Does AR really cause multiple images for night driving?

**eyevay** · 11-09-2002, 08:56 PM

I'm hoping someone here may shed some light (pardon the expression) on something I heard the other day.

Patient comes in & while discussing coatings, she said she had read some new information that was researched by an Australian company. Apparently glare & reflection are big issues Down Under as the sun is very bright there. The Aussies are on the forefront of contact lens resesarch also.

The research said that when driving at night, the main visual problem was not so much reflections but the eye receiving multiple images from (1) oncoming headlights, (2) street lights & signs, & (3) light bouncing off the road surface when wet. The researchers had concluded that AR actually exaggerates & increases the multiple images, aggravating night driving. This is contrary to what most of us have been telling folks! Most people I know who have AR say it helps their night driving. Anyone have a handle on this?

eyevay

**Steve Machol** · 11-09-2002, 09:01 PM

Sorry but that sounds like nonsense. A/R Coatings reduce internal reflections like this - not increase them.

Do you know the name of this company or have a link to this research?

**eyevay** · 11-09-2002, 09:43 PM

Well that's what I thought too. Pt. kept saying that the issue was "images" not "reflections" but I don't really understand what this means. If I see the person again I will ask for more info on who did this resesarch.

**Steve Machol** · 11-09-2002, 09:46 PM

Where exactly does he think the 'mulitple' images comes from? The only source (other than alcohol!) would be reflections. ;)

**optigoddess** · 11-10-2002, 01:25 AM

Hi, Joy! (Eyevay) -

I know this is off-topic, but HOW ARE YOU!?! and Where are you? ! ?

Curiously yours-

Karen

**John R** · 11-10-2002, 02:56 AM

Well from personal experience. I can assure you that ARC does NOT make multiple images worse....And as for No 3 we get plenty of that here and if i ain't got my ARC glasses i have to take them off to drive as its soo much worse.
Must be a company with a new product too sell and first they need to discredit the competition.

**David Wilson** · 11-10-2002, 08:53 PM

This is news to me too. I tend to agree with Steve. I'd be curious to know the name of the Aussie company. The only lens company with a research department in Australia is Sola (to my knowledge). The universities certainly have research departments and, as you say eyevay, the University of NSW is a world leader in contact lens research. John may also have a point. recetly heard of one lens company using the polariscope to highlight what they called chromatism in a polycarbonate lens. I like to think that it is ignorance though, John.

Regards
David

**Homer** · 11-13-2002, 07:58 PM

I had been in the optical business for about 3 years when I got my first -.50 OU at age 23. I loved them .... except at night. There were other images, images of the on-comming headlights that moved around as I moved my head. I could make some of them disappear when I looked directly at a light source. The opticians in the office called them ghost images. It think that is a good term.

The researchers are right, it is not reflections that are confusing and frustrating, it is the ghost images. Of course they are cause by the external and internal reflections at the lens surfaces which can be greatly reduced by anti-reflection coatings ..... which reduce the reflections which are experienced as ghost images.

Think the patient mis read the researchers results related to anti-reflection / anti-ghost image coatings. I know that I, and a host of my patients would not be caught dirving with a naked lens.

Better have the patient bring you the article.

**Texas Ranger** · 11-16-2002, 04:45 PM

not mentioned in the source of multiple reflections is the biggest problem, the windshield. so, it's like this, you have a lot of reflection problems, so why add to those others with non-ar lenses? would you have all those reflection problems is you wore NO glasses? so the premise is way wrong...

**edKENdance** · 11-17-2002, 12:09 PM

I think I've seen some newer mini-vans driving around with a/r windshields, I might be mistaken but they kind of have a purple hue when you see them through polarised lenses.

**harry a saake** · 11-17-2002, 01:13 PM

Strangely enough on page 36 of nov 20/20 Joseph Bruneni has wrote an article stating that ar causes reflections. I know i,m confused and certainly would like to invite Mr. Bruneni to the board here , so he could explain to us what he means and what he is basing that on. Anyone know Joseph?

**edKENdance** · 11-17-2002, 01:33 PM

That's just plain wacky. A light source and a surface create reflections. As I explain to customers on a daily basis, the only reason you see that green/red whatever reflection(no it's not a tint) on the lense is because that's the only colour in the spectrum that's not passing through it. When most all light is reflected it's white which is certainly more natural for our eyes to see but when you put a reflective surface between your eyes and the world, the more light that can pass through it, the better.
Bring on Mr. Bruneni!

**Jim G** · 11-18-2002, 07:38 PM

We're trying to get Joe's complete reply but, here's a start:

"Regarding your question about an article in 20/20, I'm handicapped because our November 20/20 issues haven't arrived yet. I'm puzzled by several things. I write for a number of Jobson publications but not normally for 20/20. Second, I can't imagine I would write that AR causes reflections. Let's wait until I see that issue and then I'll get back to you."

Harry, can you verify the magazine just to make sure; I'll see Joe this week at OLA and we can get a definitive answer for ya.

**harry a saake** · 11-18-2002, 07:48 PM

:D Jim, i didnt mean you wrote this, i believe it was Joe, unfortunately when i came home tonight my wife had thrown out the magazine. As i remember it was 20/20 and it was on page 36. It will be a few days before i am home as i am heading up to the AFOS convention in Williamsburg, and it will probably be friday before i get home.

