.25 cyls What's your opinion?

[Jane]

What's the point of a .25 cyl?

If anyone has an opinion on this subject, I'd really like to hear from you. Or if someone can direct me to an existing thread, that'd be great.

I'd like to hear from Dr's & lab techs, opticians, the whole kit-n-kaboodle.

[Rich R]

I think a .25 cyl is not necessary, but that's only my opinion.
Rich R.

[Jeff Trail]

Jane,

This subject can get very convaluted and murky ;) A few key phrases and words that you will see a lot is the type of astigmatism ...simple, compound and mixed. Than you will see how it ties into direct (with the rule), indirect (against the rule) the focal lines and the circle of least confusion.
Now involving visual acuity in astigmatism, small amounts of astigmatism (.50^less) does NOT have a bearing on "visual acuity", there is NO distance that an uncorrected astigmatic person has sharp retinal image. BUT if one or both of the focal lines are behind the retina "simple or compound hyperopic astigmatism" visual acuity CAN be improved to some extent through accommodation so that the "circle of least confusion" coincides with the retina ..now if the focal lines (one or both) are in "front" of the retina "simple or compound myopic astigmatism" accommendating will move the circle of least confusion away from the retina causing more blurring ;)
So depending on the type of astigmatism, the axis a quater CAN be helpful...

NOW as a lab owner, do I always like grinding a .25^? NOPE, a pain in a high myopic RX especially in mid and high index materials. Do I ever tell an optican to "drop" a .25 cyl. NOPE, unless you have access to a lane and know how to refract better not tinker..
I think that if more people in our business cross trained more and took classes in refraction they would understand this a lot better.. notice the other thread "should opticians refract" IF you do not understand this question you asked and know why or if you should RX a .25 cylinder than YOU do not need to be refracting :finger: (not you "jane" but you as in "whoever" )

Simple ..

Jeff "lab rat...still" Trail

P.S... Laurie (on this board) teaches refraction as part of the A.S degree she might have a lot more to offer on this subject... I'm just a lowly lab rat :D

[Excel-Lentes]

Hi,

My Rx has a .25 cylinder. I have tried wearing glasses with and without it. Jeff is correct in regards to affecting visual acuity/ the .25 cylinder does not help me achieve more lines on a snellen chart but I can see things a little bit sharper. The "E" looks like an "E" with or without the cyl. but looks a little more defined with the .25 cylinder.

I should mention that I wear stock lenses. I have noticed with surfaced products .25 cylinders sometimes are not that helpful. I have seen .25 cyls. off axis, strong, weak and downright distorted with surfaced lenses.

[JRS]

Just because the lens is surfaced, does not diminish the need (when requested) of the .25 cylinder. Some labs have trouble producing minor cylinders in certain materials. Therefore, they don't like doing them... and constantly downplay the need for it.

I too, as Excel-Lentes, wear a quarter cyl in one eye (.75 in the other). Makes a difference to me when it is negated or incorrect.

[Jeff Trail]

JR,

Was in one of "those labs" the other day trying to do some trouble shooting and asked about when was the last time you trued up your laps.. "you need to do that?" ... needless to say that answered my question....
If they learned to adjust the stroke on the cylinder machines it sure would help getting that smaller cyl. to come out ..most people don't know you can change the orbital radius of the stroke.. tsk tsk...
I know I went into the "medical" side of it but I still like the version I used in retail as well... "your distant correction is your fine tuner and the cylinder is your sharpness button "

I will agree with you though "most" lab guys hate low cyl. but to them it is just a pain and does not seem to do any good, other than to increase your breakage.... MAYBE more lab guys need to come out into the light and learn some of the medical stuff as well.. the new poll is "should lab guys refract opticians who want to refract" ;) get your own secret undercover decoder "trial lens set" ring... just like a box of cracker jacks...

Jeff "what light breaks through yonder polymethyl methacrylate"Trail

Gee I have become such a cosmopolitan fellow as of late..

[John R]

JRS said:
Some labs have trouble producing minor cylinders in certain materials. Therefore, they don't like doing them...

Sorta right the problem with High Index materials is a 0.25 cyl is...

• 1.7 = 0.19
• 1.8 = 0.16
• 1.9 = 0.15

Now unless labs go to the expense of cutting tools to create a correct 0.25 cyl in each index. You can see the problem, as there is no way the customers will pick up the cost of a tool.

[Tim Hunter]

From an optometric viewpoint (rather than a lab rat) 0.25 cyls are prescribed not because they "are there" but because they make a subjective difference to the patient's vision and visual comfort. If you want to get technical they would create a small blur circle on the retina if they were not corrected and can cause asthenopia (symptoms of eye strain) in some patients. Some patients don't appreciate them, some optometrists don't pick them up! but I have certainly had patients who notice the difference without them.

[chip anderson]

I have seen some folks that a .12 cylinder helped, sometimes a lot more than I thought it could. But most of the time I think .25 cylinders (especially when this is the complete Rx) are precribed to up the price.

I have seen a few individuals many years ago that would Rx a .12 cylinder [with no sphere in Rx] in a pair of welding goggles (in these cases I was shure that the it was added to up the price and the precriber owned a piece of the dispensary.)

Chip

[Blake]

I suppose even 0.25D can make a difference, but what about tolerances? For example, a 0.25 cyl would also be acceptable as 0.12 or 0.37 cyl. Also, with a 0.25 cyl the effective power is only varying by +/- 0.12 between 0 and 180 degrees.

[Jeff Trail]

John R said:
Sorta right the problem with High Index materials is a 0.25 cyl is...

