 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
Medical Forum / General / Vision / August 2005Anti Reflective Coating Necessary and Worth the Trouble/Cost?
I read a lot of the old posting on this topic, but I'm wondering if the latest technology might change the answers some. I'm about to get new lenses and I was going to skip the AR coating because it deteriorated so badly on my current pair. The opthamologist told me I should definitely get it since it would give me better vision. He also told me to not to ever use the cloth that was given to me for cleaning the lenses and to use only softsoap and water. Wow, that was a shock. I suppose I could have contributed to the deterioration of the coating but then the optician had not given me correct information. The lenses are 2 years old, but I'm not sure just when the lenses started to go bad. So is it really true that the coating makes that much difference in the vision? Is it worth the added maintenance? How do I know if the place I'm using uses a good enough place to do the coating? I also need to update my sunglasses. Can I skip the coating on sunglasses? thanks all. Myrna I've had AR on every set of lenses for the last what, 10 years? I have always used dishsoap and an old cotton diaper to clean my spectacles, going back to the days when I was able to wear glass lenses. I'll put up with a smudge rather than use my shirttail. I've never had a problem with the AR coating on the lenses, tho minor scratches do accumulate over time no matter how careful I am in cleaning my lenses. I do think you'll find a difference in your optics without AR. I used to have a lot of trouble with "ghosts" - reflections on the back surface of the lens of things happening behind me, including the occasional look at my own eyeball and that was always weird. with the AR I don't have that pleasure and I can't say that I miss it. The AR also seems to cut nighttime glare and I view that as a good thing when I'm driving. +++++++++++++ Reply to the list as I do not publish an email address to USENET. This practice has cut my spam by more than 95%. Of course, I did have to abandon a perfectly good email account... > because it deteriorated so badly on my current pair. The opthamologist > told me I should definitely get it since it would give me better > vision. I wonder if this is accurate. An ophthalmologist would know that antireflective coating doesn't actually increase measured acuity. AR reduces reflections, no more. The "better vision" consists of reduced internal reflections and about 3% better transmissivity. It looks pretty, until it attracts fingerprints and scratches. -MT HI, Mike, He probably said the AR coating will reduce reflections and I misquoted this as better vision. Thanks for pointing that out. Meanwhile, is the reduced reflection worth the trouble of having a lense that attract dust and can scratch more easily? > He probably said the AR coating will reduce reflections and I misquoted > this as better vision. Thanks for pointing that out. Meanwhile, is the > reduced reflection worth the trouble of having a lense that attract > dust and can scratch more easily? It's a personal decision, not one to be made arbitrarily by the doctor, nor something that should be _required_ on a written Rx. Just my opinion. -MT I don't think that reducing reflections is at odds with "better vision". Since you get significantly more light through to the eye, night vision can definitely improve with AR, and the higher the index of the lens, the more dramatic this effect is. Obviously, you would pick up faint objects on a dark road sooner with AR than without. I'd concur with the o.m.d. that that constitutes "better vision". Newer coatings are much better in the dust and scratch departments. I personally think they are worth it for many people, and use them myself. Re cleaning, I still say NO cloth. Rinse, clean with a mild cleanser or soap (I prefer windex) using CLEAN fingers, rinse thoroughly again with warm water, then gently dry with a paper towel, no more rubbing than is necessary. Above all, never use those cute little microfiber cloths more than a few times. They load up on the dust and micro-sand particles, which are the real culprits... w.stacy, o.d. >HI, Mike, >He probably said the AR coating will reduce reflections and I misquoted [quoted text clipped - 3 lines] > > >Re cleaning, I still say NO cloth. Rinse, clean with a mild cleanser or >soap (I prefer windex) using CLEAN fingers, rinse thoroughly again with [quoted text clipped - 4 lines] > >w.stacy, o.d. Bill, The AR coating manufactuers strongly recommend against Windex, primarily due to the ammonia, or household cleansers in general. I believe that some paper towel brands use synthetic fibers that may scratch the lens. Pure paper products like Kimwipes, 100% cotton cloths, and high quality microfiber cloths are preferred as long as the lens is cleaned with soap and water first. Regards, Robert Martellaro ~~~~~~~~~~~~~~~~~~ Optician/Owner Roberts Optical robopt@execpc.com ~~~~~~~~~~~~~~~~~~ "An expert is a person who has made all the mistakes that can be made in a very narrow field." - Niels Bohr >The AR coating manufactuers strongly recommend against Windex, primarily due to >the ammonia, or household cleansers in general. I know they used to, and don't know if they still do, but these days I don't think it's as big a deal. I use windex all the time and haven't noticed any problems. I used to mix up and alcohol/water/lux liquid concoction for AR lenses, but guess I'm getting lazy. >I believe that some paper towel >brands use synthetic fibers that may scratch the lens. If so, I'd avoid them. Decent quality paper towlels or facial tissues without vaseline work pretty well, as does good old TP (some brands hold together better than others). > Pure paper products like >Kimwipes, 100% cotton cloths, and high quality microfiber cloths are preferred >as long as the lens is cleaned with soap and water first. > > The problem with cotton and those synthetic microfibers is that they don't dry the lens very well like paper does, so the patient ends up "polishing" the lens with them, read that as "grinding" them if there's a single particle of micro-sand on them. w.stacy, o.d. >The problem with cotton and those synthetic microfibers is that they >don't dry the lens very well like paper does, so the patient ends up >"polishing" the lens with them, read that as "grinding" them if there's >a single particle of micro-sand on them. > >w.stacy, o.d. I know what you mean about polishing the lens. I just want to scream "stop it"! I always laugh when a client puts their glasses face down on my dispensing table. I warn them not to do that in front of me or they will get one of my "spiels" on proper eyeglass care. You will change your mind about microfiber cloths when you get your hands on the one made by Luminex, distributed by Universal Photonics. It's thin enough to get under the pads and around the lens periphery, and sufficiently absorbent to dry two sets of lenses. 