Definity at 18, use short or regular?

[Happylady]

I am redoing a patient's glasses and am thinking about doing Definity Trivex. She was in Comfort Poly and complained about distortion in the distance area. She was wearing AO Easy before but complained about the near area. She tried trifocals in the past and disliked them.She has only one good eye so I want to use poly or Trivex.

Her distance is -1.50 -1.25 x75 with a 2.25 add. I am measuring her at 18. Should I go with the short or regular Definity? Another idea is the Physio in poly.

Any suggestions?

[HarryChiling]

I am redoing a patient's glasses and am thinking about doing Definity Trivex. She was in Comfort Poly and complained about distortion in the distance area. She was wearing AO Easy before but complained about the near area. She tried trifocals in the past and disliked them.She has only one good eye so I want to use poly or Trivex.

Her distance is -1.50 -1.25 x75 with a 2.25 add. I am measuring her at 18. Should I go with the short or regular Definity? Another idea is the Physio in poly.

Any suggestions?

I would recommend that if the add goes above a +2.00 use the short it will allow for more reading although it will compress the intermediate.

[Jubilee]

How much computer use will she be doing with them?

As Harry said, using the short will give her a larger reading area. However the compromise will be in the intermediate. If she works for extended periods of time on the computer, then perhaps the regular should be used to allow a more generous intermediate zone.

[Happylady]

She does a fair amount of both computer and reading. I have some Definity Short and find the intermediate to be quite good. The distance peripheral is important. I need a good distance area.

[Uilleann]

I've had better luck with the Physio design as opposed to the Definity on the whole over the past couple years. The Physio seems to be a slightly softer design over the Definity design and we have fewer complaints of distortion at all ranges, but particularly intermediate and near. It's also cheaper and has a 17 min seg as compared against Definity's 18 min. It will give a slight edge (slight!) if B size is a factor with your pt's frame.

The Physio 360 design is likely better than either the afore mentioned designs in any material, but will of course cost a bit more. Perhaps it's worth the cost if your patient is looking for the very cleanest optical design in an Essilor lens. Let us know how it works out when you get your choice back from the lab and pt's worn them for a bit!

[Happylady]

Okay, now I am second guessing myself. Maybe I should change it to Physio. The main reason I choose Definity is because of the Trivex.

She complained that her previous glasses and the new ones seemed "foggy". And since she has only one good eye and neck problems she does need good distance peripheral vision. I thought the Trivex might be better.

[KStraker]

You might also consider an Id Lifestyle cd in trivex.

[Uilleann]

Optically, we have had very poor luck with the performance of the Tivex/Trilogy/Phoenix material. Poly has served us very well without the ongoing difficulties of the other material. Visually, we have had no more problems with poly than with any other material and no greater increase in non-adapts. More so with the overall lens design than anything else. Best of luck whatever you choose to fit.

[Happylady]

Thank you everyone! I appreciate your help and suggestions.

[hcjilson]

I had a strikingly similar case in July, Definity's fit at 18 didn't go over well- changed her to Definity short and problem was solved. Re: Trivex, its the best spectacle lens material on the market. I just wish it was available in polarized.

[Andrew Weiss]

My rule of thumb on Definity is a minimum fitting height of 20. Below that, I usually opt for the Definity Short. I've used both, and while the short does have a slightly compressed intermediate and more peripheral "swim", getting a reading area that comes to the full add power at 18 high is usually worth the trade-off.

[EyeFitWell]

If it were me, I'd use the short and consider dropping to 17 to boot, giving her more distance w/o making the reading too far down compared to her old ones.
Good luck, tell us what you think!

BTW, I've had very poor results from the Physio and 360.

[Happylady]

If it were me, I'd use the short and consider dropping to 17 to boot, giving her more distance w/o making the reading too far down compared to her old ones.
Good luck, tell us what you think.

I ended up ordering the lens in Definity Short Trivex at 18 high. The Comfort she was wearing was at 19 so I did drop it but any lower would be too low.

I didn't go into a lot of detail in my first post because I was at work and busy but she is going to have an adjustment to any progressive. Her previous rx was about a -3.00 and for at least a year she was able to see as well or better through the sides and channel of the lens, since her new rx is about a -1.50.

Of course she couldn't read at all in them. But she kept wearing them and got used to it, she would pull them off for near. Basically, she was wearing a distance only lens.

Now she can't see well on the sides and she notices that she can't lift her head and see in the channel anymore. She feels the distance area is smaller and it is because the old glasses were almost all her distance correction.

To make matters worse, she has almost no vision in her left eye and has neck problems that make it hard for her to turn her head. :( A trifocal would probably be better for her, but she tried them before and disliked them.

