Flak 2.0 - lens thickness

[dancop]

I've got my first Oakley's today. I went with Flak 2.0 with Prism Everyday Grey Polarized lenses.
IMHO it looks great and the field of vision is really good.

But I have some questions.
I've got prescription for -4.75 and -3.75. The lenses are much more thicker than I expected. The left lens sits deep on my cheek and it is really annoying. I have replaced the nose part for those thicker ones and its much better now but still - the lenses are much thicker than my current ones.
I've made some measurements and my current lenses are about 3.6 mm thick and the Oakleys are 5mm and 6mm on the bottom edges. This is massive difference.

 

[Broccoli]

That’s wild.

 

[Dbninc]

Are your previous lenses glass?

 

[dancop]

Are your previous lenses glass?

No, plastic Transitions gen 7 I think. Right is the same power as in Oakleys (-3.75), left is slightly weaker -4.5, but 0.25 should not translate to 2.4mm difference in thickness.

 

[Oak Heel]

Better get someone like @Chris A Hardaway to verify, but I’m pretty sure your new lenses are thicker bc the Flak lenses have a higher base curve on the front vs your old glasses.

 

[KarlBlessing]

Can you get the same prescription in the non-XL version of the lens since you can pop them into the same frame? (if that's still applicable to prescription orders)

Maybe that little bit less height will not impact your cheeks, especially since your old pair don't seem to have as large a vertical coverage.

And what Oak said, the front isn't as "flat" as your old pair, so more corrective thickness is needed to match the prescription from the base curve.

 

[Atticus]

No, plastic Transitions gen 7 I think. Right is the same power as in Oakleys (-3.75), left is slightly weaker -4.5, but 0.25 should not translate to 2.4mm difference in thickness.

You from PA?

 

[dancop]

You from PA?

Definitely not Just over 4500 miles east

 

[Chris A Hardaway]

I've got my first Oakley's today. I went with Flak 2.0 with Prism Everyday Grey Polarized lenses.
IMHO it looks great and the field of vision is really good.

But I have some questions.
I've got prescription for -4.75 and -3.75. The lenses are much more thicker than I expected. The left lens sits deep on my cheek and it is really annoying. I have replaced the nose part for those thicker ones and its much better now but still - the lenses are much thicker than my current ones.
I've made some measurements and my current lenses are about 3.6 mm thick and the Oakleys are 5mm and 6mm on the bottom edges. This is massive difference.

View attachment 883670

View attachment 883671

You are comparing apples to oranges my friend.

As @Oak Heel said, when you increase the front base curve, it increases the back base curve to be extremely thick.

If I were you I'd consider myself lucky that Oakley technology even allows that Rx in a wrap. In the good old days 10 years ago you could only go up to a -3.00 on a wrap and it'd be extremely distorted and chunky beyond that.

Also, your old frame is way smaller.. Probably like a 52 mm width (my guess) and flak 2.0 xl is more like a 60 mm width (estimated again)... Diagonal your old lenses might be 54-55mm tops, new flak 2.0 xl is about 68ish mm wide.

So 1) curve, 2) increased diameter of lenses needed. And lastly:

3) oakleys are made to be safe and impact resistant, so minimum center thickness would be 2.0 mm

You need a caliper to measure the centers. Your old glasses were probably between 1.2 and 1.6mm in center. These are probably 2.0 to 2.2 mm in center.

Considering your eyes needs, if your vision is good, Oakley did an excellent job. From a physics and engineering stand point .... That is, unless you measure the center and its 2.5mm or above. Then they need to regrind / redo thinner.

Pro tip. Measure center, they can't make edges thinner, that would make your RX weaker and incorrect.

 

[Oak Heel]

You are comparing apples to oranges my friend.

As @Oak Heel said, when you increase the front base curve, it increases the back base curve to be extremely thick.

If I were you I'd consider myself lucky that Oakley technology even allows that Rx in a wrap. In the good old days 10 years ago you could only go up to a -3.00 on a wrap and it'd be extremely distorted and chunky beyond that.

Also, your old frame is way smaller.. Probably like a 52 mm width (my guess) and flak 2.0 xl is more like a 60 mm width (estimated again)... Diagonal your old lenses might be 54-55mm tops, new flak 2.0 xl is about 68ish mm wide.

So 1) curve, 2) increased diameter of lenses needed. And lastly:

3) oakleys are made to be safe and impact resistant, so minimum center thickness would be 2.0 mm

You need a caliper to measure the centers. Your old glasses were probably between 1.2 and 1.6mm in center. These are probably 2.0 to 2.2 mm in center.

Considering your eyes needs, if your vision is good, Oakley did an excellent job. From a physics and engineering stand point .... That is, unless you measure the center and its 2.5mm or above. Then they need to regrind / redo thinner.

Pro tip. Measure center, they can't make edges thinner, that would make your RX weaker and incorrect.

Outstanding explanation and insight, like always!