Problems with optimized rx's?

[MakeOptics]

The comments about shape of design and lenticular astigmatism are way out there.

To address the lenticular astigmatism, marginal astigmatism and power error are effects of the lens system. Best form is designed to reduce/eliminate these lens errors. Corneal/lenticular astigmatism is a fuction of the eyes optics. As long as the eye is rotating behind the eyeglass lens a best form is going to attempt to provide stigmatic power in points across the lens surface so the clarity should remain the same throughout a wider portion of the lens.

A compensated prescription is attempting to provide a localized power in a tilted system compared to the untilted refractive power found during refraction. These formulas are fairly well documented and accepted.

Now with that background a compensated design is an attempt to merge best form and compensation in essence together. So rather than focusing on a localized power error the focus is on a wider portion of the lens compensated to provide clarity.

The poster may be talking about a compensated prescription instead of a compensated design, which is comparing apples to oranges. Thats why the message is giving me a headache, this thread isnt really discussing anything in particular just the frustration with the lack of understanding of what type of lens is being fit. Unfortunately without the particular lens design in question how can any reply be of any use.

[Robert Martellaro]

The position of astigmatism, corneal or lenticular, is critical when calculating powers for implants and contact lens, I don't see how its position signifcantly influences what happens on the spectacle plane.

Sharpstick,

I respect your substantial ophthalmic optics knowledge, and am thankful that you're sharing this knowledge. I'm just skeptical when claims are made that I don't understand. That doesn't mean I'm right though, of course!

My hat is always tipped to Robert...

B

My hat is tipped to you Barry, always.

[dash1]

The comments about shape of design and lenticular astigmatism are way out there.

To address the lenticular astigmatism, marginal astigmatism and power error are effects of the lens system. Best form is designed to reduce/eliminate these lens errors. Corneal/lenticular astigmatism is a fuction of the eyes optics. As long as the eye is rotating behind the eyeglass lens a best form is going to attempt to provide stigmatic power in points across the lens surface so the clarity should remain the same throughout a wider portion of the lens.

A compensated prescription is attempting to provide a localized power in a tilted system compared to the untilted refractive power found during refraction. These formulas are fairly well documented and accepted.

Now with that background a compensated design is an attempt to merge best form and compensation in essence together. So rather than focusing on a localized power error the focus is on a wider portion of the lens compensated to provide clarity.

The poster may be talking about a compensated prescription instead of a compensated design, which is comparing apples to oranges. Thats why the message is giving me a headache, this thread isnt really discussing anything in particular just the frustration with the lack of understanding of what type of lens is being fit. Unfortunately without the particular lens design in question how can any reply be of any use.

I am still trying to see how you are reading more into the post than other people responding are?? An optimized or compensated rx to me is any rx that has been altered from what was prescribed due to a computer saying it is needed. I don't have any problem understanding anything other than why you seem to only post what is not right with what people are saying? Seems like you have some kind of knowledge complex? Maybe if things that are below your limited comprehension give you a headache you should stick to responding only with people who have PHD's?? If all you have is information that is negative then don't post! I can tell that you don't have any information I need or want. JMHO

[Barry Santini]

RE: Lenticular astigmatism. Me thinks if the speculation about this as a possible origin of complaint with Compensated lenses may have less to do with the compensation and more to do with how FF lenses affect perceptual issues for these people. The origin of the astigmatism would dictate its power space, and therefore differentiate it in correction from from corneal.

Darryl?

B

[drk]

Not Darryl.

There is some confusion here, from the normally sharp Sharpstick. Bad, bad Sharpstick.

1. Corneal astigmatism vs. lenticular astigmatism should not matter. All astigmatism is some mixture of both.
2. Refraction engineers (new term I just coined) do this: if the subject says "more cyl, please" on the -1.00 DC, and then "less cyl, please" on the -1.25 DC, then what does subject really, really want? Maybe -1.12 DC. Maybe -1.08 DC. But definitely not -1.25 DC. So, we give less. It doesn't add up to much, at all.
3. Perception-schmerception notwithstanding, the person simply has to wear the glasses and let their visual system plasticity take over.

