"WOW! This is, like...*freaky-clear*!"

[Pete Hanlin]

Ahem...here, I disgree with you.
First, I hope that cold (or whatever is causing you to clear your throat) clears up... :)

However, binocularly, 0.25D can make a *significant* difference to a person, particularly with respect to accomodative/binocular balance.
I agree, which is why most refractions end with a binocular assessment. BTW, the improvement of binocular vision (which is also affected by design symmetry) is the key design feature of Varilux Panamic.

Even 0.12D can be a reasonable amount to discriminate in binocular balance testing.
Perhaps for a few individuals- generally, 0.25D should work quite well for the majority of patients assuming binocular balance is respected.

Although the standard duo-chrome test equals a 0.50D difference between the red and green... Remember, the duo-chrome test is as much a test of focus as it is of contrast, and contrast sensitivity/discrimination is many times more sensitive in people than straight resolution/focus.
I'm a big fan of the duochrome test- I teach the theory and practice of it in two of the courses I teach. IMO, the duochrome test is underutilized and I believe its inclusion at the end of a refraction would likely cut down on rechecks. As for contrast, we conducted several studies on contrast sensitivity function which underscored the role of CSF in preparation for the Varilux Physio launch. Measurement of visual acuity with a Snellen chart tests only a small fraction of a patient's scope of vision- CSF is a major driver of a patient's quality of vision (anyone who has rechecked a patient complaining of "vision that isn't sharp enough" only to find s/he is able to see 20/20 may be dealing with a case of compromised CSF).

Think of it this way: standard acuity/resolution testing is to binocular balance testing as standard threasholds of acuity are to Vernier Acuity, wherein a comparison is being made, and the thresholds of discrimination are many (up to 6x) times greater because of the number of retinal cells being fired (like a line vs. a point) Human beings vision systems are much more sensitive to making a sensory comparisons.
Using contrast sensitivity function as a common point of reference, to back up a claim of "6x resolution," you would have to be increasing the eye's "cut-off frequency." (Cut-off frequency is usually 40 c/d for a normal human eye- that is, imagine a pattern of black and white lines- a human eye is normally capable of seeing 40 cycles between black and white over the course of a degree.) I'm quite sure refracting in 0.125 diopter increments- or even 0.01 diopter increments- will fail to improve the cut-off frequency (maximum resolution) of the eye by 6x.

Actually drk, I didn't mean to imply that I get tooexcited about 0.01D accuracy, either. And 0.12D precision is good ebough for standard refraction protocol, IMHO. I think techs are particularly undertrained with binocular refraction techniques.
Well, if we're talking about 0.12D precision, then digital surfacing becomes immaterial- because we can order traditional products in 0.12D increments with a fair degree of accuracy. BTW, I agree that binocular refraction is underutilized (by all refractionists, not just techs).

In the end, I think we're agreeing far more than not- my main concern surrounds "fuzzy marketing" claims which have been made surrounding the "benefits" of 0.01D accuracy by some manufacturers of digitally surfaced products.

Great discussion!

[Barry Santini]

Pete, I just want to clarify that I wasn't trying to further or substantiate a claim of 6x greater resolution with my Vernier analogy.

Thanks for your great repsonses!

Barry

[Pete Hanlin]

Pete, I just want to clarify that I wasn't trying to further or substantiate a claim of 6x greater resolution with my Vernier analogy.
Thanks for the clarification- nice to have an intelligent discussion of lens technologies!

Granted, I like the concept of individualized SV lenses for the atoricity and base curve provision, but I don't get too excited about wavefront or 0.01 D tolerances.
drk- I agree, it makes sense to apply atoricity to a digitally surfaced SV product (or for that matter, to any DS PAL product). I've actually been surprised to find a lack of atoricity in some of the DS PALs we've evaluated- seems like atoricity would be a no-brainer since DS gives the designer the capability. Also, I think it needs to be better understood that atoricity is simply reducing marginal astigmatism and sphere error. While that's great, it probably only produces noticeable benefit to prescriptions in the outlying areas of the base curve chart.

