billdianne

billdianne

Active Member
Patron
I have been having a love hate relationship with progressive lenses for a number of year's now. Mainly with the peripheral limitations and correction in the middle of the lens. I have been reading about a new lens by this company
http://www.izonlens.com
that uses wavefront guided technology, similar to what they use in lasik surgery
only instead of shaping the eye they shape the lens.
Just wondering if anybody has had any experience with this good or bad.
Any OD's out there care to comment?

thanks,
Bill
 
progressive lenses

i don't know anything about these new lenses, but i also experienced some frustration with progressives. i first got prescribed bifocals about 17 years ago. i did have a little problem with the loss of clarity in the peripheral vision, but eventually learned to turn my head to focus. the original lenses i got worked pretty well top to bottom in finding intermediate focal points for intermediate distances. in my work i look at monitors all day long.

coupla years later, my vision had changed a little, so i got a new perscription. i had moved to a new city since the initial diagnosis, so i had to use a new eye-doctor and glasses supplier. i got a different brand of progressives, and although the far vision was improved (and the near vision as well), i couldn't seem to find intermediate focal ranges. i relegated the glasses to "driving glasses", and continued to use my old ones for looking at monitors (and the instrument panel, as well.) when i decided to replace them again, i decided that i would go with the original brand of lenses, so i called around shops to find one that could get me that brand (actually the first one i called said they could get them, so i went there.) while there, the eye-doctor (i'm not going to try to spell opt..............) explained the difference in some of the progressives to me, even showing me a "comparison sheet" of about 2 dozen manufacturers. seems my original lense brand had a spread between the far and near focal points of 21mm, whereas the brand i had most recently purchased had a spread of only 10mm. so i ordered the new glasses, and when they arrived, i could see again -- all ranges.

didn't do anything about the peripherals, but as i said before, i've pretty much gotten used to that. btw, the lenses i have found to work for me are American Optical Omnivision Plus lenses. as in anything else, ymmv. obviously, if you are going to have a 21mm spread from top to bottom, you can't use any of the now-fashionable narrow frames.
 
Progressive lenses are NOT equal (as stated before). When I started wearing progressives quite some time ago, I started with Varilux. These were expensive, but Paul Harvey vouched for them. They didn't work well for me at all. After trying several brands, I found that the cheaper brand carried by EyeMasters work best for me. Not sure what brand they are. Everyone is different, so ymmv.
 
Straight bi-focal

A bit off-topic, but I handled Myopia a bit differently. My flight surgeon insists that I be able to see at 16"--much closer than I often read, and as I found out, giving me a bit of blur at car-dash distances. I had new glasses made this way but wasn't happy with them, so I got lenses that gave me clear images at around 20" and all the way out to where my regular lenses took over. Great, except for very close work. Just to see what would happen, I switched one of the old lenses for one of the new (they were for the same frames) and it is the best of both worlds. I have had bifocals for about twenty years and this is the best situation yet. No percieved blur at any distance from 15" or so on out to the horizon. I don't know if my eye-doctor would be happy , but I certainly am. I'll soon find out if the Flight Surgeon is. . .

Bob Kelly
 
CAN'T SEE

I just walked in and turned my computer on after an afternoon of drilling holes in the firewall (brail method). I have to count the number of steps in the step drill as it goes through the metal, crawl out from under the dash, down the ladder, under the engine, check if hole is correct size, and go through this procedure again if not big enough oooof. You can tell I wear progressive lens also. I'm considering lasix but if there is something better I would love to know about it. Have a Happy New Year!
RV-9 G.P.
 
Tri-focals

I solved the problem by using tri-focals...

One each for distance/dash/map reading.... :)

I found the the intermediate lens is not a fancy calculation... they just split the difference between the reading lens strength and the distance lens.

I only bought one pair of variable focus glasses, and always fell over my own feet when I wore them... :D

I quickly relegated them to "meeting glasses" and only used them sitting... :)

...as always YMMV.... gil A
 
Talk to the eye doc.