I have to agree with Robert and PhiHate.

[drk]

I wonder if part of the original problem is doctor taking high Rx measures with the patient's eyes too close to the phoropter, and then not trial framing to confirm accuracy. It is just one more thing to troublshoot.

I have the oh-so-standard AO-clone refractor "head" or "phoroptor". With tricked-out prismatic viewing of vertex distance, I will say. (Wish it were a lighted prismatic viewer, but let's not get too crazy.) If you "fully retract" or "flatten" the hair-pulling device, I mean, the headrest, then the vertex is about 13.75 mm. So, really, it's more an issue of "refracting long" in most cases, since no one likes gooky, foggy lenses and they push out the headrest.

[MakeOptics]

Thank you DrK for your objective digestion of my response. Sad to say the original poster seems to want to believe the misinformation given to him, confusing but understandable. The correct and acceptable response to the original poster is, "yeah you're right these manufacturers don't have a clue what they are doing." Sad really.

On another note I have a see through ruler I like to use with press on prism wedges that allows me to measure vertex distance from the front. I placed a sliver of 25 PD on the front and back of the ruler to create 50 PD total and then directly below it I placed the same with the bases in opposite directions to the ones above. The total difference is 100 PD, so when I bisect the pupils edge each mm that the pupil edge is displaced corresponds directly to the number of mm of vertex distance. Effective and low cost DIY optics.

[drk]

Cool. I'd like to see a photo of that.

[Wes]

I am still trying to see how you are reading more into the post than other people responding are?? An optimized or compensated rx to me is any rx that has been altered from what was prescribed due to a computer saying it is needed. Not exactly. See highlighted comments in PhiTrace's post below. Meister has quite a bit of information on Opticampus that goes into more detail. I can make a "compensated prescription" with a pencil and scratch paper. I cannot make a "compensated design" with a CRAY. I don't have any problem understanding anything other than why you seem to only post what is not right with what people are saying? Seems like you have some kind of knowledge complex? Maybe if things that are below your limited comprehension give you a headache you should stick to responding only with people who have PHD's?? If all you have is information that is negative then don't post! I can tell that you don't have any information I need or want. JMHO

Why are you upset that PhiTrace is reading more into the post than others? He is seeing things that others missed and you're upset at him??? Darryl Meister would see the same things. I see it too. Don't be so insulting and hostile to those offering information that you're unfamiliar with. Read the highlighted portions of the following:

The comments about shape of design and lenticular astigmatism are way out there.

To address the lenticular astigmatism, marginal astigmatism and power error are effects of the lens system. Best form is designed to reduce/eliminate these lens errors. Corneal/lenticular astigmatism is a fuction of the eyes optics. As long as the eye is rotating behind the eyeglass lens a best form is going to attempt to provide stigmatic power in points across the lens surface so the clarity should remain the same throughout a wider portion of the lens.

A compensated prescription is attempting to provide a localized power in a tilted system compared to the untilted refractive power found during refraction. These formulas are fairly well documented and accepted.

Now with that background a compensated design is an attempt to merge best form and compensation in essence together. So rather than focusing on a localized power error the focus is on a wider portion of the lens compensated to provide clarity.

The poster may be talking about a compensated prescription instead of a compensated design, which is comparing apples to oranges. Thats why the message is giving me a headache, this thread isnt really discussing anything in particular just the frustration with the lack of understanding of what type of lens is being fit. Unfortunately without the particular lens design in question how can any reply be of any use.

[braheem24]

Cool. I'd like to see a photo of that.

http://www.optiboard.com/forums/show...ght=rodenstock

[Darryl Meister]

Why are you upset that PhiTrace is reading more into the post than others? He is seeing things that others missed and you're upset at him??? Darryl Meister would see the same things.

I would have, but PhiTrace has already summed up most of the issues nicely.

Lenticular astigmatism is actually fairly common (Javal's rule, for instance, assumes 0.50 DC of against-the-rule astigmatism, although I understand that this is an overestimate). This astigmatism simply interacts with any corneal astigmatism or astigmatism due to other optical factors, resulting in the final ocular refraction. It doesn't really matter to the spectacle lens what the source of the ocular astigmatism is, as DRK pointed out earlier.

