Help me with my new glasses

[eyedoc]

Hi,

I'm getting new glasses.
My RX is 11.00 in both eyes, no astigmatism.

I have selected a largish frame (56-58) and want full view
glass lenses, I have always used this type of set up and gives me
excellent peripheral vision and acuity to 20/20. I will not
accept anything other than this.


Here is where I need help:

The back of my lenses has always been flat, and it bothers me
by getting in the way of my eyelashes.

For example:
-----------------------------------------------------
My present glasses: |)
My desired glasses: ))

The curve in the back would provide free space for my eyelashes.

So now that I have explained in plain english what I want, could
you experts :) throw some technical terms and suggestions for me.

That is, how do I about explaining this to doc or dispenser?
I want to sound knowledable when I approach the doc's office.

Thanks for your advice.:

[chip anderson]

Son, with a precription like yours you really need contact lenses. But if you must have what you say you want, tell the optician (hopefullly the doctor just writes the precription and sends you to the one of your choice) that you want glass and you don't want a myo-disc or a lenticular. It will be horribly thick, (especially in a large frame) and will not have a flat back. And trust me, you don't know what peripherial vision is till you compare contact lenses in your precription to spectacles in your precription.

Chip

[yzf-r1]

eyedoc said:
The back of my lenses has always been flat, and it bothers me
by getting in the way of my eyelashes.

I too have very long eyelashes (many girls say that they are such a waste on a bloke!!!), but i have the benefit of having a minus prescription, so the back surface of my lenses will always be curved. Even so, my glasses still needed adjusting at the nosepads to give adequate clearance for my eyelashes. This is a very easy adjustment especially on metal frames. This may be a line that you wish to pursue. I must warn you that with your prescription, changing back vertex distance, may necessitate an alteration to the prescription. Your dispenser will be able to calculate this.

By the way, a flat back surface on plus lenses is really something you should not hate because it is done to reduce the front surface curve, hence the thickness and weight.

As for Chip's comments about contacts, Go for it!

Hope this helps.

Yahya

[hcjilson]

Before going into this question much further, I'd like to know the reason glass has been requested, as well as a full field blank.Peripheral vision would not be compromised badly with a lenticulated lens provided the wearer has a full range of motion (ie: not a parapalegic) I also see litte compromise in acuity by the move to plastic. There is something we have not been told here and I am just curious.....

harry j

[Jeff Trail]

Well as for the original question the ONLY way to increase the amount of back curve we would have to increase the base curve (front) If you do not want an aphakic lens, the aspheric lenticular has the blended bowl so it has less of a hard edge egg look, and you are stuck on a full field lens than there are a couple of places to get the bigger base curves... Vision Ease goes to a 14, but if you want a company that really has a wide selection of base curves in SV as well as multi-focals than I would tell the optician about a company called Aire-O-Lite, in SV they run upto a 20 base..multi-focal it's I think around a 16 base and if you ever need the crazy adds this compny stocks upto a 40 or 50 add :-) The only problem you may have is that that 20 base SV is a 65 mm blank so you may have to drop to a slightly smaller frame selection if you have a narrow pupilary distance.
I would have thought that by now you have been told about contacts till people were blue in the face so I'll skip that answer :-)

Jeff

[eyedoc]

Thanks to all for your help and suggestions.

Why glass?
- It is naturally the hardest material, most scratch resistant
- I belive it provides me with better vision
- Heavy? Not an issue


What about contacts?
Actually, I do have contacts, which I can only wear ocassionally.

Jeff, thanks for the lens suggestions. And yes, I am firm in my
decision to have full field lenses.

What is an aphakic lens? Can you describe it and how it compares to a full field?
I know what a lenticular lens is, are they related/similar?

Thanks again :)

[John R]

eyedoc said:
Hi,

I'm getting new glasses.
My RX is 11.00 in both eyes, no astigmatism.

I guess you mean +11.00.
If you want any sort of curve on the back then you will really need to consider 1.7 index if you really want to stay with glass.
I recon if you stay with std index, if you put a -6.00 on the back the front will be around +16.00. Which will not look nice at all in a large frame. Even in HiIndex you are still looking at a front of 13.00 ish. But the weight is going to be bad...
To be totally honest even though glass is better in your RX i would go for plastic.
That from a guy who has done glass for 27 years...

[Texas Ranger]

eyedoc,
assuming that you have an average PD of 64mm, have an +11D lens ground on an 11 bc, a frame ED of 58, you'd need a 70mm blank, considering a 0 edge thickness, you'd have a center thickness of 15MM; so in a glass lens, how is weight a non-factor.? suppose you'd get a new style frame in a 48-20, instead of a 56-20, your lens thickness would be 7.7MM, and not have to deal with the negative affects of the thickness magnification factors, the "non-issue" weight factor, reduced chromatic aberration and marginal astigmatism, and what an improved cosmetic affect!!

