Progressives- Larger Depth Frames- Less Distance Vision

[Optikal]

Hello

Hope everyone is well, have been having a few issues with customers with larger depth frames

Particularly with customers who have a very low ditance rx or plano rx with a Add.

Frame size depth is 30 for example and height is 20 or 23, heights are taking accurately but it seems blurry to the customer like they don't have enough distance room on the top.

Is it advisable to lower the height by a few mm's, would that increase distance vision?

Anybody run into this problem because the frame depth is very deep and the customer needs more distance than reading

I'm a noobie and english isn't my first language so forgive me if my english is off or haven't worded it correctly

thank you

[optimensch]

depends what you mean by "a few" millimeters!
it is advisable to try to accommodate your client's needs, and if the distance vision is inadequate, then sometimes yes, you lower the seg a bit.....imho

[optical24/7]

You don't want to drop the fitting height on most modern PAL lenses. They are optically designed for proper, center pupil fitting. These newer PAL's are designed around center of rotation of the eye. By fudging the fitting location you are messing with the design's intentions and delivering a lens not as designed for optimal use at most angles of view.

With a complaint as above, I would re-frame style if I couldn't adjust the frame properly. Welcome to OB!

[Java99]

I would not lower the seg height. I would switch to a better designed lens.

[standarduck]

They fitted correctly, but are blurry in the distance?

I'm not sure those statements can be true, unless there's also a problem with the Rx. How are they being fitted?

30 is not a deep lens. Most PALs require 10mm at the top as well as room at the bottom.

A 23 fitting height in a 30mm deep frame doesn't offer this. - choose a deeper frame, and make sure all staff know these kind of requirements to avoid patient disappointment.

[Optikal]

Thank you everyone for your replies. We will not lower the heights if that's not recommended.

Unfortunately choosing another frame isn't a option either.

A lot of frames have the same issue, the bottom portion of the lens is very deep, I know that's the current trend- B size upto 36 And what not.

Will put them in another lens design.

One quick question, if the seg height is marked at 22 and frame depth is 30, does that mean the distance portion is only 22mm-30mm?

[Optikal]

They fitted correctly, but are blurry in the distance?

I'm not sure those statements can be true, unless there's also a problem with the Rx. How are they being fitted?

30 is not a deep lens. Most PALs require 10mm at the top as well as room at the bottom.

A 23 fitting height in a 30mm deep frame doesn't offer this. - choose a deeper frame, and make sure all staff know these kind of requirements to avoid patient disappointment.

So what your saying is if there is a frame that has a 30 depth the maximum height should be 20 or the customer will encounter problems?

[standarduck]

So what your saying is if there is a frame that has a 30 depth the maximum height should be 20 or the customer will encounter problems?

They COULD encounter problems - it's not definite (and also depends on other stuff too). A lot of the PALs I fit have some small mention of having 'enough' space at the top of the lens. How much this is will be open to interpretation, but I normally like to have 10mm where possible.

[Craig]

Thank you everyone for your replies. We will not lower the heights if that's not recommended.

Unfortunately choosing another frame isn't a option either.

A lot of frames have the same issue, the bottom portion of the lens is very deep, I know that's the current trend- B size upto 36 And what not.

Will put them in another lens design.

One quick question, if the seg height is marked at 22 and frame depth is 30, does that mean the distance portion is only 22mm-30mm?

I am guessing the power in the distance is not exactly what they want. I tried a pair of Hoya lenses recently that where the new super duper and they where 0.20 strong according to their own compensated rx over what it even said; being a low minus the lenses where the only pair I threw away.

Low power folks are very picky about unwanted power above the 180.

Go to a low compensated lens in trivex for problem solved unless RX is just wrong for pt.

[standarduck]

Go to a low compensated lens in trivex for problem solved unless RX is just wrong for pt.

Why would Trivex (or any other material, for that matter) solve this problem? It's (most likely) a fitting issue.

[Robert Martellaro]

Maybe two issues?

If from the client's perspective, they are seeing, or are bothered by the top of the frame in their field of vision, follow optical24/7's recommendation, find a frame with a better bridge fit so that the frame vertical mid-line (datum) rests slightly higher, increasing the vertex distance as little as possible.

The other problem seems to be blur on the primary gaze. This is a more complicated issue, and may be due to progressive lens design, pupil diameter, individual sensitivity, add power or changes in add power, vertex distance, etc. Even when optimally fitted, some folks will still experience some softening of their distance visual acuity that should resolve with time. Hypersensitives will have to abandon progressives altogether, and/or multifocals of any type, wearing two or more pairs of single vision, but that is rare.

I would start by reviewing the progressive design(s) that you are using, specifically the zone width at the fitting point (wider is better), and the power ramp up at the upper end of the corridor (lower/longer is better).

[sharpstick777]

Its the brand/type of lens you are using I bet. I would find a distance emphasized lens, and recommend fitting a corridor based on Add Power not on frame B measurement. It will give you good distance, an appropriate reading height and stable usable intermediate in between.