve is 8.7, they won't sell you an 8.3.

I looked around Lens.com and I found a lot of color contacts that have an 8.6 base curve, but I didn't find an 8.7 until I got to Expressions Accents. So the next time you see your eye doctor, ask him or her about Expressions Accents contact lenses, or the possibility of wearing contacts with an 8.6 base curve.

Check out this page of color contacts:

http://www.lens.com/contact-lenses/department95.asp

dtallarida · #5 (**permalink**) 05-20-2010, 08:50 AM

i actually came across the focus monthly contacts but realized they only work with light eyes. i have brown eyes and would need an opaque lens.

thank you for your help

Building63 · #6 (**permalink**) 05-20-2010, 09:58 AM

Quote:

Originally Posted by dtallarida

i actually came across the focus monthly contacts but realized they only work with light eyes. i have brown eyes and would need an opaque lens.

thank you for your help

Hi dtallarida, and welcome to Lens 101.

If you're wanting to cover brown eyes, you might try Acuvue 2 Colours - Opaques. They come in Deep Blue, Chestnut Brown, Pearl Gray, Jade Green, Hazel Green, Warm Honey, and Sapphire Blue. http://www.lens.com/contact-lenses/lens134.asp

dtallarida · #7 (**permalink**) 05-20-2010, 10:01 AM

Quote:

Originally Posted by Building63

Hi dtallarida, and welcome to Lens 101.

If you're wanting to cover brown eyes, you might try Acuvue 2 Colours - Opaques. They come in Deep Blue, Chestnut Brown, Pearl Gray, Jade Green, Hazel Green, Warm Honey, and Sapphire Blue. http://www.lens.com/contact-lenses/lens134.asp

that is my problem- the acuvue 2 colors opaque would be perfect but they only come in a BC of 8.3 and my prescription says BC 8.7. is the size difference significant?

Logopolis · #8 (**permalink**) 05-20-2010, 10:58 AM

Quote:

Originally Posted by dtallarida

that is my problem- the acuvue 2 colors opaque would be perfect but they only come in a BC of 8.3 and my prescription says BC 8.7. is the size difference significant?

Yes, the size difference is significant. If the contacts were an 8.6 base curve, then maybe they could work, but it's doubtful that an 8.3 would fit comfortably. It looks like Building 63 did not scroll up to see your first post.

How about the Expressions Accent contacts that Jubert recommended? Do you think they would be dark enough to cover your brown eyes?

dtallarida · #9 (**permalink**) 05-20-2010, 11:41 AM

Quote:

Originally Posted by Logopolis

Yes, the size difference is significant. If the contacts were an 8.6 base curve, then maybe they could work, but it's doubtful that an 8.3 would fit comfortably. It looks like Building 63 did not scroll up to see your first post.

How about the Expressions Accent contacts that Jubert recommended? Do you think they would be dark enough to cover your brown eyes?

the expressions contacts have a base curve of 8.7 but the diameter is 14.4 and i need a 14.0. is that a significant change in diameter?

ICU2 · #10 (**permalink**) 05-20-2010, 01:28 PM

Quote:

Originally Posted by dtallarida

the expressions contacts have a base curve of 8.7 but the diameter is 14.4 and i need a 14.0. is that a significant change in diameter?

The base curve of a contact lens measured how round it is. If you were to take the curve formed by the back surface of say, a 14.0 base curve contact lens, and make it into a full circle, that circle would have a radius of 14.0 millimeters. If your geometry is a little fuzzy, that means the circle is 14 millimeters from center to edge.
The diameter, on the other hand, is the distance from one edge of the lens to the opposite edge.
Now maybe you see why the base curve has to match the curve of your eye pretty closely, but the diameter is less important. I've never fit contact lenses before, so I don't know how close to your prescription you have to be. .4 millimeters doesn't seem like a lot to me, but your eye doctor may disagree. Remember also that a contact lens sits directly on the most sensitive tissue in your body. If the fit isn't pretty much exactly right, you're not going to be very happy.