[Texas Ranger]

eyedoc,
assuming that you have an average PD of 64mm, have an +11D lens ground on an 11 bc, a frame ED of 58, you'd need a 70mm blank, considering a 0 edge thickness, you'd have a center thickness of 15MM; so in a glass lens, how is weight a non-factor.? suppose you'd get a new style frame in a 48-20, instead of a 56-20, your lens thickness would be 7.7MM, and not have to deal with the negative affects of the thickness magnification factors, the "non-issue" weight factor, reduced chromatic aberration and marginal astigmatism, and what an improved cosmetic affect!!

[eyedoc]

Yes, +11.00, no astigmatism. By the way, my PD is 71.

John R and Texas Ranger, thanks for your input and answers,
Your info is exactly what need. Please enlighten me with
your knowledge. Remember, I'd like a bit of knowledge, too.

Please help me fill in the blanks. I will provide two different
scenarios for two different frames, a size 48 and a size 57.
Both must be glass, full-field lenses.


Scenario: Frame 57
-------------------------------------------------

- Lens thickness
- Lens thickness compared to plastic lens
- Weight of lens pair (not including frame)
- Weight of lens pair compared to plastic lens
- List material and technique/approach you would take: grinding, blank size, etc (for glass only)
- Your comments


Scenario: Frame 48
-------------------------------------------------

- Lens thickness
- Lens thickness compared to plastic lens
- Weight of lens pair (not including frame)
- Weight of lens pair compared to plastic lens
- List material and technique/approach you would take: grinding,
blank size, etc (for glass only). Please expand on this, and if
possible provide descriptions of technical "stuff"
- Your comments


All your responses have been most helpful, you are sincerily appreciated.

[hcjilson]

Aphakia is the absence of the crystaline lens.Aphakic lens would be used in treatment of this condition.It can be full field or lenticulated. With the introduction of IOL's in treatment of cataracts these lenses are becoming less common although there's still plenty of them out there.

Have you considered getting an eyelash curler?

In jest from Cape Cod from harry j

[Jeff Trail]

First you do NOT need to even consider "glass" as in crown glass..to thick and to heavy to even make it an option, next high indexes, they have no base curves available in the upper indexes that will give you what you are looking for (more ocular curve)
As for the questions of weight and thickness.. you need more numbers than just the eye size and PD to figure that out, you have to have the B measurement (vertical from the lowest point in the frame to the top) the ED diagonal measurement at a 45 degree angle ..and the bridge. THAN you will have to have the exact base curve and material information to put it all together. :-)
An aphakic lens is a design where you have a "bubble" in the center of the lens (called the bowl) it is 35 to 40 mm across and a thinner area on the edges called a carrier ... this lets you use only the center to carry the power and the edges are not as thick so it ends up being lighter...you have two choices of Lenticular's, a regular Lenticular where the bowl edged is very distinct and a supermodular where the bowl comes down and "blends" into the carrier...you have a choice of SV and ft's...
I would throw the glass stuff out if I were you not even an option, to much weight... throw out high index as well if your whole reason is you stated is finding a lens that is not as "flat" on the ocular side ... check with the supermodular aspheric lenticular and the full field cr39 lens... you want to start with a 14 or 15 base lens and work your way up... the more front curve you get the less flat it will be on the back..
BUT (always a but some where it seems) if you are used to having worn those flat curves on the inside you may not want to get to much curve you'll have a hard time adapting to the new spectacle magnification and distortion ... you may want to do this in jumps..say increase no more than a couple diopters over the next few changes in lens till you reach a comfortable vertex distance you wanted...

Jeff Trail

[John R]

If you need a 65 m/m std index glass lens it will be 12.8 thick.
If you need a 55 m/m std index glass lens it will be 8.7 thick
Now for 1.7 index
If you need 65 m/m it will be 9.0 m/m thick
If You nedd 55 m/m it will be 6.3 m/m thick
but bear in mind hi-index glass in denser so weighs more.

If you take the 1.7 index lens with a front curve of +10.00 you would have a back curve of -2.00 which should give you enough lash clearance unless you have real long lashes. Now i'm gessing you live in the states so the lenses would require toughing which is going to add to the thickness by about half a m/m. There is a fourmula for working out weight but i do not know it and as i said at the top a lot more information about the frame is required shape as well..
You could try a 1.66 index plastic lens which would have around the same thickness as the glass hi-index but would be far lighter.
From personal experiance i know how heavy glass is to wear, i'm only +6.00 in one eye and i can no longer stand wearing glass all day. I was worried about the change to plastic lenses but can say that you wont be able to tell the diffrence wearing them apart from the fact you dont have two big dents in your nose at the end of the day.

