Wavefront

[drk]

I question the value of wavefront in spectacle and CL applications. I just don't think the positioning ("registration") of a spectacle frame or a CL is going to be too variable to make the concept work.

This is assuming, of course, that spectacle and contact lenses can be manufactured to such tight tolerances in the first place.

Any thoughts?

[rinselberg]

One of the questions that you raise is the on-eye stability limitations of spectacle and contact lenses: How could wavefront corrected spectacle and contact lenses be practical when we consider the way that a spectacle frame bends or jiggles around slightly as it is worn, or the way that a contact lens drifts or rotates a little in front of the eye?

Why not make an inquiry, as an ECP on behalf of OptiBoard, to one of the companies that has ventured to try and bring these projects into the marketplace? Even if you don't agree with their response, it might be interesting to see what they have to say about this. I could make the inquiry myself, but since I am not an ECP, your inquiry might carry more weight.

Ophthonix is developing wavefront spectacles and contact lenses:
http://www.ophthonix.com/

[CDOT]

I just saw rinselbergs post and went to the link, it sounds very intriguing. Does anyone have any personal experience with this system?

[rinselberg]

I have not inquired about the accuracy or precision of the Ophthonix lens manufacturing process, which is one of the issues that "drk" raised at the beginning of this thread. I would like to forward the discussion, however, by observing that the Ophthonix lens manufacturing process is a complete departure from anything that has ever been discussed on the OptiBoard website:

A proprietary epoxy gel layered between two optical material surfaces is exposed to a specially created ultraviolet laser that causes the material to "cure" in a pattern which creates the desired refractive profile.

The refractive patterns can be adjusted to correct for low order and high order aberrations such as coma, trefoil, spherical aberration, tetrafoil, distortion and astigmatism.

In other words, the Ophthonix lens is actually an array of a large number (1000 --?) of "pixel-sized" micro-lenses, each with an independent laser-generated index of refraction: So the index of refraction varies from point to point over the entire surface of the lens.

For the complete press release:
http://www.ophthonix.com/news/press_...ed.asp?prID=73

The website provides a number of E-mail addresses on the CONTACT page, including one for "General Information" -- which would seem to be the best E-mail contact to use for technical questions.

[chip anderson]

Rieselburg: Sounds like plastic lens molded between two glass surfaces and cured with UV Laser (which a lot of lenses are). Wouldn't really look for variable indicees here (unless the curing process is not complete, and then it would be irregular and uncontrolable.

Chip

[rinselberg]

Hello Chip,

I appreciate your interest!

After digging some more into the Ophthonix press releases, I can tell you for sure that my understanding of their lens manufacturing process, as I described it in my previous post, is not far off. Each individual point or "pixel" on the surface of the lens is UV-cured to provide an independently variable index of refraction.

... the process utilizes the low and high order refractive measurements taken by the Ophthonix Z-View™ Aberrometer and allows them to be programmed into the company's proprietary optical material. The material is sandwiched between two lens surfaces and then radiation cured to different indexes of refraction.

http://www.ophthonix.com/news/press_...ed.asp?prID=80

This sixth patent protects a novel manufacturing procedure that literally builds lenses pixel by pixel to specifically match a patient's optical finger print - an individual's unique refractive requirements. Using the protected Ophthonix process, a variety of polymer droplets are precisely deposited at pre-selected locations by a micro jet device, creating multiple composition layers of the lens. The layers cure into varying refractive properties that match the patient's specific optical needs.

http://www.ophthonix.com/news/press_...ed.asp?prID=62

[drk]

Nice work, Rinselberg.

[Jedi]

We are all familiar with our spectacle tolerances and how patients react to them. What is the point of super accurate lenses, if the client is not going to see a remarkable difference (have a look at the PDF's on their site). It sounds like they are trying to cash in on the "wavefront" buzz.
Also, now keep in mind I haven't had the opportunity to scrutinize the entire site, but don't most CL's rotate to some degree therefore negating any benefit from specialized "wavefront" CL's.

[rinselberg]

"drk" and Jedi raised the question of on-eye stability requirements for wavefront corrected lenses.

After reviewing the entire Ophthonix website, these are the only relevant statements that I could find:

On-eye stability requirements for wavefront contact lenses:
-- Translation (movement and centration) up to 0.5 mm.
-- Rotation up to plus or minus 10 degrees.

"Any of today's soft torics meet these criteria."
http://www.ophthonix.com/reviews/pdf/wavefront_cl.pdf
(Page 20.)

