Jump to content


Photo

Eyeglasses - Crizal coatings vs. glass lenses.

  • Please log in to reply
36 replies to this topic

#1 Zeb

Zeb

    Lift Off

  • *****
  • Posts: 9
  • Joined: 20 Jul 2012

Posted 25 April 2013 - 04:32 PM

I need to wear glasses while observing. Before purchasing my new glasses I researched astronomy friendly lens/coating options. The general consensus I got from the web was that glass lenses were preferred for their higher clarity and Crizal Avance coatings were recommended for their A/R and anti-smudge properties. I have unusually long eyelashes so I was particularly attracted to the anti-smudge factor because my eyelashes frequently deposit oil on the lenses.

When I picked up my new glasses today the optician told me they did not have the Crizal Avance coatings because it cannot be applied to glass lenses. I vented my displeasure and let them know that they should have given me the option before substituting generic coatings on the glass lenses. They agreed to let me try the glasses for 30 days and if I am dissatisfied I can exchange the glass lenses with generic A/R coating for plastic lenses with the Crizal Avance coatings.

Do any of you use the Crizal Avance coatings and if so do they live up to the hype or is it just marketing? If you had to choose between glass lenses and top notch coatings what would your choice be? The extra weight of glass lenses isn't a factor. I've been wearing them for 8 hours without a problem.

Thanks,

Zeb

#2 okieav8r

okieav8r

    I'd rather be flying!

  • *****
  • Administrators
  • Posts: 4681
  • Joined: 01 Mar 2009
  • Loc: Oklahoma!

Posted 25 April 2013 - 04:55 PM

Here's my experience with them, for what its worth. I use the Crizal plastic lenses and I love them. I realize that glass is a better lens material, but I sure don't notice any issues. Stars are pinpoint sharp when I'm wearing them, and I'm not aware of any optical aberrations while wearing them. Plastic lenses are also lighter. My glasses are in wire frames, so they are extremely light and comfortable. As far as being smudge resistant and all, I don't notice any difference between the Crizal lenses and anything else--mine still get smudgy and dirty like any others, so I think there might be a bit of hype in that claim. I'm on my second set, and I'll keep getting them with the Crizal lenses until something better comes along.

#3 Geo.

Geo.

    Gemini

  • *****
  • Posts: 3035
  • Joined: 01 Oct 2008
  • Loc: Upstate NY

Posted 25 April 2013 - 05:31 PM

I have 6 diopter in my GOOD eye, so plastic is really the only option for me. This time I went to Walmart, after the $300 frames the optician sold me fell apart for the second time. Glass is their least expensive option and as you note the coatings are limited. As you go up the option list there are specialized Nikon and Leitz optical plastics available with higher refractive indexs. These permit lighter, thinner lenses and this means less distortion when looking through other than the center of the lens. High index plastic lenses can reflect up to 50 percent more light than regular plastic lenses, so anti-reflective coatings are a must. Most premium anti-reflective coatings include a "hydrophobic" surface layer that prevents water spots from forming and makes the lenses easier to clean. Some AR coatings also include an "oleophobic" surface layer that repels skin oils and makes it easier to remove smudges from the lenses. Aculon, Crizal and other produce these coatings. Photochromic lenses like those of Transitions Optical are also available in the form of specialized coatings.

In the end I spent under $500 for distance and reading glases with high performance lenses in Tri-Flex and Wrangler frames. Or less than my last pair at the optician. The service was better and the guarantee no worse. I still have to flip them up at times to get that full FOV, but for detail they are fine.

#4 Starman1

Starman1

    Vendor (EyepiecesEtc.com)

  • *****
  • Vendors
  • Posts: 23417
  • Joined: 23 Jun 2003
  • Loc: Los Angeles

Posted 25 April 2013 - 05:40 PM

I use polycarbonate lenses with anti-reflection and scratch-resistant and anti-UVA/UVB coatings that are rimless. Very, very, light, I forget I have them on.