That said, astigmatism due to certain optical factors that also result in other "high-order" ocular aberrations may produce certain optical interactions with the surface astigmatism of the progressive lens, particularly at larger pupil sizes. For instance, tilt of the crystalline lens can introduce both astigmatism due to lens tilt as well as high-order aberrations that can interact with the coma and trefoil of a progressive lens.

But current spectacle lenses cannot address this, anyway. For the matter, even the process of accommodation can result in small changes in astigmatism. In any event, the problems experienced by the patient are probably due to something other than a properly compensated prescription. Now, whether the prescription has been properly compensated or not is another story. This relies both on accurate manifest refraction, an accurate measurement of the position of wear in a properly adjusted frame, and accurate software calculations.

And, as PhiTrace already stated, compensation for the position of wear specifically applies to only one point in the center of the distance zone for progressive lenses that have not actually been optically optimized for that position of wear. If the lens has not been optically optimized for the position of wear, the patient is really only getting the ideal or "compensated" prescription at one point. In any event, consistent issues with a particular lens design are definitely worth investigating.

The origin of the astigmatism would dictate its power space, and therefore differentiate it in correction from from corneal.

This is actually a technical subtlety that many people aren't aware of, since it deals with the nature of the eye as a "thick" optical system. As a consequence of this fact, adding a purely spherical power to the eye may actually result in a small amount of cylinder in some cases, and vice versa. See, for instance, "Subjective refraction: the mechanism underlying the routine" by Harris in Ophthal. Physiol. Opt. 2007, 27.

That said, once the refractive error has been neutralized by a corrective lens power at a particular reference plane, such as the vertex distance plane of the eye, I believe that these optical subtleties cease to matter. A compensated prescription simply seeks to provide the same corrective lens power effect at that same reference plane, whenever the orientation of the spectacle lens has been changed. So I don't think it should really matter much in this particular context.

Best regards,
Darryl

[Darryl Meister]

Not Darryl

Send me an application and a money order for $500, and you can rent the screen name for an entire weekend!

Best regards,
Darryl

[Barry Santini]

Thank you Darryl, Phi Trace, Sharpstick and drk. I learn from all!

Barry

[dash1]

Why are you upset that PhiTrace is reading more into the post than others? He is seeing things that others missed and you're upset at him??? Darryl Meister would see the same things. I see it too. Don't be so insulting and hostile to those offering information that you're unfamiliar with. Read the highlighted portions of the following:

I'm not saying that he doesn't know what he is talking about because I can see he has a great deal of knowledge, it's how it was shared that is my issue. If he had originally asked for me to go into more detail about instead of the way he stated it I wouldn't have thought anything of it. The fact that there is a large gap in knowledge in opticians nationwide speaks for itself. There were several people on here who answered the question which tells me they read it as I wrote it. I think the problem is PHITRACE was reading more into the science of optics than I was asking. I was talking about a SV script in autoII with NO POW given and with wrap Eyewear that the lab alters the prescription because their program says to do it. I am trying to understand why the programs are always weakining the myopic scripts I receive? I'm sorry to have seemed a bit snippy but I have dealt with people before that feel since they went to school for 8yrs and have a DR or PHD before their name that they can speak to you in any manner they choose! I have raised 3 kid's and been performing my job for 20 years with a large following of pt's that like the work I do so I don't think I deserve anything but the same courtesy that I give to others. Phitrace, I am sorry if I took what you said out of context and I do appreciate the information given on this forum.

[drk]

P.S. Barry: nice article on FFSV in 20/20.

[Barry Santini]

P.S. Barry: nice article on FFSV in 20/20.

Thanks, drk.

I've decided to add to this post an excerpt from a Yelp review I rec'd recently for personalized, bevel-matched, POW'd FF SV 1.6 index (approx -5.00). I'm not tooting my horn, but this example was actually someone who brought in an online sourced IC Berlin, and I agreed to put lenses into it. I think it's illustrative of how blanket/sweeping statement about servicing online clients may be short sighted. Whatever I didn't "make" on the frame was returned manifold in this over-the-top review.