"Wavefront spectacle lenses can be used with any frame chosen by the patient."
http://www.ophthonix.com/technology/izon-glasses.asp

[jherman]

Depending on the rate of change in index, this type of technology could have other applications with lens design.

I think it cool enough to see what the possibilities are.

Are there any testimonials?

Andreas said he was starting with East, and West coast first.

[rinselberg]

This is a little off-topic, I guess, but thinking about the on-eye stability of spectacle lenses reminded me of some very unique frames that I found on the Internet some time ago: The Staffan Preutz "SP" frames. These are rimless frames (which I believe are available in both the U.S. and Europe) that do not have conventional temples. They have short temples, about half the length of the usual temple piece, and use a soft pad that clamps directly onto the side of the head, well forward of the ear, via gentle pressure from the springiness of the frame.



This is only speculation, but perhaps this very unique frame design offers more in the way of on-eye stability than more conventional frames.

Personally, I think they are ugly, but that of course, is just a matter of aesthetics.

The Staffan Preutz (USA) website:
http://www.staffanpreutz.com/USA/Preutzsecond.htm

Staffan Preutz is the eyewear genius who plans to launch a new collection of eyewear for women to wear at funerals:

Polaris Optic AB Sweden to launch "Funeral" collection

http://www.optiboard.com/forums/showthread.php?t=13560

As one of my favorite OptiBoarders (ksquared) observed at the very end of that thread:

This is just the kind of “thinking inside the box” the optical industry needs to do in order to stay profitable.

[rinselberg]

Come to think of it, I just remembered another frame design that (perhaps) would improve the on-eye stability of spectacle lenses:


"Step one ..."


"gorgeous example of a piercing-mounted set of eyeglasses"

http://www.bmezine.com/news/pubring/20041214.html

When frame and nose become one

[spartus]

I would NOT want to slip with the screwdriver on that pair.

[rinselberg]

Are there any testimonials?

They provide a link (below) to a recent newspaper article.

The company produces about 60 pairs of custom-made eyeglasses each day, and is scaling up to manufacture more.

Phil Smith, a Hillcrest optometrist, said he bought an Aberrometer in January because the technology is "cutting-edge."

"I have a number of patients that complain that their night vision is not good with glasses, or it's not crisp, and we just can't put our finger on it," Smith said. "But we're starting to learn that a lot of these complaints are due to higher order aberrations that can't be corrected with ordinary glasses or contacts.

"I think Ophthonix's technology has the potential to solve patient problems, to have a significant impact," Smith said. "That's my hope, and I want to be there when it happens."

That's the only personal testimonial that I see there, with their clinical studies and technical papers.

It's a well written newspaper article that provides a good, fast summary of everything on the Ophthonix website.

http://www.signonsandiego.com/news/b...-1b25lens.html

[AEOC]

I had the instrument in the office for a couple days and made up about 7 pairs. All 7 were for patients with clinically significant amounts of high order aberration (according to the aberrometer). Response has been good for 4 of the seven. One has not been dispensed, and the other 2 were for post-lasik patients, one that is still in the process of healing and one that had less than optimal results with BCVA of 20/40 with conventional spectacle lenses. Patients were impressed with the technology and interested in hearing about lenses that can potentially provide them with better vision; I'm just not sure if I'm ready to totally jump on board. The autorefraction the aberrometer comes out with is very accurate. One down side is that you don't get K readings which we currently get from our autorefractor.

I might be more willing to become an early adopter if we weren't a new practice and I hadn't just signed a lease for a fundus camera...

[rinselberg]

A study by James S. McLellan, PhD, and colleagues found that higher-order aberrations may exist to offset chromatic aberrations.

“Researchers found that higher-order aberrations balance out chromatic aberrations so that we don’t see chromatic rainbows around objects or light,” Dr. Holladay said.

Chroma or “rainbows” present when white light is prismatically dispersed. The normal human eye has approximately 1.5 D of clinical chromatic aberration, between red and blue. However, the negative effects of chroma are typically not experienced because higher-order aberrations, ocular imperfections that are traditionally thought to cause vision problems, cancel out the chromatic blur.

“It’s important for clinicians and researchers to understand that removing higher-order aberrations will cause chromatic aberrations to become more significant,” Dr. Holladay said.

Understanding the eye’s optics is key to assessing, improving quality of vision
OCULAR SURGERY NEWS 4/15/2005
Nicole Nader
http://www.osnsupersite.com/default.asp?ID=10283

It would be interesting to see what Ophthonix might have to say about this.

I may put this issue before them as a potential wavefront correction patient some day.

Ophthonix home page
http://www.ophthonix.com

[drk]

It does not seem intuitive at all that chromatic abberation can be mitigated by other types of HOA. I just don't get that one.

