# Optical Forums > Progressive Lens Discussion Forum >  Physio or Comfort  Enhanced vs DRX version

## hlstavn

Anyone have a preference for a Comfort or Physio between the "Enhanced version" which I think is dual add, and the DRX version which I think is back surface. Its so great to have 3 different versions of a lens with the same name on them.Is there a Natural enhance? Some day a forward thinking perosn will come out with a lens with one name and one design at one price we can just trust. Or course then Essilor would come by and put 3 names on it at 3 different prices.

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## kentmitchell1961

We do nothing but the enhanced versions here and people love 'em..

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## hlstavn

I like the enhanced too, but the Drx is slightly cheaper.  One of my questions is how the design you pick affects the corridor length. These are unknown.









> We do nothing but the enhanced versions here and people love 'em..

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## nclairmore

I use the Physio Enhanced and have very good reviews.

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## DanLiv

The Comfort and Physio Enhanced have variable corridors from 14-25. The DRxs are still fixed at 17 or 14 corridors. Plus Physio Enhanced employs there WAVE2 tech, over the Physio/DRx original WAVE. That only matters if you drink the E-Kool-Aid though. We use only Enhanced and other variable corridor designs to eliminate seg height fudging of the past.

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## sharpstick777

Its important to understand the difference between Comfort and Physio series first.  The Comfort was released in 1993 and faced competition from the ST-28, as a result the Reading stays wide in every add power.  Its an adaptive design (the very first) so as the add power increases the lens changes, as a result with each increase in Add (inherently increasing distortion) the distortion moves up and in, reducing the the distance and intermediate width.  The Physio was designed in response to those issues, so it too is an adaptive design, but was designed to keep the distance  zones wider in every add power.  But as the Add power increases, and thus the distortion (Minkwitz) the lens grows a little harder and the corridor narrows.  This holds true throught the series, Traditional, Ehanced and DRx.

The Enhanced version is a hybrid design (partially free-form), the DRx versions are 100% Free-form.  The advantage of Free-form is not in just the accuracy, but to be able to control all the curves that link the distance and reading portions of the lens together both in and outside the intermediate corridor.  Hybrid lenses have some or all of the add cast, and so these curves cannot be fully optimized.  Its very difficult to lift a heavy man out of a deep hole, so a hybrid design will never offer the best or full advantages of free-form.  Cast front side add powers can do terrible things to optics except in high plus powers with very precise base curves.

For the lenses I have worn (number 61, and 62 ordered this week) I have never found any hybrid lens to provide wider zones and less distortion than most  generic Free-form designs.  Although a few provide one or the other, none provide both.

The first question always to me, is what is your patients lifestyle needs?  The second question, what is the best lens for those needs?  You can answer the second until we have examined the first.

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## hlstavn

I have tried 2 Physio Drx versions and neither was close to the wide zones of my physio enhanced, the drx had a peanut sized reading zone so i have crossed those off. Good explanantion of the comfort vs physio design. Can you specify corridor length when ordering a physio?

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## Happylady

What about the regular Physio and Physio Short? I have both the Enhanced and the Short and while both are good I prefer the Short slightly. I like the high reading area and the intermediate area is fine.

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## sharpstick777

> I have tried 2 Physio Drx versions and neither was close to the wide zones of my physio enhanced, the drx had a peanut sized reading zone so i have crossed those off. Good explanantion of the comfort vs physio design. Can you specify corridor length when ordering a physio?


It took me 3 full weeks to get decent width in the DRx.  Its one of the slowest adapting lenses I have ever worn.

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## nclairmore

> It took me 3 full weeks to get decent width in the DRx.  Its one of the slowest adapting lenses I have ever worn.


I have had limited experience dispensing DRx because most of my patients experienced this same thing.  Even if they have the patience to get fully adapted, I don't hear the same positive reviews that I do with the Enhanced.

Your explanation of comfort vs physio was very helpful!

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## Jason H

If the enhanced line is (at least partially) a molded front surface, how can it have customized corridor lengths?

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## Better to see you

Please help! I have used Physio Enhanced for the last few years. I love them, however, I have moved to an lower income area competing big boxex & chains and it`s hard to move pt`s to that higher price. I have used regular physio with good success. My lens rep came by last week and said I should be using Physio Drx. I have never used physio Drx. I have a new pt. moving into the progressive world,Rx is -5.75 -1.00x 178 &-5.25 -1.00 x92 with a 1.25 add would the Drx be better?

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## Java99

Had rotten dispenses with the Physio DRx, which was odd, since at the same place the experiences were great with Physio Enhanced.  I think the Comfort Drx is better than anything else in the series though.  Great results for people who are moving from Ovation type lenses the chains supply.  Last year I put my father in an S and my mother in a Definity - his rx is roughly +1.00 -1.75 ou, her -5.00 -.50 ish ou, both +2.50 add.  This year I put them both in Comfort Drx and both prefer it.  I didn't tell them I was switching lenses on them.

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## Robert Martellaro

> If the enhanced line is (at least partially) a molded front surface, how can it have customized corridor lengths?