I think when she gets her new glasses she is just going to have to wear them and get used to them. A second pair of distance only lenses might be a good idea for her.

[hcjilson]

I received this message from someone who lacked the common courtesy to identify themself but I thought the subject might deserve further discussion. The statement was this:

"Trivex as a material is no more "BEST" than anything else in a given situation. This comment is not only misleading, but patently false."

I only wish the author had pointed out what was misleading or false in the statement to which he took issue. If he or she cares to do that I am all ears.

I said it was the best material for the following reasons.
1. Optics
2. Safety
3 Weight= comfort

The is nothing misleading or patently false in those three atributes.

[HarryChiling]

I received this message from someone who lacked the common courtesy to identify themself but I thought the subject might deserve further discussion. The statement was this:

"Trivex as a material is no more "BEST" than anything else in a given situation. This comment is not only misleading, but patently false."

I only wish the author had pointed out what was misleading or false in the statement to which he took issue. If he or she cares to do that I am all ears.

I said it was the best material for the following reasons.
1. Optics
2. Safety
3 Weight= comfort

The is nothing misleading or patently false in those three atributes.

The message didn't come from me but it is correct in that trivex isn't the best material only in some scenarios. That being said Fezz has turned me into a true believer (well that and the price coming down). :cheers:

[Fezz]

That being said Fezz has turned me into a true believer (well that and the price coming down). :cheers:

See..................the Kool-Aid taste great!


:cheers::cheers:

[HarryChiling]

See..................the Kool-Aid taste great!


:cheers::cheers:

Yeah a little like almonds, but it makes me sleepy. :cheers:

[Uilleann]

...I said it [Trixex] was the best material for the following reasons.
1. Optics
2. Safety
3 Weight= comfort

The is nothing misleading or patently false in those three atributes.

Please back up this statement and these three claims with facts. We'd all appreciate it and be wiser for the knowledge.

[EyeFitWell]

Please back up this statement and these three claims with facts. We'd all appreciate it and be wiser for the knowledge.

1. Lower ABBE value than poly.
2. Impact resistance on par with polycarbonate.
3. Lower specific gravity than poly.
(I think it was assumed that we knew that)

[Fezz]

1. Lower ABBE value than poly.
2. Impact resistance on par with polycarbonate.
3. Lower specific gravity than poly.
(I think it was assumed that we knew that)

Actually higher than poly!

We knew what you meant!

;):cheers::cheers::cheers::D

[optical24/7]

Please back up this statement and these three claims with facts. We'd all appreciate it and be wiser for the knowledge.

Mr Jilson is way more than capable of answering himself, but I'll contribute...

One of the most important aspects of a given lens material is it's dispersion which is specified by it's Abbe numbers. The lower the number, the more chromatic aberration. C.A. becomes more noticable to the patient when Rx's are high, OR off axis viewing. Abbe values as high as 45 can be noticable to the user in a lens larger than 40mm dia. Thus, the higher the Abbe number, the less likelyhood a patient will have C.A. related problems with vision.

Now the, Abbe numbers for our commonly used materials...

Crown glass.............59
CR39.......................58
Trivex.....................43
1.60.......................36-42
1.67........................32
Poly.........................30

Abbe effects on chromatic aberration are estimated to change 1:1, meaning a change from 30 to 32 would have hardly any noticeable difference. ( hence why I don't like 1.67 anymore than poly). But a change from 30 to 43 would be noticeable, especially in higher powers/off axis viewing.

As eyefit says, Trivex is on par with poly on impact resistance and has a lower spacific gravity than poly, it's lighter by unit mass. Thus more comfort to the patient.


ps eyefit...we want High Abbe's :cheers:

[Fezz]

Now the, Abbe numbers for our commonly used materials...

Crown glass.............59
CR39.......................58
Trivex.....................43
1.60.......................36
1.67........................32
Poly.........................30
:cheers:

Isn't that 1.60 higher now? Something like 40-42?

;):cheers::cheers::D

[Fezz]

Isn't Trivex more scratch resistant than poly?
Trivex doesn't suffer from hole elongation in rimless mounts like poly does it?
Isn't Trivex much more chemical resistant than poly?

[optical24/7]

Isn't that 1.60 higher now? Something like 40-42?

;):cheers::cheers::D

Depends on if it's MR10 or MR8 material. You're right that most are using the MR8 now that has a 42 Abbe number.

[Fezz]

Does Trivex *Spider Crack* like poly?

Doesn't just about every chain store, Budget-Mart, and Cheat-the-Public-o-Rama, dispense poly?

Would using Trivex instead, educating the patients, and heavily promoting it, differentiate your practice?