Knotlob · #11 (**permalink**) 05-21-2010, 04:07 AM

Quote:

Originally Posted by ICU2

The base curve of a contact lens measured how round it is. If you were to take the curve formed by the back surface of say, a 14.0 base curve contact lens, and make it into a full circle, that circle would have a radius of 14.0 millimeters. If your geometry is a little fuzzy, that means the circle is 14 millimeters from center to edge.
The diameter, on the other hand, is the distance from one edge of the lens to the opposite edge.
Now maybe you see why the base curve has to match the curve of your eye pretty closely, but the diameter is less important. I've never fit contact lenses before, so I don't know how close to your prescription you have to be. .4 millimeters doesn't seem like a lot to me, but your eye doctor may disagree. Remember also that a contact lens sits directly on the most sensitive tissue in your body. If the fit isn't pretty much exactly right, you're not going to be very happy.

Yeap. Diameter is less critical. If you want coloured contact lenses, why not see your eye care professional? He/she may have free trial ones and can see if these particular lenses (even with a 8.3mm base curve) would suit you. Only they can say if the fit is acceptable.

Alternatively they may suggest an alternative. What we are saying is don't try to fit your own contact lenses as you may cause problems for your eyes.

knotlob

dtallarida · #12 (**permalink**) 05-21-2010, 06:31 AM

Quote:

Originally Posted by Knotlob

Yeap. Diameter is less critical. If you want coloured contact lenses, why not see your eye care professional? He/she may have free trial ones and can see if these particular lenses (even with a 8.3mm base curve) would suit you. Only they can say if the fit is acceptable.

Alternatively they may suggest an alternative. What we are saying is don't try to fit your own contact lenses as you may cause problems for your eyes.

knotlob

because then i would have to pay another $125 for the exam...which i just did2 weeks ago.

Knotlob · #13 (**permalink**) 05-21-2010, 08:48 AM

Quote:

Originally Posted by dtallarida

because then i would have to pay another $125 for the exam...which i just did2 weeks ago.

Well it depends on what value you put on your eyesight !! I reckon eyesight is the most important sense, so try not to take too many risks with it.

Perhaps you could ask for a discount since your optician has already done a lot of the initial checking of your eyes, though would still have some work to do with the new lenses. If you don't ask, then you won't get any discount/rebate.

knotlob

KSCbase · #14 (**permalink**) 05-21-2010, 09:00 AM

Quote:

Originally Posted by Knotlob

Well it depends on what value you put on your eyesight !! I reckon eyesight is the most important sense, so try not to take too many risks with it.

Perhaps you could ask for a discount since your optician has already done a lot of the initial checking of your eyes, though would still have some work to do with the new lenses. If you don't ask, then you won't get any discount/rebate.

knotlob

That's a good idea, knotlob. I hope that works for you, dtallarida. Let us know.

Totriet · #15 (**permalink**) 06-08-2010, 05:13 PM

Hi, dtallarida and hi everybody!

Dtallarida I am exactly in the same situation, I find this lens model

http://www.contactlenses.co.uk/details287_130.html?&fuseaction=store.details&lens priceId=287&lensentryId=130&currencyid=12

B.C :8.7 and diameter: 14

I think, I will place an order this week

KITT · #16 (**permalink**) 06-09-2010, 10:55 AM

Quote:

Originally Posted by Totriet

Hi, dtallarida and hi everybody!

Dtallarida I am exactly in the same situation, I find this lens model

http://www.contactlenses.co.uk/details287_130.html?&fuseaction=store.details&lens priceId=287&lensentryId=130&currencyid=12

B.C :8.7 and diameter: 14

I think, I will place an order this week

Looks like you found Soflens Natural Colors, and it looks like they are available in an 8.7 base curve and a 14 diameter.

