Severe power mismatch between Air Optix and Biofinity

A: Air Optix plus HydraGlyde
B: Biofinity
cm: cm to blur
D: corresponding diopters
R: right eye
L: left eye

The power of both A and B lenses is -7.00, 0.00 CYL.


cm -92 -28
D -8.12 -2.50
SE -9.37

cm -68 -33
D -8.50 -1.62
SE -9.25


cm -124 -31
D -7.75 -2.37
SE -8.87

cm -83 -36
D -8.25 -1.50
SE -9.00

So, either Alcon underpowers their lenses up to half a diopter or CooperVision overpowers Biofinity lenses up to the same amount.

No one knows why or haven’t used these lenses?

What about Acuvue Oasys?

I think you are the only one to have done such a test! so cannot comment

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Very interesting. Keep us posted on what you learn. I have now ordered glasses from five different online providers, so I’m going to be doing some comparisons myself!

I used all 3 of them, but with -2D and without cyl. I didn’t notice a difference in strength, but the differences in curve, diameter and general comfort (moving around on the eye after a blink, oxygen, dry eyes) were obvious.

I’d believe the difference in strength you experience is caused by the added cylinder combined with high myopia. They may have differences in how they add cylinder and weight to the bottom of the lenses. And how precise they are. The difference may not be intentional at all as manufacturing lenses for the range above -8D is still an experimental area in my view, as the difference in distance to blur shrinks so much in that range.

I’d suggest settling with the most comfortable brand and just choose a strength that works for you and start reducing from there. As you get in to the mid or low range, the difference will be less and less or none.

But an interesting finding nevertheless.

I can read my computer well without any cylinder (-7.00 lenses 60-75 cm still readable).

Combined with rotational discomfort toric lenses cause (I do a lot of head rotation during day), I decided to forgo cylinder :blush: so that’s not the cause… Right eye most myopic axis is now clear 1-2 cm farther, so I’d stick with this (I do minus on minus strategy - minus glasses for distance coming soon).

Sometimes I use glasses as differentials. They are with full cylinder on one eye and undercorrected on other. Anyway, I have a bad time returning to contacts w/o cylinder, since my brain fails to recognise characters that much after a while of relaxation.

I noticed that vertical lines are much clear in right eye than left in equal Biofinity CLs.
That’s normal since the difference between eyes of least myopic axis is 0.25-0.50 D.

But when I bought first Alcon, I decided to replace on right eye first.
Then, left eye begun to see almost better!
I quickly figued out my vision was like that in Biofinity vs Alcon -8s with cylinder (Alcon did much blurrier).
So, I disciplined myself to take such a test. Thanks for reviewing…

Glasses w/ high power could have power errors.

For example, I wore -9.00 CYL -1.50 OU and left eye seen way much worse than it was supposed to in an equal correction.

While accidentally came up to a vertexometer (a device that measures lens powers), I realized right eye wore -9.25 CYL -1.25 and not -9.00 CYL -1.50 as in Rx.

Good for you :slight_smile:
This will surely help you a lot with contact lens wearing.

Otherwise just accept that diopters of contact lenses in your range are as accurate as shoe sizes. Same ones can mean completely different - brand by brand.

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