There are two seperate aspects to wavefront correction. Without a doubt, PALs have aberrations (primarily coma, some trefoil) which can be "cleaned up." Of course, that's the concept behind Varilux Physio- correction for distance, near, intermediate without adding additional HOAs to the visual system. We can measure the gains in CSF on actual patients (up to 30%, there's a poster on the study that has been peer reviewed and presented at several conferences).

I'm dubious regarding the ability of a spectacle lens to "resolve" higher order aberrations within the eye itself (Dr. Thibos, at Indiana Univ. College of Optometry does a nice presentation explaining why alignment issues prohibit the correction of HOAs with spectacle lenses).

Most of all, I've becomed concerned over the past year with all the claims being made about DS products- especially given the lack of process control I've noticed in some DS production. I remember the early days of AR produced some rather, um- let's say "questionable" quality- and as a result, many consumers and eye care practitioners are only now coming back to AR. It would be a shame to repeat the same error with digitally surfaced products. They can be great- but both the design and the process have to be there, or the finished product can actually be worse than the traditional products we've successfully used for decades (many of which are pretty darn good products).

[sharpstick777]

Have you tried Nulux, Sharpstick? I think you might be pleasantly surprised. Nulux ep is HOYA's Bi-Aspheric Single Vision Lens design using free form technology. Nulux ep delivers clear vision edge to edge, calculated visual acuity at every point on the lens, and it's visually optimized for all powers. It's a great lens and Yep...I work for Hoya. :)

I did try Nulux and yes its good. My Hoya rep told me though the Nulux in the US in non-Atoric, even though Europe and Asia get an Atoric version.

Thanks,
Sharpstick

[sharpstick777]

Its pretty amazing, and while I do like it, I cant really say if the improvement is enough to warrant what a customer would pay for it.

Scrumblydumpus,
the prices I am paying for SV Auto II are equal (within $2) to regular Ashperics in Trivex, 1.60 and 1.67. Stnd Poly Aspheric is less though but I use Resolutions Poly Atoric.

PM for the lab I use.

Sharpstick

[sharpstick777]

Another benifit of Digital Processed lenses is that they can made off center, that way we can get cut-out on much larger frames, or in some cases use smaller blanks (and save a dime or two).

I hate getting that phone call from the lab telling me the blank size has dropped to 80mm and a job doesn't cut out now.

Sharpstick

[Oedema]

I wish my patients were even sensitive to a 0.50 D increment...:hammer:

[Barry Santini]

As with my own Hoya IDs, My NuLux EP did not provide the promised vision benefit/performance.

And I do not know why...

Barry

And from a later post in the thread, *now* I do: I wear a 1.50Dcyl, so if USA Nu-LUX EPs are really not corrected for atoricity, this would explain my lack of wow with these lenses.

barry

[Barry Santini]

Also, I think it needs to be better understood that atoricity is simply reducing marginal astigmatism and sphere error. While that's great, it probably only produces noticeable benefit to prescriptions in the outlying areas of the base curve chart.

Pete, you are referring to progressives here, yes? I wouldn't want the SV class of DS atorics (like Essilor 360) to get the heave ho until the cylinder powers went as high as you suggest the "outlying" areas of the base curve chart for progressive would take you.

Another perspective -

Why do so many of refractionsists seem to feel that "vetting" the vision value of new (different) exam findings is one of their top responsibilities? Within this discussion, it appears that we ECPs are acting inconsisitently:

1. On one hand, discussing/promoting the benefit of better vision through newer (more expensive) lens technology. On the other, often playing down the "need" for small Rx changes. I ask: "Which is more significant or beneficial?"

2. On one hand, saying (as Pete has) that Snellen acuity is insufficiently robust enough to fully describe what a person sees as acceptably sharp vision, yet on the other, saying that small amounts of un- or under-corrected sphere or cylinder are OK, since "I see 20/20 without wearing this Rx?"

