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Thread: How much distance area above fitting point?

  1. #1
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    How much distance area above fitting point?

    This is something I've been wondering about. I don't wear progressives myself so it's hard for me to judge. I fit Hoya Summits and Lifestyles. Average fitting heights of 21-25 in frame heights of 34-39mm (minimum B is 34mm).

    I always aim for at least 12mm between the top of the frame and the fitting cross. 12mm still makes me uncomfortable because it seems so cramped. 14-15mm seems ideal to me.

    If possible I adjust the frame. If a low-sitting frame can't be adjusted, my fitting depends on the corridor:

    - Long corridor: always center pupil, at least 12mm distance area. 14-15mm is optimal. If I have less than 12mm I inform the client about this. Less than 10mm is no sale.
    - Short corridor: at least 13mm because of the faster progression. Sometimes I fit up to 2mm below pupil center to get closer to 14-15mm above fitting cross.

    I get that some people can tolerate only 10-11mm of distance area but this seems incredibly limiting to me. I don't think you could even fit a big screen TV in that area. Driving must be pretty difficult. Riding a bicycle even worse.

    Any thoughts?
    Last edited by Airegin; 03-31-2018 at 03:48 PM.

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    This is such an interesting area of discussion.

    Personally, I fit frames and measure PALs similarly to the way you do. I'm also a big proponent of giving patients plenty of usable space for each of their 'zones' in PALs. That being said, I won't refuse a sale because of it, but I will explain in detail what the patient should expect out of their glasses and why I would or wouldn't recommend a certain solution.

    Sounds like you're doing a pretty good job though, you clearly understand the limitations of lenses despite not wearing them yourself.

    Might I ask if you're actually running into any issues fitting and dispensing PALs this way?

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    I've had no issues so far, though I know that most clients don't tend to complain as long as their PALs are no less than decent. That makes it really hard to figure out if I'm dispensing PALs that are simply good enough vs optimal.

    I've only encountered major issues when correcting PDs that were wrong on the previous pair. I can understand why some people get used to wrong PDs in SV lenses and even start to prefer the wrong PD but with PALs I don't get this at all.

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    Compulsive Truthteller OptiBoard Gold Supporter Uncle Fester's Avatar
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    I know Shamir's Workspace requires a 10mm space above the fitting height and I'd assume this is the bare minimum for all progressives as they know a thing or 3 about progressive optics;)

    But I must say I have seen and even fitted a rare few with less than this and they are perfectly happy.

    Are you routinely dropping the OC depending on pantoscopic tilt?

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    Quote Originally Posted by Uncle Fester View Post
    I know Shamir's Workspace requires a 10mm space above the fitting height and I'd assume this is the bare minimum for all progressives as they know a thing or 3 about progressive optics;)

    But I must say I have seen and even fitted a rare few with less than this and they are perfectly happy.

    Are you routinely dropping the OC depending on pantoscopic tilt?
    Should I? I always fit center pupil with long corridors (14mm), -1 or at most -2mm with short corridor (11mm) since I've rarely heard positive reactions with Hoya shorts at center pupil.

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    Quote Originally Posted by Airegin View Post
    Should I? I always fit center pupil with long corridors (14mm), -1 or at most -2mm with short corridor (11mm) since I've rarely heard positive reactions with Hoya shorts at center pupil.
    You are doing good to drop the OC on Summit and Lifestyle lenses. If you ever start using real freeform optics (such as Lifestyle 2), never move the OC off center pupil.

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    Quote Originally Posted by ThatOneGuy View Post
    You are doing good to drop the OC on Summit and Lifestyle lenses. If you ever start using real freeform optics (such as Lifestyle 2), never move the OC off center pupil.
    Do you mean only the short corridor (11mm) Summit and Lifestyle lenses, or the long corridors (14mm) as well? I haven't had any complaints with the long corridors at OC.
    Last edited by Airegin; 04-12-2018 at 07:48 PM.