But let's talk about the anti-reflection coatings available for glasses versus the AR coatings on telescope eyepieces:
Coatings for glasses are barely up to the level of simple MgFl2 eyepiece coatings, and maybe not even that good, even Crizal coatings, whether Sapphire, Avancé or Alizé (I've had all). People who buy glasses usually don't care about whether transmission is 95%, 98.5%, or 99.5%, and they certainly wouldn't pay for the anti-reflection coatings we typically get on, say, TeleVue or Pentax eyepieces.

I wish that such coatings WERE available for glasses.

I've also tried glass lenses and I've actually gotten better plastic lenses from Nikon and Zeiss than I've been able to get in glass. My distance glasses are Nikons, plastic, and to this day, even though my prescription has changed a bit, they are still sharper than anything else I've used.

By the way, in Crizal, their best coating is called Sapphire.

#5 Tom and Beth

Tom and Beth

    Soyuz

  • -----
  • Posts: 3780
  • Joined: 08 Jan 2007
  • Loc: Tucson, AZ

Posted 25 April 2013 - 05:51 PM

I'm going to answer your question from another perspective.

Glass shatters when it breaks. Oh sure, being next to a Telescope you're likely not going to have to worry about it, but many of us also do woodwork and light drilling, and you're likely to wear your glasses for that as well.

Call me OCD when it comes to eye safety. I only have one left.

#6 kenrenard

kenrenard

    Surveyor 1

  • -----
  • Posts: 1562
  • Joined: 13 Dec 2012
  • Loc: Dunmore, PA

Posted 25 April 2013 - 06:21 PM

I have the Crizal plastic. Like an idiot I used them several times on scopes with the eyecup down. I ended up with a nice perfect circle scratch on my right lense. While at the eye doctor with my wife I ask is there any way to get the scratch out. She says when did you buy them? Last summer. Crizal will replace them free for two years if they scratch. I am stunned and they fit my new lenses and off I go.

I can say they scratch and smudge, but I can't believe they just replaced them. It was surely my poor judgement. I now remove my glasses or make sure the eyecup is up.

Not really a comparison for you. But they are a good company and seem to stand behind the product.

Ken

#7 Mike Clemens

Mike Clemens

    Frozen to Eyepiece

  • *****
  • Posts: 7581
  • Joined: 26 Nov 2005
  • Loc: Alaska, USA

Posted 25 April 2013 - 08:07 PM

> I'm not aware of any optical aberrations
> while wearing them.

crizal plastic here... I notice only 1 thing... if something has a lot of pure red and pure blue areas in it, moving my head left to right makes the red and blue areas shift relative to each other (dramatically)

Not a crizal effect of course, just the lenses. Most obvious with heater controls in cars which have the big red HOT loop and the big blue COLD loop around a dial, try moving your head back and forth and watch them. I can actually pass one color behind the other.

#8 orlyandico

orlyandico

    Fly Me to the Moon

  • *****
  • Posts: 5719
  • Joined: 10 Aug 2009
  • Loc: Singapore

Posted 25 April 2013 - 08:24 PM

I didn't even know that glass lenses are still available.

Like George, I need really high correction, and apparently these days high-index materials are all plastic. They scratch much more easily than glass, but I'm good for about 2 years.

I still prefer the FOV without glasses, and there's a bit of contrast reduction with glasses on particularly if there are stray light sources. But oculars like Vixen LVs / NLVs help a great deal with the eye relief issue.

#9 JeffreyHorne

JeffreyHorne

    Lift Off

  • -----
  • Posts: 13
  • Joined: 22 Apr 2013

Posted 26 April 2013 - 12:21 AM

I have terrible eyes, and my new glasses have Crizal Sapphire coatings.

Looking at street lights, the "flare" coming from them is at least 2/3rds smaller than my old glasses with standard anti-reflective coatings.

The flare of lights through my new glasses is almost comparable to wearing contacts. It's good. The main difference between glasses and contacts for me is that my eyes are so bad that they don't make contact lenses in small incremental strengths once you get my level of "horrible sightedness". Glasses are so tailored to your eyes, and you're not limited to "-6.5" or "-7" increments.

It's important to know that most of my previous observing was done while wearing contacts, and I'm almost a "glasses-only guy" now.