Personal anecdote:
I continue to maintain that we all hide an almost universal negagtivity about eyewear, and the cost/value of the same. This really hit home to me last night, as I was leaving my orchestra rehearsal:

Several girls: "Wow, I can't wait to get back to the new Citifield Stadium (the new home of the Mets)." And then goes on to excitedly describe all the new convenience features and food offerings. The other sports-fan girls chime in and agree.

And I'm thinking: "Wow, I know how much tickets and the extras cost for going to just *one* game. I wonder why they chearfully all accept this amount of money as "ok", but less than 1/4 of this paid for better lens or frame technology often is not."

So, ECPs, I ask the following challenge question: Do we all agree on the value of what we do and can do , or not?

Barry

[Pete Hanlin]

Why do so many of refractionsists seem to feel that "vetting" the vision value of new (different) exam findings is one of their top responsibilities?
I think some eye care practitioners (Optometrists & Opticians), with honorable intentions, attempt to "protect the patient's wallet." Especially in the case of Opticians (based on my experience both as one and in managing them), I think there is definitely a thought process that goes something like this: "Man, I sure wouldn't spend $xxx for this or that feature on my own eyewear- I just don't think its worth it!"

I think this mindset springs from a number of factors. First, the average Optician may not be making much more than $25-30k/year, so a certain level of personal frugality (which is an admirable trait) is probably present. Second, everyone (including Opticians) is not a "visualphile." Think of an audiophile- someone who is very discerning with their speakers, music, etc. That person will spend $1,000s to obtain better equipment to fuel their passion for better sound- even if they do not have a high level of income. Same thing with a wine connoisseur- s/he will spend $300 for a bottle of wine for the experience of tasting it. So "visualphiles" (to me) are people who are very discerning visually- they CAN see the difference in technologies and they are willing to spend whatever it takes to see well- regardless of income. Personally, I do not happen to be an audiophile, a wine connoisseur, or even a visualphile (but my father is definitely a visualphile). My passion is automobiles- I'll spend more for a certain tire, certain engine, and even a certain type of gasoline... but that's just where my discrimination lies.

So, to your question...
Pete, you are referring to progressives here, yes? I wouldn't want the SV class of DS atorics (like Essilor 360) to get the heave ho until the cylinder powers went as high as you suggest the "outlying" areas of the base curve chart for progressive would take you.
Generally speaking, analysis of various prescriptions, aberration levels, and human vision indicates that ANY patient with >1.50 cylinder should notice discernable improvement with atoricity. Obviously, the visualphile (who- as I've mentioned- tends to be the "engineer" type, but I've met them from all walks of life) may see a benefit at any level of Rx.

To your point, the practitioner shouldn't pre-judge who is and isn't a visualphile. Just because the practitioner may not choose to spend the money on a particular technology, let the patient make the decision for him/herself! Only one caveat would I suggest- make sure the technology is actually REAL. Ask for the proof behind the claims (i.e., if a manufacturer claims a product is X, Y, or Z, it is reasonable to expect there should be some clinical proof that X, Y, or Z exists and can be discerned by actual human subjects).

PS- Now I remember why I quit posting on Optiboard so often- I tend to ramble on too long... sorry for the length of the post! :p

[Barry Santini]

Pete:

Great posts, don't stop!

IMHO, even 0.75 Cyl people "see" a significant difference with atoric FF SV. And I wouldn't refer to them a visualphiles, either.

However, and more to your points: No wine, music or car engine, et.c can so dramatically impact *anyone's* life as much as the participants in an auto accident. For this reason, above all others, Every ECP, IMHO, should *always* be recommending the absolute best vision for driving, and not just based on DMV acuity threshold "needs".

FWIW

Barry

PS - Pete, a Q: Do you wear your -0.50/-0.25 Rx for night driving?

[Pete Hanlin]

IMHO, even 0.75 Cyl people "see" a significant difference with atoric FF SV. And I wouldn't refer to them a visualphiles, either.
I'm sure a good % of folks with 0.75 cylinder may see advantages of atoric lenses- didn't mean to suggest they would not. My intention is to note once we get into the 1.50 cyl range, the recommendation of an atoric product (like the Autograph SV or Essilor 360 or Hoyas bi-aspheric) should be automatic. Even the most hesitant practitioner can confidently recommend the products knowing the patient has an almost 100% chance of seeing improvement.