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    I just checked the progressive glasses I have on- the fitting height is 22 and the B is 32. I don't find this limiting at all, there is plenty of distance area. Remember the add doesn't start at the fitting cross, it's just a reference point. I can easily see my 65 inch TV and drive. I don't use the progressives you mentioned but I suggest NOT dropping the fitting height. It messes with the intermediate and near quite a bit if fit too low.
    Last edited by Happylady; 05-03-2018 at 05:39 PM.

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    Quote Originally Posted by Uncle Fester View Post
    I know Shamir's Workspace requires a 10mm space above the fitting height and I'd assume this is the bare minimum for all progressives as they know a thing or 3 about progressive optics;)

    But I must say I have seen and even fitted a rare few with less than this and they are perfectly happy.

    Are you routinely dropping the OC depending on pantoscopic tilt?
    The Workspace lense is completely different- it's not designed to be worn all the time or for distance. With rare exceptions fit pupil center with progressives. I use a penlight and use the corneal reflex.

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    Quote Originally Posted by Happylady View Post
    The Workspace lense is completely different- it's not designed to be worn all the time or for distance. With rare exceptions fit pupil center with progressives. I use a penlight and use the corneal reflex.
    Will a laser also work?

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    Quote Originally Posted by Don Gilman View Post
    Will a laser also work?
    Hmmm, better stick to a penlight.

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    I've recently had quite some issues with short corridor id mystyles fit center pupil. Some clients tilt their head back and complain they can't see far. It's supposed to be like that but they can't let it go. One client complained about worse far vision while lifting her chin but at the same time attempted to see near while barely looking down. I guess some people just have unrealistic expectations.

    Today I had to fit multiple long corridor progressives at center pupil - 2/3mm (I'm not comfortable doing this to be clear) because they were very happy with their last pair which was fitted 4-6mm too low. If I fit at center pupil, I somehow expect complaints because they suddenly can't lean back and have to sit straight to watch TV. Am I doing wrong here?

    Also, what should I do if the vertex distance is only 8mm because of protruding eyes? I recently fit a myopic client like that with a short corridor id mystyle at center pupil fitting height (21mm with a frame height of 32mm). I hope that won't be a redo but I'm already expecting it will be. Should be a good learning experience at least.
    Last edited by Airegin; 05-16-2018 at 03:40 PM.

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    Quote Originally Posted by Airegin View Post
    Today I had to fit multiple long corridor progressives at OC - 2/3mm (I'm not comfortable doing this to be clear) because they were very happy with their last pair which was fitted 4-6mm too low. If I fit at OC, I somehow expect complaints because they suddenly can't lean back and have to sit straight to watch TV. Am I doing wrong here?
    In my opinion, no. You're not wrong. When I fit PALs, I actually typically fit slightly below pupil center. That being said, it's always important to remember that the patient sitting across from you is always priority number one. I've encountered some really weird stuff over my career, but it all boils down to what the patient likes best.

    I always start my interactions about lenses with patients asking what they like and don't like about their current lenses. It gives a nice baseline for where to start. And if they have their PALs fit way low and like it, I'm going to do the same. I will always discuss what exactly I'm doing and why with patients, though. So if I tell a patient that I'm fitting them lower than I typically would, they'll be aware of this, and it helps to curb those "I can't see and I don't know why" conversations.

    Quote Originally Posted by Airegin View Post
    Also, what should I do if the vertex distance is only 8mm because of protruding eyes? I recently fit a myopic client like that with a short corridor id mystyle at OC fitting height (21mm with a frame height of 32mm). I hope that won't be a redo but I'm already expecting it will be. Should be a good learning experience at least.
    Maybe someone can correct me if I'm wrong here, but I would think that the Rx compensation would account for this. I would imagine this would only be a redo if there's a specific need that isn't addressed with a typical fitting height and short corridor.

    Remember, everybody will have their own unique set of needs that may or may not change how you would typically fit a certain type of lens.

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    Quote Originally Posted by bretk0923 View Post
    In my opinion, no. You're not wrong. When I fit PALs, I actually typically fit slightly below pupil center. That being said, it's always important to remember that the patient sitting across from you is always priority number one. I've encountered some really weird stuff over my career, but it all boils down to what the patient likes best.