I'm very happy with my Crizal Sapphire coatings.

My lenses are some of the newest lenses available. Essilor 1.74. Super thin for my prescription. Supposed to be the thinnest and least curved lenses available. I'm really, really happy with them.

They also have the oliophobic and hydrophobic coatings on them (part of the Crizal Sapphire coatings.) Oil/smudges wipe right off. They're also anti-static. Really nice.

I'm not sure how all of this translates to night sky seeing, but I've spent the past few weekends with my new C8 SE, and I've never been happier. (It's a new scope for me) :)

#10 Chucky

Chucky

    Messenger

  • *****
  • Posts: 421
  • Joined: 16 Apr 2010
  • Loc: Dublin, Ohio

Posted 26 April 2013 - 05:33 AM

<< Crizal will replace them free for two years if they scratch. >>

I got a replacement set for mine....but of course now my lens have scratches...and I'm out of warranty. Oh well.

#11 Kfrank

Kfrank

    Surveyor 1

  • -----
  • Posts: 1833
  • Joined: 20 Dec 2008
  • Loc: Northern Colorado

Posted 26 April 2013 - 09:59 AM

AFAIK, Crizal is the coating system. Perhaps they only put it on particular lenses though, I don't know.

Glass is, IMO, the best medium for eyeglass lenses - except for the weight. If your lenses get thick, glass can be considerably heavier than polycarbonate.

As to the Crizal coatings, I've had 2 pairs. The first, a number of years ago and my present pair, which my optician assured me were "much improved". Both were/are TERRIBLE.

They smudge worse than the basic uncoated polycarbonate lenses and are much harder to clean to a smudge-free finish. And, they cost a huge premium over the basic lenses.

I'll never waste my money on Crizal, or any other AR coatings again.

#12 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 44750
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 26 April 2013 - 10:35 AM

I'm going to answer your question from another perspective.

Glass shatters when it breaks. Oh sure, being next to a Telescope you're likely not going to have to worry about it, but many of us also do woodwork and light drilling, and you're likely to wear your glasses for that as well.

Call me OCD when it comes to eye safety. I only have one left.


I used to wear glass lenses. Then one day as I was riding my bicycle home from work a Yellow Jacket flew in my helmet. In the rush to remove the helmet, my glasses hit the pavement and one lens was shattered.

My next pair was plastic.. they've been great. I have the transition etc... need new ones though...

Jon

#13 mikey cee

mikey cee

    Cosmos

  • *****
  • Posts: 8193
  • Joined: 18 Jan 2007
  • Loc: bellevue ne.

Posted 26 April 2013 - 12:17 PM

My glasses are plastic. I had three choices glass, poly or scratch resistant transition UV coated and love them to death. I'd have gone thru two sets of plastic readers by now all dinged and scuffed up. These lenses just don't scratch up which is very evident to me. They actually cost less than the poly ones because of the high demand. ;) Mike

#14 Jim Romanski

Jim Romanski

    Vanguard

  • *****
  • Posts: 2257
  • Joined: 02 Jan 2005
  • Loc: Guilford, Connecticut

Posted 26 April 2013 - 04:11 PM

My everyday progressive lenses are polycarbonate. They work well and I'm quite happy.

But I have a pair of glasses that I use strictly for astronomy and they're made of glass. Glass is better optically and will not scratch as easily as plastic even if the plastic is coated. My astro glasses sit very close to my eyes so I can see the entire field of my Ethos with only 15mm of eye relief. My eyelashes touch on occasion but I can clean them off if needed. They were prescribed with about 1/2 diopter additional near sighted correction. This helps with "naked eye" observing.

#15 Starman1

Starman1

    Vendor (EyepiecesEtc.com)

  • *****
  • Vendors
  • Posts: 23417
  • Joined: 23 Jun 2003
  • Loc: Los Angeles

Posted 26 April 2013 - 04:31 PM

Glass is better optically

This has not been my experience. I have had several pairs of both and I have had turkeys in both types.
Generally, though, my plastic lenses have had superior coatings for anti-reflectivity. I suspect it is simply because of the much higher popularity of AR coatings on plastic lenses.
I find it a little amusing that my best glasses have used lenses from Nikon and Zeiss. I guess if you do optics well, you do optics well.