Well, I am lucky that so far I only need to wear glasses for reading, but I have already discussed the future with my optometrist.

My eye doc is a pilot, and understands what is needed for a pilot.

He plans on making me (when the time comes that they are needed) a pair of glasses just for flying----------bifocal, reading section set for the distance to the panel, and the separation line height to fall at the panel/windshield line while my head is at normal position.

The typical distance for reading glasses is what you hold a book at, 16-18".
From what I have seen, the typical distance to the instrument panel in most planes is 24" or more, out of focus range for the typical glasses.

Talk to your eye doc, and ex-plane what you need, it is easy to build glasses to fit custom needs.

Mike
 
I had to make the switch to bifocals in the last year of my RV-6 build. I went with the progressive lenses and it took some getting used to them, but I was able to adjust. My biggest problem when working on a project is the need to tilt my head up to get things focused, like when working under the panel.

My biggest problem with the progressives is in the flair on taildraggers. I have always tilted my head back to see over the cowl as the flair is entered. With the progressives, this means I'm trying to look far down the runway through the reading part of the lenses and lose all depth perception just as I'm flaring and trying to have a soft meeting with the ground! Wheel landings are ok. I've pretty much settled on wearing a pair of sunglasses which are distance only (non-bifocal) and to read the moving map on the gps, or a chart, etc I just lift up the glasses a little and look out below the glasses. Of course this doesn't help at dusk or later.

I've talked with a couple of full time pilot friends who have experienced the same condition and they use traditional non-progressive bifocals with a slightly smaller (less high) than normal section for reading. I might try that next time I get new glasses.

Dave
 
Blind without

I have progressives and they got me past my medical with flying colors.

Do I wear them when flying...**** No.

I prefer to use contacts and reading glasses, or sunglasses with reading inserts. Contact lenses give a much better depth perspective.

I am at the limit of technology on contact lenses. My corrected vision is currently 20/30 or better, but it has a price, $260 per contact lens.

Backups include a spare pair of glasses and a spare set of contacts in my flight bag.

Can I land without either...no problem. The runway is that long and wide thing with white fuzzballs, the taxiway is lighted with those green fuzzballs,

I'm happy with my contacts. I don't plan on any surgery at this time.

John
 
My eyes are pretty nasty bad, around a -6.5 correction needed (I can't come close to seeing the big E) and am in my late 50's where you can't accomodate well. Even though my pilot optometrist has been recommending trifocals for many many years I am getting by OK with regular lined bifocals. The only time I notice a problem is on the takeoff roll before the tail comes up. I raise my head to see down the runway and am looking through the reading portion of the glasses. I haven't noticed a problem while landing.

Although I haven't tried progressives yet, due to the reported narrow correction range, side to side, if I did I would give them a good long trial. It is really amazing what the brain can do, given a chance.

Back in school, we read about a study where people were given glasses that inverted the image. Given time the brain even adjusts to that and sees things right side up. Pretty horrible adjustment period though.
 
Just Lucky I Guess....

I reached "that peculiar age" a few years ago where I finally admitted I needed a reading correction. I got lots of warnings similar to the postings above that I was going to have a heck of a time flying with my new progressives, so the first time out, I had my old glasses along, just in case I couldn't land. I didn't know what to expect....and what I got was absolutely nothing at all - I have never noticed a difference or problem flying or landing with progressives. This is not in any way trying to contradict those who do - just letting folks know that not everyone has a problem!

Of course, maybe it's just cause I land with my eyes closed anyway... :p

I did have to make some adjustments in my normal job with the progressives - I had to figure out where to look for the displays on my console, and the displays up on the front wall of my Control Center. Controllers got used to seeing me do "the head bob" for awhile.

(I have no idea who makes mine - whatever Eyemasters sells...)