Its kind of like the 1.00 cyl threshhold for toric CLs. At 1.00, nearly all patients will prefer a toric to a spherical equivalent, but I'm sure there are a good % of patients below 1.00 cyl who could appreciate a difference as well.

PS - Pete, a Q: Do you wear your -0.50/-0.25 Rx for night driving?
I do keep eyewear in the car for night driving (although I do not always use them). To be honest, the lenses in my "driving glasses" are from Ophthonix- and I do notice a bit less starbursting with them on (of course, I've also tried standard spherical SV lenses, and have noticed the identical effect). I try to experiment with as many products as I can, and I've not noticed any SV solution that provides significant improvement over another (but keep in mind I am somewhat indiscriminate with my vision... I'm an "easy patient"). I am 7 years post-LASIK, and I do have a certain amount of spherical aberration in my eyes. However, slight levels of starbursting at night are a small trade-off for a drop in Rx from my original -4.75 Rx!

Most individuals become slightly myopic while driving at night (or doing anything in scotopic conditions). In a dark environment, the eye interprets the darkness as having a depth of 10-15' or so, so the visual system actually accommodates ever so slightly (as a result, the refractive state of the eye requires from -0.25 to -0.50 additional minus power).

That brings me to fad product that just really causes me to seethe- namely, yellow tinted "night driving" lenses. Basically, placing ANY tint in front of the eye will reduce contrast sensitivity (because less light is making it to the retina). Anyone who could theoretically benefit from a yellow tint (e.g., someone with advancing cataracts) probably shouldn't be driving at night anyway. I would discourage practitioners from prescribing any kind of tinted lens for night driving (at least in the Dallas / Ft. Worth area :^).

Dang- another rambling post! :o

[Barry Santini]

Sorry that I inspire you to "ramble on", Pete, but it's good stuff!

BTW, there appears to be, from my perspective, quite a bit of possible latent "eyewear hate" in your statement about your pre-op, pre-Lasik Rx.

Time will tell if you mourn the loss of that myopia as you age. I for one, considering how thin lenses can be today, would never surrender that "close focus!"

But that's me. And don't you rant-on back here, ya hear me Petey!

Thanks for an inspired discussion.

Barry

PS - If yer interersted, check out the Sept 2005 issue of Sky & Telescope magazine for my article on night-myopia and astronomy

[Uilleann]

Barry, are you an astro guy as well???:cheers:

P.S. Looked on the S&T archive and couldn't find your article... :(

[Barry Santini]

Barry, are you an astro guy as well???:cheers:

P.S. Looked on the S&T archive and couldn't find your article... :(

Yes, I've lectured extensively to astrononmers on vision and astronomy, including being a featured presenter at
Stellafane a few times.
Here are some links: http://pqasb.pqarchiver.com/skyandte...esight+Insight

The article was authored my S&T editor Josh Roth, but based on the paper and presentations I made at Stellafane.
I also contributed to another article in the same issue called "Lasik and the Amateur Astronomer."

http://pqasb.pqarchiver.com/skyandte...ctacular+Skies

I was also Product and Marketing/Sales Manager for Tele Vue Optics for about 22 years.

FWIW

Barry

[Pete Hanlin]

BTW, there appears to be, from my perspective, quite a bit of possible latent "eyewear hate" in your statement about your pre-op, pre-Lasik Rx.
I could not wear disposable soft contacts (at least for any length of time, anyway) due to my tear properties. So, I was always in -4.75 lenses from morning to night (which can get inconvenient). I don't hate eyewear, but I enjoy being able to tell the difference between shampoo and conditioner in the shower, and occasional freedom from eyewear (sunwear is an absolute must anytime I'm outdoors- I can't stand sunshine :^).