[Texas Ranger]

eyedoc,
in my earlier post, I made some "assumptions". like your pupillary distance, and mechanical frame pd.(distance from center to center) i.e, if you have a frame that is 56mm eye(at the vertical mid-line) and a dbl (distance between lenses), your frame pd will be 76mm. so I used 64mm pd(distance between your eyes). that's a difference of 12mm; 6mm each eye. I made the assumption that you didn't get a round frame, so the ED(effective diamiter) was 58mm(an arbitrary # for this example), so, if you happen to has a 76 pd., your lens would be 8.9mm thick, if your pd is 64, and you didn't decenter them, you'd looking through about 13D of base in prism!, so, it's now wise to decenter in 6mm, right? if you decenter in 6 mm, you'll be 6mm short of filling up the whole frame with glass, so how large an uncut blank do you need? add the ED to two times the decentration(since blanks are round and the 6mm has to be added to both sides of the blank, so the uncut needs to be 70mm, and a +11 70mm blank has a vertex depth of 15mm; youu cound switch to plastic, but they'd still be quite heavy. strong spherica lenses that size do "induce" marginal astigmatism and chromatic aberration, so in reality it's the lens size that is the problem. if you know your real PD and can calculate the real ED, etc. as in the above example, the center thickness will be 15mm, the outer edge will be 0mm, and the nasal edge about 9mm; ugly glasses, heavy, magnifying; all relative to what you COULD have in that 48mm lens! unless you change the eyesize, plastic lenses won't help; another thing, the smaller lenses need to be in an adjustible pad frame that can be adjusted to fit further away from your lashes, which means you'll also likely need to make a vertex power adjustment..IMHO.
PS>>>>it's also not unheard of to AR coat glass lenses! it helps a lot...

[John R]

Texas Ranger said:
it's also not unheard of to AR coat glass lenses! it helps a lot...

If you are going for Hi-Index glass then its really a must..

[eyedoc]

I have narrowed it down between this two frames:

1. MONSIEUR
Mens Model 101/F, flex sides, size 57-17.

2. Wall Street
Milton Appel Optical, very classy, size 56-20.


My decision to have glass lenses stands. Whether or not I get
my lenses with a curved or flat back (ocular side) will depend on
how much I can learn from you guys and my ability to communicate
this info and my specifications to the folks making my glasses.

One important note you could provide for me:
Take the frames listed above, and describe the outcome glass lenses:

Conventional, flat ocular side Vs. My ellusive curved lenses

Please tell me if there would be any significant price differences
between the two options, both glass, of course. If possible, provide
some $figures, in US$, however rough they may be.

[hcjilson]

First you ask for advice. You come up with a bizarre set of requirements for your glasses. Some pretty good people spend some time on your problem and work out a plan for you , while at the same time answering some of your questions so that you will be an informed consumer.You got the advice you asked for, then you say regardless of the advice you're still sticking to the archaic reqirement of glass. If you are going to be that inflexible, why do you ask for advice?

In most of our offices, the customer does not design the lens, .....we do! If you really want to learn how to do it, become an eyecare professional.

I sense our collective legs are being pulled, and if that is NOT the case please accept my apology along with the only advice you should take. Get an eyelash curler and have your glasses made as soon as possible any way you want them.
Best from Cape Cod Harry J

[chip anderson]

I can see Harry's point of view. But if you must have +11.00 spectacles and insist on a heavy weight material. Get something in a 46, or even down to a 42 eye size. The specifciations you ask are going to look like George Burns after catarac surgery.

Smaller= thinner and lighter. No matter what you may believe you cannot see any more centrally or peripherally out of bigger lenses with a +11.00 Rx. I still think your best answer is to get some contact lenses you can wear all your waking hours. If you can't do so with your present ones, they don't fit.

Chip

[John R]

eyedoc said:
Whether or not I get
my lenses with a curved or flat back (ocular side) will depend on
how much I can learn from you guys and my ability to communicate
this info and my specifications to the folks making my glasses.

Ok best frame is No 1 as it should give you thinner lenses, albeit by a tenth of a m/m....
As to whether of not you get the lenses you want is not down to you but the lab who will be making them. As its all going to depend on what product ranges they stock.
Please take the advice offered and get a smaller frame after a day of two you will not notice the diffrence (except for your nose that is).
Sorry but you will not get any prices offered as each provider is going to have their own ideas on what to charge and its not our place to say it will cost $xxx when you eyecare provider might decide its going to be $yyyy.
I agree with Hj you came looking for advice which was freely given yet you choose to ignore this advice and still plough on with your own path...Please think again about what you need. Make a change in you glasses you wont reget it.

[kjw1231]

You might consider laser surgery to correct at least part of your +11.00 and no astigmatism. In Canada and Europe there are procedures to correct Farsightedness. I had a friend who eliminated his need for bifocals with this procedure. He had it done in Toronto for $500.00, which can be cheaper than glasses.

Check with an Ophthalmoloist and see if this is right for you. Even if he corrects it partially, your glasses will come out more presentable.

[Texas Ranger]

Yep, and you could not used sun protection at the next eclipse, waste your lenses, have implants put in and you'd be thrilled, except maybe, if you don't time it right and get corneal burns, or glaucoma from the implant operation, but I guess you could follow up with a corneal transplant, just please don't get those monster big frames...