KITT · #17 (**permalink**) 06-09-2010, 11:00 AM

Quote:

Originally Posted by ICU2

The base curve of a contact lens measured how round it is. If you were to take the curve formed by the back surface of say, a 14.0 base curve contact lens, and make it into a full circle, that circle would have a radius of 14.0 millimeters. If your geometry is a little fuzzy, that means the circle is 14 millimeters from center to edge.
The diameter, on the other hand, is the distance from one edge of the lens to the opposite edge.

So, wait, my geometry is a little fuzzy too. If the base curve measures the radius, and the radius is the distance from center to edge, wouldn't it be exactly half the diameter, making a lens with a base curve of 14 have a diameter of 28?

Knotlob · #18 (**permalink**) 06-09-2010, 01:24 PM

Quote:

Originally Posted by KITT

So, wait, my geometry is a little fuzzy too. If the base curve measures the radius, and the radius is the distance from center to edge, wouldn't it be exactly half the diameter, making a lens with a base curve of 14 have a diameter of 28?

If you were talking about a flat disk with a diameter of 14mm, then the radius of this flat disk would indeed be 14/2 - 7.0mm.

But the base curve/radius is something else. The contact lens is not a flat disk but is like a soup bowl in shape - i.e. it is 'dished'. The base curve refers to the curvature of the bowl from it's circumference down into the middle bottom of the of the inside of the bowl.

knotlob

yournamehere · #19 (**permalink**) 06-09-2010, 03:33 PM

Quote:

Originally Posted by Knotlob

If you were talking about a flat disk with a diameter of 14mm, then the radius of this flat disk would indeed be 14/2 - 7.0mm.

But the base curve/radius is something else. The contact lens is not a flat disk but is like a soup bowl in shape - i.e. it is 'dished'. The base curve refers to the curvature of the bowl from it's circumference down into the middle bottom of the of the inside of the bowl.

knotlob

Well done, knotlob. That's a very good reason why d does not equal 2r when it comes to contact lenses.

Jubert · #20 (**permalink**) 07-08-2010, 03:22 PM

Quote:

Originally Posted by dtallarida

because then i would have to pay another $125 for the exam...which i just did2 weeks ago.

How are you doing dtallarida? Have you found any contacts with a color you like, in a base curve and diameter that will fit you?

Building63 · #21 (**permalink**) 07-08-2010, 04:21 PM

Quote:

Originally Posted by Knotlob

If you were talking about a flat disk with a diameter of 14mm, then the radius of this flat disk would indeed be 14/2 - 7.0mm.

But the base curve/radius is something else. The contact lens is not a flat disk but is like a soup bowl in shape - i.e. it is 'dished'. The base curve refers to the curvature of the bowl from it's circumference down into the middle bottom of the of the inside of the bowl.

knotlob

That's true, I didn't take into account the curved bowl shape of the contact lens either. Thanks knotlob.

Logopolis · #22 (**permalink**) 07-09-2010, 02:56 PM

Quote:

Originally Posted by dtallarida

i currently have acuvue 2 contacts with a BC of 8.7. i want to try the opaque acuve 2 color contacts, but they only come in BC 8.3.

I know i am supposed to see my doctor regarding this but at this time i am unable to. i am wondering what risk i am taking by ordering the BC 8.3?

Hi dtallarida. In this posting you said that you were unable to see a doctor for a prescription "at this time." Has there been a better time since, so you could get a proper fitting for your contacts?

KSCbase · #23 (**permalink**) 07-12-2010, 04:37 PM

Quote:

Originally Posted by KITT

Looks like you found Soflens Natural Colors, and it looks like they are available in an 8.7 base curve and a 14 diameter.

Natural Touch Opaque contact lenses are also available in those parameters as well: http://www.lens.com/contact-lenses/lens290.asp

ICU2 · #24 (**permalink**) 07-13-2010, 11:59 AM

Quote:

Originally Posted by Knotlob

Yeap. Diameter is less critical. If you want coloured contact lenses, why not see your eye care professional? He/she may have free trial ones and can see if these particular lenses (even with a 8.3mm base curve) would suit you. Only they can say if the fit is acceptable.