#16 Zeb

Zeb

    Lift Off

  • *****
  • Posts: 9
  • Joined: 20 Jul 2012

Posted 26 April 2013 - 04:32 PM

Thanks for the responses everyone. I'm going to wait for a clear night and use these glasses before making a decision. These are the first "glass" glasses I've had since I was a child. I've been wearing them for a day and a half now and the added weight isn't an issue.

I am an avid woodworker but I have a pair of prescription safety glasses I wear in the shop so for normal daily tasks I don't feel glass is less safe than plastic. One thing I've noticed is that these seem to be easier to clean than my old glasses.

My eyes are not terrible but I hate the glasses on, glasses off dance required to find and then observe objects. All of my eypieces have 18mm or more of eye relief to accommodate just leaving the glasses on and seeing the entire FOV.

#17 GeneT

GeneT

    Ely Kid

  • *****
  • Posts: 12841
  • Joined: 07 Nov 2008
  • Loc: South Texas

Posted 26 April 2013 - 06:36 PM

Here's my experience with them, for what its worth. I use the Crizal plastic lenses and I love them. I realize that glass is a better lens material, but I sure don't notice any issues. Stars are pinpoint sharp when I'm wearing them, and I'm not aware of any optical aberrations while wearing them. Plastic lenses are also lighter. My glasses are in wire frames, so they are extremely light and comfortable. As far as being smudge resistant and all, I don't notice any difference between the Crizal lenses and anything else--mine still get smudgy and dirty like any others, so I think there might be a bit of hype in that claim. I'm on my second set, and I'll keep getting them with the Crizal lenses until something better comes along.


Ditto...Ditto...Ditto.

http://www.cloudynig...rd=Eyepieces...

#18 piaras

piaras

    Viking 1

  • -----
  • Posts: 827
  • Joined: 26 Jan 2009
  • Loc: Niagara Region

Posted 26 April 2013 - 07:06 PM

 To clean my polycarbonate progressive glasses I have been using this stuff for the last 10 yrs. Cleans all the grease off and when using lint free cloths no debris is left behind. Never had issues with coating failures and etching etc. My eyes wear out before the specs do. :bawling:

BTW my telescope optics are dirtier than my glasses all the time.

Ethyl Alcohol, Lab Grade, 95% Denatured w/IPA and Methanol, FSE

#19 Midnight Dan

Midnight Dan

    Voyager 1

  • *****
  • Posts: 11519
  • Joined: 23 Jan 2008
  • Loc: Hilton, NY, Yellow Zone (Bortle 4.5)

Posted 26 April 2013 - 07:57 PM

My regular glasses are plastic, but my astronomy glasses are glass. I find the images to be sharper than my plastic lenses. Plus you can clean them aggressively and not worry about scratches further degrading the view.

And you can definitely get anti-reflective coatings applied to the glass ... I did. Might not be the "Crizal" brand name, but I don't really think that matters. Don't ask for Crizal, just ask for an anti-reflective coating.

-Dan

#20 piaras

piaras

    Viking 1

  • -----
  • Posts: 827
  • Joined: 26 Jan 2009
  • Loc: Niagara Region

Posted 26 April 2013 - 08:10 PM

I have never broken a glass lens in the 40 yrs of wearing the things. Chipped one once, but all the times they hit the ground hard or soft never broken. Even when I got hit with a hard ball right between the eyes. They were always hardened to reduce the chance of breakage.

I also have a second pair that is 1/4 diopter different, that I use when looking up. The stars are sharper. This is per the article from S&T a few years back. They are a simple plastic coated lens but only for distance. If I change them, the next time I will make them bifocal so I can use them to read charts etc.

#21 Chucke

Chucke

    Vostok 1

  • -----
  • Posts: 101
  • Joined: 12 Mar 2010

Posted 26 April 2013 - 09:35 PM

I once tried polycarbonate lenses. I did not like them at all. They had terrible off-axis dispersion. I went back to glass.