Paul
 
I had Lasik 1 year ago. I am happy with it. I had always needed correction for distant (-2.75), but never reading. At 45, I was begining to need reading glasses. I opted for Lasik to correct distant. As it stands now, I need neither correction. But. . . I will wear reading glasses for fine detail type things (1.0). Either way, all restrictions are gone both for the private, class 3 medical, and my drivers. I need a small "Enhancement" in the left eye. The Doc told me to wait. Currently in the U.S., the lasik procedure can only correct for near or far, but not both. He says the FDA should approve a procedure this year to correct for both near and far. It has been approved in Canada for several years.
YMMV
 
Last edited:
billdianne said:
(snip) wavefront guided technology, similar to what they use in lasik surgery
only instead of shaping the eye they shape the lens.
(snip)
thanks,
Bill
Click to expand...


Hi Bill.

I don't have any experience with this particular company or product, but I do have a fair amount of experience and expertise with "wavefront guided technology" and optics. My BS detector is buzzing loudly here.

The purpose of wavefront guided treatments is to measure, and then hopefully reduce, optical aberrations in the eye. As a rough example, imagine that your eye was more nearsighted in the top half of the pupil as compared to the bottom half. No symmetric lens could correct that perfectly, as it would undercorrect the top half, overcorrect the bottom half, or some combination. A wavefront guided laser can actually vary the treatment point by point across the cornea, removing more tissue where necessary, and leaving other areas less treated. A very,very rough analogy might be made to GAMI injectors.

None of the current lasers measures in real time, but they apply a previously measured "map" to the cornea. A critical part of this process is accurately centering or "registering" the map the the cornea. The tolerances are measured in microns. Spectacle lenses are typically 13-15mm in front of the eye, and don't move with the eye. It's hard to imagine what a wavefront analysis would do for a spectacle lens. Even contacts move around on the cornea a fair amount.

"Wavefront" has been the subject of enough marketing that patients are aware of it and I have seen things like "wavefront assisted lasik" where a wavefront map is measured, and the (non-wavefront) laser is "tweaked" based on the wavefront refraction. This is a lot like the "Digital-Ready" speakers that were all the rage on stereo equipment a few years ago. Those speakers were (and still are) analog devices, whether or not the signal driving them was converted from digital.

It's possible (if you want to give them the benefit of the doubt) that they are making glasses from an electronic automated refractor in finer gradations than the 0.25 diopter steps typically available. I have two wavefront machines that report average "refraction" to a precision of .01 diopters, but they aren't repeatable to anything even near that. When I prescribe spectacles, I use the 0.25 phoropter and lens blanks, even if I have the wavefront measurement in the chart. YMMV.
 
Glasses ... *sigh*

When I started this project, I didn't need ANY glasses except safety. Now, I can't find the plane without glasses!

And these are the Golden Years?? Bah, humbug! :D
 
Presbyopia - another data point

Don't forget that Lasik, (or other laser vision correction procedures), will not treat presbyopia, which is an age related lessening of your eye's ability to vary it's focus towards the "reading" end of the range. I had been nearsighted (about -3.25 diopters or 20/200) since the fifth grade, and had a PRK procedure at age 54. The results for distant vision were very successful, 20/15 and 20/20, but I instantly had to acquire a supply of reading glasses. The exact timing and degree of onset of presbyopia vary, but somewhere in the 40's or 50's, you'll get it. I use a pair of flying only glasses, with the top of the reader segment placed along the apparent top of the panel. In order to read the map in my lap, I have to fudge the correction to a somewhat shorter distance than the panel, and accept a bit of blur there, but not so much as to create a problem. I guess trifocals are next - argh! But before anyone gets too vexed at the idea of all these "special appliction" glasses, consider that some space shuttle commanders take off with up to 5 pairs of glasses to accomodate the various regimes of the flight, and yes, some of them are trifocals. :)
P.S. PRK is not the old "slice around the eyeball" procedure. It's a form of laser correction similar to lasik, and the one currently approved for military aviators.
 