If you want to see the entire review, look up LI Opticians, Seaford, NY on Yelp.

"Barry went through extra effort to make personalized lenses work for my deep set eyes in my wrap frames by calling industry standards people to help compensate through other atypical adjustments. Impressively, through his knowledge & personal contacts, he made the personalized lens curvature work for my extremely deep-set eyes and non-flat frames with spectacular results.

While I was impressed and happy to see better and move my eyes around, the difference really struck me later that night when I laid down in bed to watch some TV. The positioning gave me a very broad perspective of something I was intimately familiar with looking at, my 28' wide room. For the first time in my life I could see my room laid out like a panorama with stunning clarity. Because my contacts don't have correction for my astigmatism but my glasses do, I was used to glasses for clarity, but preferred contacts overall because of the peripheral vision without realizing why. No more. My glasses with personalized lenses offer both & win the contest with contacts hands down. No more the dry eyes or extra effort, especially when I'm tired. After this, I can't go back to non-personalized lenses where I have to turn my head to see what I should be seeing anyway.

I'm recommending Long Island Opticians to family & friends due the wonderful experience and extra mile Barry went to make everything work for me"

B

[Wes]

I'm not saying that he doesn't know what he is talking about because I can see he has a great deal of knowledge, it's how it was shared that is my issue. If he had originally asked for me to go into more detail about instead of the way he stated it I wouldn't have thought anything of it. The fact that there is a large gap in knowledge in opticians nationwide speaks for itself. There were several people on here who answered the question which tells me they read it as I wrote it. I think the problem is PHITRACE was reading more into the science of optics than I was asking. I was talking about a SV script in autoII with NO POW given and with wrap Eyewear that the lab alters the prescription because their program says to do it. I am trying to understand why the programs are always weakining the myopic scripts I receive? I'm sorry to have seemed a bit snippy but I have dealt with people before that feel since they went to school for 8yrs and have a DR or PHD before their name that they can speak to you in any manner they choose! I have raised 3 kid's and been performing my job for 20 years with a large following of pt's that like the work I do so I don't think I deserve anything but the same courtesy that I give to others. Phitrace, I am sorry if I took what you said out of context and I do appreciate the information given on this forum.

Sir or Ma'am, I would like to direct you to Martin's formula for tilt/wrap. Basically the following happens:
Tilt/wrap a minus sphere lens at 90, you induce excess sph power everywhere, and induce - cyl power at axis 90. to compensate for this, you reduce the sph power and induce a cross cyl of the same value, which is why the compensated axis will be at 180 to offset the induced cyl according to cross curve theory.
Tilt/wrap a plus sphere at 90, you induce excess sphere power everywhere, and induce + cyl power at 90. While you still reduce the sph power, this is somewhat different than the previous example, but if you transpose the resulting + cyl effective rx, you realize that a plus lens results in - cyl rx being at 180 which means according to cross curve theory, the corrected rx will have a cyl at 90.
Next, try tilting the lens at the 180 meridian for panto, and see what further happens.
Also, if you order compensated lenses without providing tilt and wrap data, you get lenses made with DEFAULT #s. If your patients' information is not in accordance with the default info, they will not be happy.
All of this is a bit of a moot point if we are not talking about a compensated rx, but a compensated design, let alone a "so-called compensated rx with no parameters introduced".

All of this aside, there's the possibility that the patient doesn't like the half diopter or so of base out prism induced by wrap glasses. Vertically tilted glasses can have similar issues. See Meister's Spectacle Optics program.

[Robert Martellaro]

Wes, thanks for answering at least part of the newbie's question in a professional way. No one wants to be told that their question is of such poor quality that it gives them a headache.

To the OP: Get a thicker skin, and don't get in a pissing match with the master pisser- you won't win that one.

WRT non-adapts and advanced surface designs and optimized optics- I'm not having problems, but I'm using good lenses (Zeiss and Shamir), I don't use the default POW values, the lenses are optimally positioned, and I don't put twenty degrees of wrap on a minus five with an eight base.