Chuck

#22 woodworkt

woodworkt

    Mariner 2

  • *****
  • Posts: 240
  • Joined: 07 Jun 2006
  • Loc: Northern Virginia

Posted 26 April 2013 - 10:49 PM

Being extremely near-sighted with astigmatism, I've tried a lot of different glasses over the years. Something I've always discussed with my opticians is that my prescription tended to cause chromatic aberration with normal polycarbonate lenses, among other problems. Which, unfortunately, made my glasses the weakest link in the optical train with my APO refractor.

There can be a big difference in glass lens glasses, just like plastic. I once had a pair of glasses made with a particular extra low dispersion Zeiss glass (I forget what variety now, but it was years ago) that I guess would be similar to FPL-51 or FPL-53, which I kept just for astronomy. I found out about it in a side conversation with Company Seven in Maryland, when I was there looking at an eyepiece or something, and decided to give it a try. Optically they were great. They were, however, too fragile for normal wear; they weren't hardened the same way normal glass eyeglasses would be... and they were heavier (and more expensive) than normal glass lenses. I accidentally dropped them on a bathroom floor one morning, however, and a lens shattered completely. It was replaced under warranty--I had one that covered accidental breakage--but I eventually needed a new prescription, and the breakage incident made me decide not to go that route again.

I've also tried various low-dispersion plastic variants, with various Nikon and Zeiss coatings, and been a bit more happy with those, because they were fine for normal wear as well. But they've still been worse optically than the Zeiss pair was.

More recently, a conversation with an optometrist I trust (one whose attention to detail discovered a real problem with one of my wife's eyes in time for a retina specialist to do something about it) convinced me to try a pair of glasses made from a wavefront-guided map, akin to how LASIK is prepped, and those have been great... probably my favorite pair ever, even counting the Zeiss glass pair. The company that made them no longer does so, but more recently I've seen Zeiss pick up the same idea (I think they call it i.Scription), and that's probably what I'll go with next time. If anyone has tried i.Scription, I'd be really curious what you thought.

Thanks,
--Ken T.

#23 FeynmanFan

FeynmanFan

    Viking 1

  • *****
  • Posts: 588
  • Joined: 18 Feb 2011
  • Loc: N Colo front range

Posted 26 April 2013 - 11:11 PM

I have a pair of Crizal lenses in my glasses, and I'm fine with them. Two years, and no scratches, but I always wash them with liquid soap in the sink.
As far as glass vs plastic goes, I switched to polycarbonate lenses after a fishing trip about 30 years ago. In the course of trying to free a snagged lure, the thing came loose and zinged into the left lens of my glasses. If I had been a fraction of a second slower closing my eye, well... Some cuts on my eyelid, but no worse. No more glass lenses for this kid.

#24 gnowellsct

gnowellsct

    Fly Me to the Moon

  • *****
  • Posts: 6839
  • Joined: 24 Jun 2009

Posted 28 April 2013 - 02:46 PM

I have plastic glasses for diurnal life and glass glasses for astronomy. Glass glasses serve two functions.

1. Durability. You can look through the eyepiece, brush up against the finder, wipe them with whatever, and the finish lasts and lasts.

2. Better correction. I asked an optician why if my prescription was the same in both eye glasses the glass ones seemed better. His reply: You can't match the refractive properties of glass.

And I thought "Oh yeah, that's right, that's why our scopes are made of glass, not plastic."

that's what I do,

Greg N

p.s. I just keep the glass glasses in the car. They also are handy as a backup if the regular glasses have an issue. They are significantly less comfortable to wear because of the weight. On a hot sweaty day they keep falling down your nose. GN

#25 GeneT

GeneT

    Ely Kid

  • *****
  • Posts: 12841
  • Joined: 07 Nov 2008
  • Loc: South Texas

Posted 28 April 2013 - 04:04 PM

I once tried polycarbonate lenses. I did not like them at all. They had terrible off-axis dispersion. I went back to glass. Chuck


For some of us, glass glasses would be too thick and heavy. I spend a lot extra for the super thin polycarb lenses because the regular plastic lenses (although much lighter than glass for my prescription) are too heavy.






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics