Zeiss Individual distortion?

[zdawg]

I have a customer who had been wearing a bifocal for years, but was tired of the limitations of a bifocal; she wanted to see intermediate zones and does a lot of editing, but also wanted a general all purpose lens to meet her needs. In October she chose to go with a bifocal and we put her in the Varilux S Series with default measurements (we do not have a fancy digital measuring program at this point).

She had a great initial response but complained after 2 weeks that there was not enough room in the reading portion for her to read a book, and that she wanted to get another pair of glasses with a wider reading corridor. We put her in the Zeiss Individual 2 N (again with default measurements)...she has had these for 3 weeks and says that her S series is clearer and there is too much distortion in the reading portion of her new glasses...she compains everything curves abnormally in the reading portion...a bit of a fishbowl effect...

we had her come in and took all the measurements (back vertex) with the tool Zeiss sent us to have them redone to her specifications but I am concerned this still won't work for her. Should I put her in a different lens design? Why do these issues seem more extreme with the variable corridor lenses than with conventional PALs (ie Physio)?

her rx: +1.50-0.25x125, = 1.75-0.25x060, +2.00 add ou.

thanks for the help

[sharpstick777]

Putting one patient in two different designs is always very tricky, it can be done, but not everyone can adapt. I have worn a ton of lenses and go back and forth well (except for my Essilor FF).

The first thing you need to do (with any visual problem) is verify Near and Distance VA against the chart, or use a trial frame or flippers. You could be under corrected in the reading and barking down the wrong hole, wasting a lot of time.

In the "S" thread here on Optiboard, there are quite a few people who report small reading in the "S" series.

With two different FF designs, you are sending a lot of different math to her brain, and the BCs on both lenses will be very different. Resulting in fishbowl effect if one is "prefered" by the visual system. It doesn't mean its a better lens, just adapted to.

If you can verify both the reading and distance VA is correct, then consider refitting her entirely, by lifestyle. The "S" has narrow reading, but if she wants to stay there and "Office" or Computer typle lens would better partner better with that lens for reading. The Definity 3 would be an alternative to the "S" with a ton of reading, but is similar to the "s" in some ways.

The Individual is a T shaped progressive, wide on top, narrow in the intermediate, with a slightly wider reading. Its primarily distance emphasized even in all derivatives Its a great lens, but it stays clear in the distance as the add power increases, getting harder (which means the corridor is never super wide) . There are lenses with wider corridors even than with "Intermediate" or "Reading" derivatives of the Individual, (you did order the "reading" version didn't you?).

Fitting the Individual to a patient who needs a lot of reading, is like having a patient complain that the sports care they have is too small, like a Porsche Boxter, but selling them only a slightly bigger sports car, like a 911. They simply may need an minivan or SUV for their needs.

Personally, I would refit the "S" lens, keep the Individual Reading, and pair that with either an Office type lens, the Seiko Surmount WS, or the Definity.

[EdgeOptical]

or do the individual again, but with a lower seg height fitted higher... if that makes sense.

if the real seg height is 18mm, have it made as a 14mm, fit at 18mm. so its a more compressed int. area, and larger reading.

i havent heard complaints about the individual with distortion in the reading, so that kind of stands out to me.

with the individuals on, add a quarter in the reading, see if it improves... thats odd.

[sharpstick777]

I think you mean with a internal shorter corridor length, but fitted at the same seg height, no? bringing the reading up higher. Its a good option.

or do the individual again, but with a lower seg height fitted higher... if that makes sense.

if the real seg height is 18mm, have it made as a 14mm, fit at 18mm. so its a more compressed int. area, and larger reading.

i havent heard complaints about the individual with distortion in the reading, so that kind of stands out to me.

with the individuals on, add a quarter in the reading, see if it improves... thats odd.

[Robert_S]

Bear in mind that many of our customers often mean a completely different thing to what we think they do. When she says 'narrow' she may well mean 'too low in the frame'. Bifocal wearers are used to having a very accessible reading zone, so I find when switching them to varifocals, a short corridor makes it much easier for them to adapt. And, since you opted for standardized measurements, Zeiss most likely set the reading area right at the bottom of the frame. Given the Rx, the patient should get excellent performance from a lot of different designs. Just make sure to use a harder design so it isn't too different to the bifocals she's used to. Physio II short should do the trick, sure. I can say with confidence though that the design of the Individual won't be an issue, particularly since you chose the near version.