Rule of thumb for measuring 7/35 tri

[Kristen P]

where do you measure for a 7/35 tri. 1/2 way between the pupil and lower lid, or the bottom of the pupil?

[chip anderson]

I measure the bottom of pupil. Some older opticians (appearently there are some) split pupil.
Some (whom I concider backward and ignorant) put it at the lower lid to keep the patient from fussing about the line. Never mind the fact that they have to hold reading material on the breast .

Chip

[Judy Canty]

I'm with Chip on this one. I fit all trifocals at the bottom of the pupil. Always have.

[Happylady]

I was taught to fit at lower pupil but I have found that most patients perfer it lower. If they are happy with where they are wearing it now I put it in the same place. Otherwise I draw both lines on the glasses and make sure it is giving them enough reading without bothering their distance. This is usually about halfway between the pupil and lower lid.

[k12311997]

I measure the bottom of pupil. Some older opticians (appearently there are some) split pupil.
Some (whom I concider backward and ignorant) put it at the lower lid to keep the patient from fussing about the line. Never mind the fact that they have to hold reading material on the breast .

Chip

I was taught split pupil and given the choice that is what I do and make them wear them a month befor I'll even consider lowering it.

I usually see pt come in tri's at lower lid. the conversation usually goes something like this. me "your trifocal seems awfully low do you have trouble reading?" Pt " the last place made it higher but it really bothered me so they lowered it." me "how many days did you wear it." Pt. "none I just couldn't wear it at all" me " Ok I'll match were the line is." have 2/3 of the order written up. Pt out of the blue "you know sometimes I have trouble reading, Can you just raise the lower line?" Me note to self go home get drunk and forget today happened.

[rbaker]

Do you ever communicate with the client to assess such things as occupation and use of the eyewear? How about functionality of present seg height? Does posture or other anatomical considerations enter into the equation? Or, do you just apply some rule of thumb.

My primary lenses with a 3.25 Add are FT 7X28’s with the top of the intermediate fit at mid pupil. For desk and computer FT 7X28’s with the top of the intermediate fit at the top of the pupil. My sunglasses are FT 7X28’s with the top of the intermediate fit at the bottom of the pupil.

Do try to spend some time fitting us old farts; we need all the help we can get. Sometimes masking off seg height will help the customer decide on a good fit. But above all, remember this “you can not improve on an asymptomatic patient” so ask if the present she height is OK and if so don’t change it.

[HarryChiling]

A good thing to remember with tri's is to be very mindful of vertex distance. The closer the fit the closer to the lower pupil margin the patient can get used to sometimes even higher, but if the vertex is further out then usually the patient ends up liking it lower.

[cocoisland58]

I was taught to fit at lower pupil but I have found that most patients perfer it lower. If they are happy with where they are wearing it now I put it in the same place. Otherwise I draw both lines on the glasses and make sure it is giving them enough reading without bothering their distance. This is usually about halfway between the pupil and lower lid.

The correct way is lower pupil but you are right some people are used to wearing an incorrectly placed seg. I always ask them if they would prefer to keep tilting their head way back to read or would they like me to place it where it should have been placed originally. Most say to put it where it is supposed to be and like it that way. Even so I will most times keep it just slightly lower to accomodate the fact that they are usually older patients and have gotten used to tilting.

[ldyflsh]

I normally fit at the edge of the pupil...but if a patient uses a walker or a cane, I always ask the patient or family member if the patient walks with their head down (looking at the floor) I'll set it a bit lower to compensate.Same goes with a bifocal, I check the patient's "normal" head position.:o

[Kyle]

It's a pretty rare thing for me to fit a new tri wearer these days. I'm with everyone else - a fine merge between the ideal (rule of thumb bottom edge of pupil) and the practical (what is patient DOING while wearing - what is primary requirement of midrange).

2 cents = be aware of the patient's environment and make suggestions on how they could change it, and not just their glassses, to help them function better during their day. A patient who uses a desktop computer may experience neck problems moreso than someone with a notebook. Changing seg location isn't always the answer, in other words.

For many tri wearers (adds of +2.75 or higher) good lighting may be more of the solution, high reading contrast being the desired effect. Some older patients get confused with what part of the trifocal to use. Without proper lighting it's difficult for some to resolve the power change when moving through the segment. If whether you raise or lower makes little difference poor lighting may be the culprit.

k

:)

[Fezz]

All of this info and "proper" fitting heights is great, but, how many of these patients wearing the trifocals actually know how to use them? I have had so many patients over the years ask me "where should I be looking thorough, what part is for reading, blah, blah, blah". Most of these patients have been wearing trifocals for YEARS!!!!! Most don't have a clue!

[Andrew Weiss]

I was taught to fit them at the lower edge of the pupil. I was also taught to fit a bifocal at the lower lid.

So: the last place I worked in MA, where Uncle Fester still works, virtually every trifocal wearer was already fit at the lower lid, and virtually every bifocal wearer was fit 5mm below the lower lid.

For years, I thought the way I was taught was the way that works best for the patient's ease of use and vision (and, in theory, I still do). And for years (like 30+), my experience bore out that assumption. Working at Uncle Fester's place for 8 years was a weird experience: everything I assumed to be correct about bifocal/trifocal fitting was turned on its head.

In general, I'll take the "if it ain't broke, don't fix it" view with folks already wearing line-style lenses. For the others, I've become more flexible, and I look at the patient's work, hobbies, posture, physical abilities/disabilities, etc. While most of my new multifocal fits are progressives, I still do fit some new lenses-with-lines. For some folks, they just work better.

[Uncle Fester]

Andrew-So we still agree to disagree:D

I always felt I was fitting to just below pupil for tri. I also almost always put a small strip of cellophane tape at the height I want and then ask the patient to stand up and walk around. If they said it felt to high I'll explain the trade off in fitting it lower. In anticipation of the arguement that I should fit to where it's best for the patient and force them to wear it higher I'll politely agree to disagree:D:D (and not redo it 3 weeks later).

PS This held true between Andrew and me for progressives too. I found he was right 50% of the time but I was right half the time!!!

[Andrew Weiss]

Aw Fester, I measured them -- 5mm for sure:D:D

And thank you for introducing me to the Scotch-Tape method -- I still use it.:D

BTW, I still measure line-style wearers (as well as progressive wearers) sitting down and standing up -- and use whichever measurement is lower.

[optical24/7]

I fit tall patients lower and short patients higher, but match (usually) if the patient likes it where it was.