AltonD said:
I had Lasik 1 year ago. I am happy with it. I had always needed correction for distant (-2.75), but never reading. At 45, I was begining to need reading glasses. I opted for Lasik to correct distant. As it stands now, I need neither correction. But. . . I will wear reading glasses for fine detail type things (1.0). Either way, all restrictions are gone both for the private, class 3 medical, and my drivers. I need a small "Enhancement" in the left eye. The Doc told me to wait. Currently in the U.S., the lasik procedure can only correct for near or far, but not both. He says the FDA should approve a procedure this year to correct for both near and far. It has been approved in Canada for several years.
YMMV
Click to expand...
Interesting. I thought the loss of near vision (presb-something) is where the lens hardens and prevents variable focus. Cornea dimensional alteration or lens implant is a fixed correction.

BTW - I had PRK almost 2 years ago. Interesting story on that. The dr. doing the work asked why I chose PRK. IMO, if the US Navy thought it was good enough then it's good for me. He said it'll "hurt like h***". It did! But the results were incredible with somewhere around 20/15 at distance.

But the resulting shift in my focal length and hitting 40 reduced my near vision. I now use Walgreens magnifiers for close up work. Not necessary for flying, yet.
 
Last edited:
Low Pass said:
Interesting. I thought the loss of near vision (presb-something) is where the lens hardens and prevents variable focus. Cornea dimensional alteration or lens implant is a fixed correction.
Click to expand...
Your description of presbyopia is correct, it's a loss of range of focus due to hardening of the lens. Cornial alteration via Lasik or PRK is a fixed correction. I believe that new lens implants are coming on-line that are flexible enough to restore some focal range, so if you had to have one replaced anyway, you could get a little bonus.

As for that "hurt like H***" on the PRK, you got that right! :eek: But at least we won't have to worry about that flap blowing off.
 
marvals of modern science

I too had laser eye surgery. Not the slice and dice type (that just creaps me out, thinking of someone slicing my eye). The "no touch system". Laser off some of the epithelium then correct the vision with the same laser. 20 seconds per eye. With the anelgesic eye drops, the pain was really minimal.
I did the glasses and contact thing for years. The last eye test I had before surgery indicated a need for bifocals, I was only 46 at the time, no way!
I was -2.75/-2.50. This procedure is very popular with firefighters and police
officers as well as (some) airlines here in Canada. Not cheap at $2500 CND per eye. My reading vision was never a problem, it was my distance viz that was the issue. I'm impressed. Transport Canada re-issued my medical 6 months post surgery. The wife had the same procedure (-9.5 diop) with some "staring" at night. No, it's not without some risk.
 
Last edited:
A few rambling thoughts about vision correction...

This is an interesting thread. Thanks to all you guys for sharing your experiences. I am nearsighted (about 20/300) and have been since age 12. Since I spent so much time as a teenager in the optometrist's office, that was my first career choice. But then, someone said I should be an engineer, and now I are one!

I've kept up with the various surgeries through the years but haven't yet made the decision. They are making so many advances in corrective sight surgery, I'm wondering what new surgery is right around the corner. Right now, I am very happy with gas permeable contacts for distant vision (20/20 and 20/15) and reading glasses from WalMart, Walgreen's or wherever.

I even have a pair of bifocal contact lenses that I still wear occasionally but since I found out they are illegal for flying, I don't wear them in the plane. That's another topic, but the bottom line is don't act as PIC while wearing any contact lens for near vision which includes both bifocal contacts and the common practice of "monovision" using one lens for near and one for far. I have noticed that with my bifocal contacts my near vision focal length is in the order of 12-14 inches and is quite narrow, whereas my near vision through both distant contact lenses and reading lenses has a "depth of field" of apx. 12 inches out to about 24 inches. So for my vision while flying, the legal way works better for me.