Jason,

Essilor starts with, and I'm guessing on the powers, a +.75 or +1.50 add semi-finished blank, surfacing the Rx and rest of the progressive optics on the back with a free-form generator. In some materials the Physio and Physio Short start with the same blank in a similar fashion as described above.

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## Happylady

I use the Enhanced and the regular Physio and Physio Short. I personally see no better through the Enhanced than through the Physio Short. I have compared at night also and the Enhanced is not better at all.

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## Robert Martellaro

> Please help! I have used Physio Enhanced for the last few years. I love them, however, I have moved to an lower income area competing big boxex & chains and it`s hard to move pt`s to that higher price. I have used regular physio with good success. My lens rep came by last week and said I should be using Physio Drx. I have never used physio Drx. I have a new pt. moving into the progressive world,Rx is -5.75 -1.00x 178 &-5.25 -1.00 x92 with a 1.25 add would the Drx be better?


I'm not familiar with the degree of optimizations with the DRx, and I haven't performed a blind test between these two designs. I have evaluated the Physio, and I doubt that the DRx would out perform the Physio in this Rx, unless the IPD is unusually wide or narrow. 

Check the axes- it's unusual to see WTR astigmatism and ATR in the same pair of eyes sans pathology. 




> Had rotten dispenses with the Physio DRx, which was odd, since at the same place the experiences were great with Physio Enhanced.  I think the Comfort Drx is better than anything else in the series though.  Great results for people who are moving from Ovation type lenses the chains supply.  Last year I put my father in an S and my mother in a Definity - his rx is roughly +1.00 -1.75 ou, her -5.00 -.50 ish ou, both +2.50 add.  This year I put them both in Comfort Drx and both prefer it.  I didn't tell them I was switching lenses on them.


That's somewhat surprising for your father's Rx. Same Rx for both pair?

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## Java99

> That's somewhat surprising for your father's Rx. Same Rx for both pair?


Old rx had a little less plus sphere, same cyl same add.  I was surprised as well, in my experience hyperopic presbyopes love the Definity.

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## Robert Martellaro

> Old rx had a little less plus sphere, same cyl same add.  I was surprised as well, in my experience hyperopic presbyopes love the Definity.


Thanks. Rx change will almost always trump lens design, so I wouldn't give up on the Definity, although the Zeiss INDV2 is at least as good, and will outperform the Essilor lenses when there are outlying Rx and/or POW parameters.

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## DanLiv

> The Enhanced version is a hybrid design (partially free-form), the DRx versions are 100% Free-form. The advantage of Free-form is not in just the accuracy, but to be able to control all the curves that link the distance and reading portions of the lens together both in and outside the intermediate corridor. Hybrid lenses have some or all of the add cast, and so these curves cannot be fully optimized.



I don't understand *why* you get more precision out of a full backside design.

Every point in the lens is a relationship between the front and back curve, and even "full" free form are tied to a fixed spherical front curve. You can't control all the curves, only the backside ones. Progressives aren't going to have anything near spherical curvatures and with free form the entire deviation from spherical must be produced on a single surface. If we know every progressive is going to be at least +0.75 add, why not start with blanks with at least that much of a design prepared? A digitally molded front side progressive can be just as precise as a digitally molded spherical blank. If every point on a front curve is known to 0.01D accuracy, software can precisely calculate every backside point to produce the optimal design. I don't see why a fixed spherical surface should be any less constraining than a fixed progressive surface.

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## sharpstick777

The fundamental issue with pre-cast blanks and adds is that they are dumb.  It doesn't know the RX that is going into it, it doesn't know the frame shape or size, it doesn't know what is going into the other eye, or the POW measurements.  With True 100% free-form all those become factors in a good design.  

As well, aligning two corrective surfaces becomes more tricky.  make two circles with your hands, and look through both at the same time in row.  Fine, you can see ok, but now walk around.  With dual surface designs you are aligning 3 things, the eye and two lenses.  With single surface designs you only have to align one lens and one eye.  It vastly reduces the chances of something going wrong.




> I don't understand *why* you get more precision out of a full backside design.
> 
> Every point in the lens is a relationship between the front and back curve, and even "full" free form are tied to a fixed spherical front curve. You can't control all the curves, only the backside ones. Progressives aren't going to have anything near spherical curvatures and with free form the entire deviation from spherical must be produced on a single surface. If we know every progressive is going to be at least +0.75 add, why not start with blanks with at least that much of a design prepared? A digitally molded front side progressive can be just as precise as a digitally molded spherical blank. If every point on a front curve is known to 0.01D accuracy, software can precisely calculate every backside point to produce the optimal design. I don't see why a fixed spherical surface should be any less constraining than a fixed progressive surface.

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## DanLiv

> The fundamental issue with pre-cast blanks and adds is that they are dumb.  It doesn't know the RX that is going into it, it doesn't know the frame shape or size, it doesn't know what is going into the other eye, or the POW measurements.  With True 100% free-form all those become factors in a good design.  
> 
> As well, aligning two corrective surfaces becomes more tricky.  make two circles with your hands, and look through both at the same time in row.  Fine, you can see ok, but now walk around.  With dual surface designs you are aligning 3 things, the eye and two lenses.  With single surface designs you only have to align one lens and one eye.  It vastly reduces the chances of something going wrong.


Got it, thanks!

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