Time will tell if you mourn the loss of that myopia as you age. I for one, considering how thin lenses can be today, would never surrender that "close focus!"
Lenses are certainly thinner now than when I entered the field ('89)! If the FDA didn't keep us from using 1.8 index thin ARC glass, I'd probably be happy wearing that product (dispensed one pair of those to a -11.00 Brit who wouldn't wear anything else)! When I had LASIK, I asked the Ophthalmologist to leave me at -0.25 to maintain near vision for at least a few extra years.

And don't you rant-on back here, ya hear me Petey!
There, that wasn't too rambling! ;)

[Uilleann]

Yes, I've lectured extensively to astrononmers on vision and astronomy, including being a featured presenter at
Stellafane a few times.
Here are some links: http://pqasb.pqarchiver.com/skyandte...esight+Insight

The article was authored my S&T editor Josh Roth, but based on the paper and presentations I made at Stellafane.
I also contributed to another article in the same issue called "Lasik and the Amateur Astronomer."

http://pqasb.pqarchiver.com/skyandte...ctacular+Skies

I was also Product and Marketing/Sales Manager for Tele Vue Optics for about 22 years.

FWIW

Barry

TeleVue - DROOOOOOOOL :D

Sweet gigs man! I was at the local planetarium here for years as well, and spent some time at one of the local binoc/telescope stores also as their regional ocular 'go-to guy'. Great stuff!

[sharpstick777]

...That brings me to fad product that just really causes me to seethe- namely, yellow tinted "night driving" lenses. Basically, placing ANY tint in front of the eye will reduce contrast sensitivity (because less light is making it to the retina). Anyone who could theoretically benefit from a yellow tint (e.g., someone with advancing cataracts) probably shouldn't be driving at night anyway. I would discourage practitioners from prescribing any kind of tinted lens for night driving (at least in the Dallas / Ft. Worth area :^).

Dang- another rambling post! :o

Pete, keep rambling...

What would you do for these patients who have brightness/ light sensitivity only at night, epecially with the newer Xenon headlights? I have 3 to 4 patients year (mostly hyperopes) who say they are blinded or bothered by oncoming headlights. One woman who wanted tint for night driving told me she was closing her eyes with on coming cars. I had to balance the effect of someone driving with her eye closed vs. driving with tint. I did put a crux solid 8% tint w/ A/R assuming that although the Crux is blocking some light, an uncoated lens is blocking more. I asked her to sit in her car pulled over by the side of road to test tints at night and she felt the crux was the best. Over all she said it took the "bite" out of the light. She wanted to go darker but I recommended against it.

On another patient with the similar issue I ended up using a Polarized brown A with good results (with his Drs. permission) after everything else failed. He is an outside salesperson so not driving at night was not an option.

Part of me wonders though if the issue is irregular astigmatism that only manifests its self as the pupil gets larger (we don't have topography darn it). The other thing I wonder is if SV FF lenses would increase their help(these were before SV FF was available). Neither of these patients were diagnosed photophobic (although I wonder), and neither exibited problems in daylight.

What would you do?

Sharpstick

[Pete Hanlin]

Sharpstick,
You are correct regarding pupil size. It definitely plays a role in decreasing vision at night (because the effect of corneal aberrations is increased with the larger lens stop).

Honestly, I just do not believe FF products are going to make much difference- since the aberrations are not symmetrical (a corneal topography will show the irregularity even with astigmatism). I'm sure there will be those who disagree.

The best advice I've seen is to look to the white line on the side of the road when faced with oncoming headlights. If that just doesn't work for the patient and I HAD to give them a tint, I would make sure it was gradient and just at the very top. That way, the head could be tilted down in the presence of bright light- but brought back to clear viewing when the light is past.

Best regards,
Pete

[i care guy]

Thanks Barry... We will be ordering them soon.

What lab are you using? Have they replaced all your Aspheric lenses or are you offering 3 levels of SV lenses to patients?

Sharpstick

Good point.

********************

Dear Sharpstick, I posted this a few days ago and wondering if you could offer any help?:)

Dear all,

My brother is looking to relocate to either Seattle or Spokane and is looking for a job. He's an optician with license at another state.
Do you have any jobs that can offer him or any suggestions?
Is this a good time to quit his old job and move across the country to another state like WA?
What's the rentals for 2 -3 bedrooms apartment ?
Does he need to write an exam for WA license?
Your help is much appreciated.