I have even been seen wearing my reading lenses on the tip of my nose and my sunglasses on the bridge of my nose. That's one joy of getting older...I don't really care if it doesn't look cool! ;) Hey, it works.

I remember a welder a few years ago who had a special pair of bifocal glasses with the reading lens in the top of the lens. That way when he was welding overhead, he could better focus on his weld (through his welding helmet, of course.) As I became presbyopic, I remembered him and came to appreciate his solution. Maybe us old presbyopic builders should have such a pair out in the shop for some of our unusual attitudes while building. I would love to hear if anyone has done this while building an RV...

Larry, I thought your story about the study group wearing and adjusting to lenses with inverted vision was going to lead to a punch line about aerobatic pilots flying inverted but looking at the world right side up!!! Wouldn't that be a hoot?

I haven't tried the progressive lenses yet, as my present glasses which are bifocal are for backup only.

Thanks, again, everyone for your experiences. I was not aware that there were so many differences in the lenses provided by the optometric community. This explains why my wife has had some difficulty getting a good lens fitting with a different optometrist. I suspect he only buys from one or two lens/frame suppliers when in reality there are probably more than two dozen to choose from.

I'm out!
Don
 
Last edited:
Progressives are good

rv7boy said:
But then, someone said I should be an engineer, and now I are one!
Click to expand...

I are an Engineer too...

I did want to "clarify" one thing on my experience with progressive lenses. I was told that the side vision would be bad. In my experience, the side vision was OK. Not great, but I could see peripheral objects with a bit of fuzziness, far better than without glasses.

The side clarity really is not as issue. However, the ability to see intermediate objects was a vast improvement over bifocals. (I don?t have any experience with Tri-Focal). I am very happy with my progressives, and would suggest them to anyone.

I thought about RK surgery many years ago, but avoided thanks to my doctor?s recommendation against. I then thought about Lasik, with my doctor?s approval, but there was a good chance I was not correctible to 20/20, and would still require contacts after the surgery. (-7.5 / -2.5 astigmatism)

Then I found a web site devoted to recovering eye surgery patients. It scared me so much, that I decided against any surgery. http://www.visionsurgeryrehab.org/

I did hear about progress on replacing the cornea with a lens that corrects presbyopia, giving full vision back. Only on cataract patients for now, but who knows what the future brings.

After paying $650 for the progressive glasses, and $260 per contact lens, I?m ready for surgery correction, but I?ll wait just a bit longer, it?s the engineer in me?

John
 
Well the eyes have it...

Hi, my name is Kent and I use bifocals.

The last set I ask that the lower part be ground to place the panel in correct focus. Not ideal for reading maps, but I can get by. :eek:

As for working on the plane, I have three different strength of cheater glasses. I switch off depending on how close to the work my eyes will be.

It is kind of fun to see me laying down under the panel with all three pair and a flash light. :eek:

Kent
 
I wear glasses for 20:infinity nearsightedness so the effects of presbyopia are somewhat mitigated for me still at 47. However, when I climb under the panel of my 6A, forget it. I found, after some searching, some clip-on, full size reading lenses. They are essentially like the full size clip-on sunglasses, but with +1 to some higher number available. I ordered them on the internet, and they were pricey at $25 to $30. I was in a local welding supply store and found the same thing for less than half that price.

As for seeing the panel when flying, there is no problem in daylight, but at night it is a bit tougher. I just slide my glasses down my nose perhaps 1/4" to "depower" them, and everything is back in focus.
 
Try Cataract surgery

I had been using progressives for about 10 years with little problem, but then I noticed many white things having tan/orange hue. Had my eyes checked, and I had cataracts...age 70 +/-. had both eyes done 2 mo's apart. great results.
My progressives are pretty much clear for distant vision, and corrected for inst panel and reading, most of the time I really don't use them.
I hear there are bifocal implants now, but suspect quite expensive.
Just a little food for thought.
Harold..RV9A ....still building..fuse now
 
You must log in or register to reply here.