Alternatively they may suggest an alternative. What we are saying is don't try to fit your own contact lenses as you may cause problems for your eyes.

knotlob

Yes, trial lenses. Good call.

yournamehere · #25 (**permalink**) 07-29-2010, 10:35 AM

Quote:

Originally Posted by Knotlob

If you were talking about a flat disk with a diameter of 14mm, then the radius of this flat disk would indeed be 14/2 - 7.0mm.

But the base curve/radius is something else. The contact lens is not a flat disk but is like a soup bowl in shape - i.e. it is 'dished'. The base curve refers to the curvature of the bowl from it's circumference down into the middle bottom of the of the inside of the bowl.

knotlob

Wait a minute. Reading this post again I have another question. Wouldn't the curve of the contact lens affect both the radius and the diameter the same way? So even with something bowl-shaped like a contact lens, wouldn't the diameter still be twice the radius?

Knotlob · #26 (**permalink**) 07-29-2010, 12:59 PM

Quote:

Originally Posted by yournamehere

Wait a minute. Reading this post again I have another question. Wouldn't the curve of the contact lens affect both the radius and the diameter the same way? So even with something bowl-shaped like a contact lens, wouldn't the diameter still be twice the radius?

No, a contact lens is not a sphere.

Try thinking of the lens as a soup plate sitting waiting to be filled. The diameter is measured horizontally across the top of the plate.

The radius, which opticians quote for contact lenses, is measured vertically from the centre top of the plate down to the bottom of the plate. It has no relation to the diameter of the plate.

knotlob

UNIT · #27 (**permalink**) 07-30-2010, 10:49 AM

Quote:

Originally Posted by Knotlob

No, a contact lens is not a sphere.

Try thinking of the lens as a soup plate sitting waiting to be filled. The diameter is measured horizontally across the top of the plate.

The radius, which opticians quote for contact lenses, is measured vertically from the centre top of the plate down to the bottom of the plate. It has no relation to the diameter of the plate.

knotlob

Let me see if I understand.
So basically the radius follows the base curve of the contact lens, but the diameter does not, it's just measured edge-to-edge?

Knotlob · #28 (**permalink**) 07-30-2010, 11:02 AM

Quote:

Originally Posted by UNIT

Let me see if I understand.
So basically the radius follows the base curve of the contact lens, but the diameter does not, it's just measured edge-to-edge?

Yes, correct.

knotlob

OrganicPete · #29 (**permalink**) 07-30-2010, 02:23 PM

Quote:

Originally Posted by Knotlob

Yes, correct.

knotlob

Nice work, UNIT, and thanks to Knotlob for making the judgment call.

KITT · #30 (**permalink**) 08-05-2010, 11:29 AM

Quote:

Originally Posted by Knotlob

If you were talking about a flat disk with a diameter of 14mm, then the radius of this flat disk would indeed be 14/2 - 7.0mm.

But the base curve/radius is something else. The contact lens is not a flat disk but is like a soup bowl in shape - i.e. it is 'dished'. The base curve refers to the curvature of the bowl from it's circumference down into the middle bottom of the of the inside of the bowl.

knotlob

I see. So the curved shape of the contact lens makes the diameter a bit more than twice the radius. Why don't they measure the radius the same way?

Knotlob · #31 (**permalink**) 08-05-2010, 11:37 AM

Quote:

Originally Posted by KITT

I see. So the curved shape of the contact lens makes the diameter a bit more than twice the radius. Why don't they measure the radius the same way?

They are two completely separate measurements.

The base curve is normally around 8.6mm and gives the contact lens it's dished shape. If it were a flat disk, then the base curve would be extremely high - infinity.