    I always start my interactions about lenses with patients asking what they like and don't like about their current lenses. It gives a nice baseline for where to start. And if they have their PALs fit way low and like it, I'm going to do the same. I will always discuss what exactly I'm doing and why with patients, though. So if I tell a patient that I'm fitting them lower than I typically would, they'll be aware of this, and it helps to curb those "I can't see and I don't know why" conversations.



    Maybe someone can correct me if I'm wrong here, but I would think that the Rx compensation would account for this. I would imagine this would only be a redo if there's a specific need that isn't addressed with a typical fitting height and short corridor.

    Remember, everybody will have their own unique set of needs that may or may not change how you would typically fit a certain type of lens.
    Thanks for the feedback. The client in this case always took off her glasses to read (all her previous glasses had 14mm corridors).

    I've been going through some older threads and apparently it's very common to fit Hoya progressives at center pupil -2mm (with both 11 and 14mm corridors). I just don't understand how lowering the fit on a 14mm corridor wouldn't cause significant issues for reading and especially computer use. Wouldn't you have to lift your chin way up to reach the desired add for computer?

    Even with 11mm corridors lowering the OC 2mm makes little sense. Might as well fit a 14mm at center pupil instead, no? I don't see the use of reducing pheriphal vision and increasing swim just to achieve that 1mm higher reading area.

    I would love some clarification regarding Hoya progressives with 14mm corridor (Summit, Lifestyle, id Mystyle).
    Last edited by Airegin; 05-16-2018 at 03:47 PM.

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    The feedback I've gotten from the patients I work with is that the slightly lower OC really reduces distortion, especially in the car. It's interesting though, because I very rarely get complaints with computer use or strain to read. I'm sure there's plenty of other Optiboarders who will look at me like I'm crazy, but I honestly can't explain it.

    The previous office I worked for I always fit progressives at pupil center without fail, and I had drastically more complaints about them in general. Go figure. Maybe it's a demographic thing?

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    What's slightly lower though? 0.5, 1, 2mm? Do you get good results lowering the OC 2mm on 14mm corridors?

    I have done a lot of center pupil fittings recently so the next few weeks should be interesting. So far I've had a few negative first impressions, more than I'm used to at least. Only short corridors id mystyles so far. I figured I could fit those center pupil as opposed to summits and lifestyles which I still fit -1 or 2mm. Looks like I was wrong and adjusting the frame to lower the OC 1mm/increasing panto doesn't seem to help that much. I know I shouldn't mess too much with pantoscopic tilt on id mystyles though, they are tailor made for the initial inclination value.

    I'm trying not to care about the higher redo rate but it's the only way to learn I guess. My redo rate has generally been quite a bit lower than most of my coworkers anyway.
    Last edited by Airegin; 05-16-2018 at 05:03 PM.

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    You must then ask yourself if what you THINK is below pupil is actually center pupil. Remember that Pantoscopic tilt effects the placement of a lens OC in relation to the pupil. Just a few degrees of tilt is effectively raising orl lowering the OC by a mm.

    Now if you are using POW to compensate for panto etc. and you fit lower than center pupil with say a lens compensated for a Panto of 2degrees your client will feel like the add power is much too low.

    Most lenses are defaulting at between 9degrees to 12 degrees of Panto. If you are using the default on the lens (or a lens that only uses defaults aka non POW optimized).

    Also Parallax error - it could be that we have learned tricks of "what works" for us. It might seem that you are dotting low but in fact we are dotting pupil center.

    I am measuring my seg heights with a perfect (close at least!) 180 degree line between us, if the patient is leaning, or slouching or otherwise dotting what looks like center pupil is actually dotting higher.
    Last edited by Tallboy; 05-17-2018 at 03:19 PM.

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    Excellent point, Tallboy.

    I'll add that to consider too finely the numbers often obscures the bigger picture. What looks good on paper oftentimes does not translate to the real world.

    What you have to consider is your patient satisfaction. Regardless of your redo rate, are your patients satisfied with the end results? If so, then you're doing it correctly. If not, then you should probably tweak your approach in some way.

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    Thanks Tallboy, some very insightful info there. Generally most of my clients are very happy. There are still some people with complaints though who either never return or end up thinking they can't wear progressives which I want to avoid.

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