Regards, M:)

[midohioeye]

When pts complain of night vision problems, one of the things we discuss (along with ar etc) is the brightness of the dash lights. From what I have been told it is primarily personal prefernce, but with the dash lights at there brightest, the pupils are smaller and less glare enters the eye. If the lights are dimmed low then the pupils are less constricted letting more light in. I don't think it will solve all there problems, its more of a personal comfort level. I prefer my dash lights low, it seems to remove the glow or glare from the dash and helps with me with on coming cars lights.

[Pete Hanlin]

I prefer my dash lights low, it seems to remove the glow or glare from the dash and helps with me with on coming cars lights.
Apparently you are not alone... I purchased a Saab a couple months ago (yeah, 2 weeks before they went bankrupt :^), and there is a button called "Night Panel" that turns off all the dashboard lights (except the lower portion of the speedometer). I actually prefer to have the panel lit, but I suppose its to help the driver see better.

One woman who wanted tint for night driving told me she was closing her eyes with on coming cars.
Obviously, if the patient is closing her eyes, a solution needs to be found. In a perfect world, we'd have electrochromatic eyewear that could instantly change in localized areas to block glare (many rear view mirrors are electrochromatic- autodimming- but they're too slow for our dream product).

Wearing tinted lenses at night is particularly troublesome for older patients. The retina of a 60 year old receives about 1/3 the light a 20 year old retina receives. So, between scattering and loss of opacity, a person typically loses access to almost 70% of the ambient light! Additionally, the retina becomes somewhat less responsive with age. Then you have to figure a driver is losing 5-8% due to windshield reflections (and, if the driver doesn't have AR coating, 6% or so to spectacle reflection). Keep in mind the windshield and eyewear reduce the light that enters the eye- so the above figures aren't completely additive. Let's estimate a driver with non-AR lenses loses a total of 11% of light to the windshield and eyewear. That's 89%- and the senior eye loses 60% of that (to be conservative). So, the senior driver is working with about 35% of the image's available light!

All that considered, I'm just a bit hesitant to take away another 10% of the 35% in the form of a tint! However, I didn't mean to criticize anyone who is providing tint as a last resort. My gripe is with some manufacturers (not the majors- but some sunglass makers) who are promoting "night driving glasses" with yellow tints with the promises of increased contrast sensitivity.

[Barry Santini]

. My gripe is with some manufacturers (not the majors- but some sunglass makers) who are promoting "night driving glasses" with yellow tints with the promises of increased contrast sensitivity.

Maybe not increased contrast, but rather, they enjoy reduced *dazzle*, since the yellow does not materially reduce the minimum level of black-background, but does reduce the amplitude of the brightness from the oncoming headlights.

Kinda-like Nike's claim for the mauvey, Golf sun tint...but for night.

Barry

[drk]

Barry, that's not scientifically accurate.

Any yellow tint that absorbs 10%...absorbs 10%. It is not a selective absorber in any way (other than color).

Meaning: yes, the background will indeed be 10% darker and the light source will be 10% darker as well, and contrast will remain the same.

The main issue with headlights at night is not really optical, it's retinal. The dark-adaptated retinal sensitivity increase makes those headlights really, really bright, and that hurts!

Sure, you can dim the headlights with a tint, but it makes the background all the darker.

There is no solution, really...If you do up the dashboard luminance, then that's the same as wearing a tint...it reduces the dark adaptation somewhat. Hey, you could drive around with your map lights on, but that's even worse.

I think the gradient tint is creative, but depressing your head for headlights is sort of like closing your eyes.

[Barry Santini]

My thoughts about yellow and its effect at night are premsied upon the "darker/blacker" areas around the lights being dark enough that the tint *does* effectively act as a selective filter, reducing the dazzle *more* than it further darkens the background.

or so my training in contrast screens for television sets had taught me.

Barry