220,000 microfibers per square inch. Costs about four times more than other brands but it's the only cloth I'll use on my glasses, medical instruments, and binoculars, and have been using it since the mid '80's. Regards, Robert Martellaro ~~~~~~~~~~~~~~~~~~ Optician/Owner Roberts Optical robopt@execpc.com ~~~~~~~~~~~~~~~~~~ "An expert is a person who has made all the mistakes that can be made in a very narrow field." - Niels Bohr >HI, Mike, >He probably said the AR coating will reduce reflections and I misquoted >this as better vision. Thanks for pointing that out. Meanwhile, is the >reduced reflection worth the trouble of having a lense that attract >dust and can scratch more easily? I've only had AR coating once on my glasses.. never again. I noticed no difference in vision at all. I was told that I'd definitely need the coating for reading computer but I couldn't see the difference. The only thing was that they were hell to keep clean. So next time I refused. I think it's a case of the manufacturer's fabricating a need and then coming up with the solution. A bit like those ads for disinfectant when first they tell you that your baby will get sick from crawling around the floor...pah! Tom On 7/27/05 11:15 AM, in article vbQFe.5829$6f.5549@newsread3.news.atl.earthlink.net, "Mike Tyner" <mtyner@mindspring.com> wrote: >> because it deteriorated so badly on my current pair. The opthamologist >> told me I should definitely get it since it would give me better [quoted text clipped - 9 lines] > > It looks pretty, until it attracts fingerprints and scratches. I am just at the point of getting new glasses for distance and computer monitor viewing. I have significant experience with antireflection (AR) and other thin-film optical coatings although no experience with ophthalmological applications other than my personal ones. I have trouble deciding whether to get the AR coatings. I have decided to use glass and get AR coatings only if I can get hard durable coatings. In binoculars and other optical equipment, there can be many more air to glass surfaces than the two for ordinary spectacles. For zoom lenses, the reflections can lead to serious degradation of optical performance if AR is not used. I am somewhat ignorant of the kinds of coatings used for plastic lenses, but I suspected that they are not very durable. The key is that they must be deposited on a cold surface because plastic just cannot take heat. Glass can be heated during deposition. This can lead to extremely tough coatings. Some military specifications require using Scotch tape to try pulling the coating off and rubbing with an eraser. The simplest tough coating is a single quarter-wave (green) layer of magnesium fluoride deposited on glass at a high temperature, 350°C or higher IIRC. If done well, that coating just does not come off. It has to be ground or etched off. That coating reduces the reflectivity of a typical interface from 4% to 1%. Higher index glass ordinarily gives higher reflectivity, but performance of this simple coating improves until an index of 1.9 is reached. That will not happen with cost effective lenses. More complicated, multilayer, coatings can provide even better performance, but I do not think that they are used for spectacles. Mike Tyner knows more about such things than I do. Bill I always get AR-coated plastic lenses. I've had good luck, but every so often you come across a bad AR-coating run. Even from a reputable coating vendor, there is a finite chance of an AR coating flaking or rubbing off prematurely. I clean my AR coated lenses with hot tap water, soap, and fingers. Pat dry with paper towel. Never ever rub dry. My lenses are also immersion-coated to make them oleo/hydophobic. This helps me clean and dry the AR surface. Pretty sad, but my glasses (one year old, Seiko lenses) already have one big patch of the AR coating missing. Even sadder is the fact that if I'd discovered the AR coating gone just a month earlier, I could have gotten them replaced under warranty... I was told by alocal optician that there is no warranty on the AR coating since they can't know how the consumer has cared for the lense. What do you make of this? > I was told by alocal optician that there is no warranty on the AR > coating since they can't know how the consumer has cared for the lense. > What do you make of this? It's a pretty cheap joint that doesn't have any anti-scratch warranty. Makes me think that they only have garbage coatings. Depending on which lab and which coatings I get, my minimum is one free redo, additional redos at half price. My best (and most expensive) is unlimited no charge redos for the life of the Rx, or 2 years whichever comes first. >I was told by alocal optician that there is no warranty on the AR > coating since they can't know how the consumer has cared for the lense. > What do you make of this? If you get a Varilux product, you can get Crizal or Crizal Alize, which are two of the most durable AR coatings available. Not sure if they have an unconditional warranty, but if it starts peeling, etc you should be able to bet a replacement within a reasonable time. If it is scratched, then you are probably on your own. |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.