**spexwala** · 11-19-2002, 02:18 AM

This is coming from India,& I am very selective while suggesting ARC to my patients.You see there is plenty of dust in India,& we indians are very comfortable,wiping our glasses with our shirt,without wetting the lens!!!
The moment a patient collects his ARC glasses,he is pretty satisfied,but comes back fuming in a weeks time.Reason:His glasses are making night driving horrible!Why?Take a look at those ARC lenses,& you wo'nt recognise them,since they are so badly scratched up!!!!!!
Look at the car's windshield,& you'll find why night driving is impossible!

**icare** · 11-20-2002, 12:05 AM

spexwala said: Look at the car's windshield,& you'll find why night driving is impossible!

Brilliant deduction, spexwala. We are so attentive to the issues of the medium in the eyeglass frame but too easily forget the medium in the auto window frame.

**jbruneni** · 11-25-2002, 06:55 PM

This is in reply to the comment that an article by me in 20/20 stated that AR causes reflections.

There's several things wrong with this comment. First, the story was in the November EYECARE BUSINESS, not 20/20 (a minor point). Let me quote directly from the story ("Lenses for Computer Users") which was in the section talking about reflected glare from monitors. Here's what I wrote:

"Another component in CVS involves reflected glare from monitors. The best way to eliminate this is to reposition the monitor or overhead lights. When this is not practical, monitors can be fit with an anti-reflective glare screen. Although AR coatings actually increase the amount of reflected glare reaching the eyes, AR provides other benefits and is usually a useful addition to your patients' computer eyewear."

The key statement was the last sentence. Adding AR to an ophthalmic lens increases the light transmission THROUGH the lens so that more of the reflected glare FROM THE SCREEN enters the eye. It was NOT implying or stating that AR causes reflections.

I do make mistakes and/or omissions in these stories so I'm always glad to hear from readers. Thanks for bringing this to my attention. I spent some time on that statement, knowing it might be mis-understood. I probably should have added the words "FROM THE MONITOR" after the words "reflected glare".

**Steve Machol** · 11-25-2002, 07:02 PM

That makes perfect sense Joe. Thanks for clearing this up. It just goes to show you that it's better to go directly to the source than rely on second or third hand accounts. Things often get lost in the translation from one source to another.

**harry a saake** · 11-25-2002, 08:26 PM

:hammer: Joe, yes let me be the first to apologize for misunderstanding what you meant, and then on top of that not having the magazine to go back to it, as everyone had trashed it. I realized it wasn,t 20/20, but then i could not remember what it was. I,ll make it a point to read more carefully in the future.

**SA - Optom - Girl** · 09-08-2010, 08:26 AM

hi there,

im new here and stumbled upon this site while doing research. I find this discussion very interesting and I wholley agree with what Mr. Joe Bruneni says about ARC not being very effective for computer use ( unless placed on back surface of the lenses if you have an overhead flourescent light behind you).

but he did say that AR coatings have other benefits and is a useful addition to patients computer eyewear. I'd like to know from him exactly what these other benefits are and why.

This has always been a contentious point of discussion here in SA as many Optoms advocate an ARC as soon as they hear the px is a computer user. Surely considerations such as lighting, arrangement of work surfaces in the office, with regards to windows etc and orientation of the computer monitor itself need to be discussed before an ARC is hastily slapped on.

I agree with spexwala - pxs dont always look after their specs and therefore it must be a very well considered decision to prescribe ARC.

That said, I am 8 months out of the University of Johannesburg and Im finding it very useful to hear from ppl who are far more experienced.

**eyeguy21** · 09-08-2010, 12:13 PM

Originally Posted by Texas Ranger

not mentioned in the source of multiple reflections is the biggest problem, the windshield. so, it's like this, you have a lot of reflection problems, so why add to those others with non-ar lenses? would you have all those reflection problems is you wore NO glasses? so the premise is way wrong...

Stole my thunder. I can't tell you how many problems resolve themselves when I ask them "when was the last time you cleaned your windshield?". Never heard of a good, uncompromised ARC that caused problems with night driving.

**Uilleann** · 09-09-2010, 04:33 PM

To be technical - if I understand the mechanism behind a/r lenses, they do indeed create a reflection. However, it's effect is offset to the incoming light rays and set up to cancel out the waveform. So it could be said that in order to cancel reflection, these lenses have to first create a small additional reflection (and most importantly have that reflection offset by a quarter wavelength). Would y'all say that's correct-ish at all?

**WFruit** · 09-09-2010, 04:47 PM

Originally Posted by Uilleann

To be technical - if I understand the mechanism behind a/r lenses, they do indeed create a reflection. However, it's effect is offset to the incoming light rays and set up to cancel out the waveform. So it could be said that in order to cancel reflection, these lenses have to first create a small additional reflection (and most importantly have that reflection offset by a quarter wavelength). Would y'all say that's correct-ish at all?

You are correct sir. (It sound's better in Ed McMahon's voice....)

And yes, cleaning your windshield, especially the INSIDE will greatly benefit your driving vision.

**uncut** · 09-12-2010, 09:16 PM

Originally Posted by Uilleann

To be technical - if I understand the mechanism behind a/r lenses, they do indeed create a reflection. However, it's effect is offset to the incoming light rays and set up to cancel out the waveform. So it could be said that in order to cancel reflection, these lenses have to first create a small additional reflection (and most importantly have that reflection offset by a quarter wavelength). Would y'all say that's correct-ish at all?

Correct-ish! and beautifully stated!:cheers:

**finefocus** · 09-12-2010, 10:03 PM

A/R coatings use destructive interference, just as do noise-canceling headphones. Saying that they create reflections, while true, can mislead. When we decenter a lens to the proper pd, we create prism. Why would we do that? So there will effectively be no prism, right? Same thing; creation and negation are two sides of the same coin.