[rinselberg]

It does not seem intuitive at all that chromatic abberation can be mitigated by other types of HOA. I just don't get that one.

The idea goes back to a letter that appeared in the journal Nature in 2002, under the title Imperfect optics may be the eye's defence against chromatic blur.

Here is an abstract:

The optics of the eye cause different wavelengths of light to be differentially focused at the retina. This phenomenon is due to longitudinal chromatic aberration, a wavelength-dependent change in refractive power. Retinal image quality may consequently vary for the different classes of cone photoreceptors, cells tuned to absorb bands of different wavelengths. For instance, it has been assumed that when the eye is focused for mid-spectral wavelengths near the peak sensitivities of long- (L) and middle- (M) wavelength-sensitive cones, short-wavelength (bluish) light is so blurred that it cannot contribute to and may even impair spatial vision. These optical effects have been proposed to explain the function of the macular pigment, which selectively absorbs short-wavelength light, and the sparsity of short-wavelength-sensitive (S) cones. However, such explanations have ignored the effect of monochromatic wave aberrations present in real eyes. Here we show that, when these effects are taken into account, short wavelengths are not as blurred as previously thought, that the potential image quality for S cones is comparable to that for L and M cones, and that macular pigment has no significant function in improving the retinal image.

Abstract online at National Center for Biotechnology Information:
http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract

Complete three-page report in Nature
http://www.vision.io.csic.es/papers_..._chromatic.pdf

I also attached the complete article text below, in case it doesn't download directly from the Web.

[coda]

Ron, you never cease to impress me. -Coda

[Optician]

Actually, I've been doing a bit of reading on the subject of wavefront lately (yes, I lead a sad existence- even my leisure reading tends to be optically oriented).

I'll post some links I've found, but- cutting to the chase- it seems to me that the end advantages of wavefront applications are going to be primarily related to improved acuity in low lighting situations (due to better contrast sensitivity). Most of the higher order aberrations become dramatic only in the presence of larger sized lens stops (in the case of the eye, this is the pupil). Of course, pupil size increases in low lighting situations.

In one interesting LASIK study (follow the journalofvision link), the wavefront guided procedure did reduce higher order aberrations in the eye- for a while. Some months later, measurements indicated that the aberrations had mostly returned, and the only visual benefit that was sustained to some degree was a minimal increase in contrast sensitivity.

I think wavefront will make an impact on certain opthalmic applications- perhaps in way that is somewhat less obvious than measuring eyes with aberrometers and customizing lenses to the individual's reading.
http://lo.um.es/publications/PDFs_ma...ve_OVS2003.pdf
http://www.optics.arizona.edu/jcwyan...s/Zernikes.pdf
http://www.optometry.co.uk/files/260...ev20030124.pdf
http://journalofvision.org/4/4/2/article.aspx

[QDO1]

er.. what happens when the patient looks off axis (spectacle lens)?

[rinselberg]

er.. what happens when the patient looks off axis (spectacle lens)?

Don't know. That is the question that "drk" raised at the very top of this thread. It would be an interesting question to put to Ophthonix. I just sent a few technical questions there myself, by E-mail, but I don't think they are going to respond. It's been too long since I E-mailed my questions.

Ophthonix website:
http://www.ophthonix.com

Ophthonix E-mail address:
info.ophthonix.com

[QDO1]

Wave front is usually used in laser eye surgery, and with great sucsess over regular laser surgery. That is a form of optics I understand.

I can't comprehend using it for spectacles or contact lenses - either the lens moves on the eye, or the eye moves infront of the lens. I am open to new ideas, perhaps im not educated enough

[Myoptic33]

I too heard of this and it shows lots of promise. Some think its a gimmic, others sware by it. Does anyone know how much the glasses lenses would cost? the contact lenses? I stand to benefit from this and possibilly achieve 20/20 vision. Right now I get 20/30 with my -5 glasses due to high order abberations. One OD said I should achieve 20/20 with RGP contacts, if not the problem is not just my HOA's

[rinselberg]

re: Myoptic33 (above)

"Click" on the underlined names below to go directly to their Websites:

Ophthonix currently offers SV (single vision) iZon Wavefront-Guided Spectacle Lenses. I do not know what their status might be on attempts to transfer the same technology to the domain of PAL (progressive addition) spectacle lenses.

Optical Connection is partnered with Ophthonix in an effort to bring iZon by Definition FRP (wavefront corrected) soft contact lenses to market. I do not know their current status.

SynergEyes has been testing the SynergEyes W wavefront corrected contact lens. I do not know their current status.