The base curve radius has no relationship with the diameter of the lens - they are two different design parameters.

knotlob

Unclelar · #32 (**permalink**) 08-05-2010, 11:47 AM

Quote:

Originally Posted by Knotlob

They are two completely separate measurements.

The base curve is normally around 8.6mm and gives the contact lens it's dished shape. If it were a flat disk, then the base curve would be extremely high - infinity.

The base curve radius has no relationship with the diameter of the lens - they are two different design parameters.

knotlob

That's interesting knotlob. However, I think I'm as confused as KITT. How can the base curve have no relationship to the diameter? Isn't that like saying that the diameter of a circle has nothing to do with its circumference?
Forgive me if that's a stupid question, it just seems to me that if you changed the diameter of a contact lens, you would also change its curvature. Maybe I'm wrong about that.

Knotlob · #33 (**permalink**) 08-05-2010, 12:04 PM

Quote:

Originally Posted by Unclelar

That's interesting knotlob. However, I think I'm as confused as KITT. How can the base curve have no relationship to the diameter? Isn't that like saying that the diameter of a circle has nothing to do with its circumference?
Forgive me if that's a stupid question, it just seems to me that if you changed the diameter of a contact lens, you would also change its curvature. Maybe I'm wrong about that.

The diameter of a circle is of course related to it's circumference. But what I am trying to get across is that the diameter of the lens is measured in the horizontal plane (typically 14.2mm), whereas the base curve is measured in the vertical plane. They are two completely different measurements.

Maybe it is easier to think of the base curve of a flat saucer as being very high, but the base curve of a soup bowl being smaller and therefore the soup bowl has a tighter radius and is 'deeper'. You could in theory have a saucer and a soup bowl of the same diameter, but their 'base curves' would be different - big for the saucer and small for the soup bowl.

knotlob

madeinshades · #34 (**permalink**) 08-05-2010, 01:20 PM

Quote:

Originally Posted by Knotlob

The diameter of a circle is of course related to it's circumference. But what I am trying to get across is that the diameter of the lens is measured in the horizontal plane (typically 14.2mm), whereas the base curve is measured in the vertical plane. They are two completely different measurements.

Maybe it is easier to think of the base curve of a flat saucer as being very high, but the base curve of a soup bowl being smaller and therefore the soup bowl has a tighter radius and is 'deeper'. You could in theory have a saucer and a soup bowl of the same diameter, but their 'base curves' would be different - big for the saucer and small for the soup bowl.

knotlob

Knotlob, you've been very patient explaining this base curve/radius thing to those of us who don't quite get it. Thank you for taking the time to explain rather than just saying "It's so simple! Duh!"
I think I understand it now, and I hope Unclelar is no longer confused.

Jubert · #35 (**permalink**) 08-27-2010, 12:02 PM

Quote:

Originally Posted by Knotlob

Maybe it is easier to think of the base curve of a flat saucer as being very high, but the base curve of a soup bowl being smaller and therefore the soup bowl has a tighter radius and is 'deeper'. You could in theory have a saucer and a soup bowl of the same diameter, but their 'base curves' would be different - big for the saucer and small for the soup bowl.

knotlob

Thanks for that saucer and soup bowl analogy. I found it very helpful.

Building63 · #36 (**permalink**) 08-27-2010, 01:31 PM

Quote:

Originally Posted by dtallarida

that is my problem- the acuvue 2 colors opaque would be perfect but they only come in a BC of 8.3 and my prescription says BC 8.7. is the size difference significant?

Oh, right. Sorry. That's a pretty big difference. It would be like wearing a size 7 and trying to squeeze into a size 3.
Okay, maybe not that severe, since we're talking about millimeters here, but that's still a difference of four sizes, not just one. 8.3 would be too tight on you and they wouldn't sit right on your eyes. You might be able to get by with an 8.5, but if you tried to wear a pair of contacts with an 8.3 base curve, I think you'd be pretty uncomfortable.
Have you thought about custom made contact lenses? They're a little on the pricey side, but in your case it might just be worth it.