• 1.7 = 0.19
• 1.8 = 0.16
• 1.9 = 0.15

Now unless labs go to the expense of cutting tools to create a correct 0.25 cyl in each index. You can see the problem, as there is no way the customers will pick up the cost of a tool.

John,

One of the reasons a lot of labs have starte converting to laps in 10th's instead of 12th's .. as the index of refraction available to us has expanded we kind of have to rethink our processing.
A big plus as well to getting and maintaining the correct power is in the laps, BUT having a good generator never hurt :-).. the problem I see most often in keeping correct powers in low RX's starts at the blocker (heat) and the generator is calibrated but the run time and air pressure and laps defeat the curves cut when it makes it to the cylinder machine...
I still have a lab I went into about a dozen times to find the problems and more or less tell them the same thing.. they run the blocker at around 130 degree's and run every lens the same way on the cylinder machine..28lbs of pressure!! and run the first fine for 2 1/2 minutes and the second at 2 minutes and polish for 6 minutes!! YIKES
I go through and adjust it all and get it back to where it needs to be and even post big boards up so all they have to do is look up and it lists the run times and pressure...go back and they are all back to doing it the old (wrong) way..what are ya gonna do..sheesh.. as long as they keep wanting to pay me I'll keep going back and changing it and posting the directions again :-)
Unless you get a system like DAC has that has a "flexiable" lap system I don't think we ever will have the "correct" tools all the time, to many different base curves and index combinations to make it a "one size fits all" ... check out the new system from DAC.. it's pretty neat...

Jeff "we few, we brave, we optical rats" Trail

[aaron]

No doubt most people would agree that from an actual dispensing aspect each individual patients tolerance will vary excedingly from one another. One patient will probably swear by that .25 while someone else would absolutely never be able to tell the differance. And as strange as it may seem I have worked with doctors who will even prescribe a redo with only a quarter diopter change. I used to dismiss the patients newfound appreciation for their Rx as a "mental" thing. However, there have been cases that have convinced me otherwise. So since it is impossable to gauge someones sensativity when they walk in the door, I think it would be better to remain exact as possable. And that would include that .25 cyl.

ad................

[Jane]

I know I'm going to be sorry for saying so but I can get out of tol. on the same lens my peers can get within, and vice versa. When I see one of them back for a remake I want to go hairy carey. Maybe I should restrict myself from checking axis on these. Consider it self preservation. Particularly on a progressive lens, or this photochromatic 1.56 I just received back to credit. Maybe I just need downers to get me through some of this stuff but crediting a couple hundred bucks on a .25 cyl that's 10 off. Somebody help me justify that PLEEEZ.

Just venting.

[John R]

Jane said:
I know I'm going to be sorry for saying so but I can get out of tol. on the same lens my peers can get within, and vice versa.

Jane, dont worry as we all see / perceive powers etc diffrently. In fact we have 3 focimeters and we can get diffrent reading on all of them....(Dont mention calibration, i dont want to go there)
In fact if you have one of the auto ones you can make them read what ever you want.....

Dont think of " hairy carey" Just smile nicely and say looks alright to me.....

[JennyP]

We are a (mostly) one hour lab.
Speaking about getting "in" and "out" of tolerance by two different people: sometimes one or two in my lab will try to tell me that a lens is fine when I think it isn't, so I say, "Ok, but are BOTH lenses fine on this pair with your equipment?" They try to tell me that the left lens is ok on one focimeter, and the right on another, but I don't let them get away with that. Thankfully it doesn't happen that often.
What really irks me is when a tech is getting ready to go home and sends out a job 90 degrees off or with a surface scratch. I think they should admit the error, even if they can't stay to fix it, rather than letting the job sit for awhile when it could be corrected. On the retail side, we may be so slammed with lookers and buyers that the messed up pair doesn't get inspected for 20 to 30 minutes.
To the lab techs, I am just a "dispensing" optician and can't truly appreciate all the difficulties involved in producing that perfect pair. (Yet, I am the one who has to explain to the patient that his/her pair didn't pass inspection and that there will be a longer wait.)
The lab techs who have my greatest respect are the ones who come find me/or call me back to the lab as soon as they know an order will be late, letting me know why and how long to fix the situation. That way I can meet the patient as they come in, or better yet, call their cell # to make them aware of the delay.

[Jubilee]

Jenny!

What we have been doing at our store is setting a "quality binder" up at the retail checkout station. It is a just a small binder with a tab for each of our lab inspectors with lined paper. That way if any "issues" come up on a pair and it needs to be either taken back to the lab, or if retail has to fix the alignment, or any other problem..it can be noted in that person's section with the rx#and the problem. It also is a place where complements can be written down as well so it isn't all bad news. At the end of the week, we look at this binder and we can see what associates need training in what areas (even if it is attitude) and what we are doing well in. So far it is really working well. It takes a couple of moments to document, but on the other hand it is worth it to take care of the problems. :bbg:

On the other hand it really gets irritating when the 1st inspection lensometer reads about one degree and .12 plus more than the 2nd inspection lensometer and then the Reichert reads a degree off from it! So when you have that pair that gets kicked for being 3degrees off axis on a 5.75 cyl, you can understand it..but it really is frustrating....and it is even more frustrating when a dispenser sees "marks" in the lens, but no one in the lab, not even the RQC or the ADQA can see them..but they insist they are there!!!!


As for .25 cycls.. yeah they are the one pain in my.. well you know ..for manufacturing. I now have a fix for the poly problems we were having, evidently the .12 diff between base and cross wasn't enough. If I bump the lap to a full.25 then the full cyl is in there and my axis in on. Previously I wasn't getting a full .25 and my axis would seem to be about 30 degrees off...

The only material I have problems with .25 cyls in now is Ormex..But we have other issues with it as well. Lots of distortion the closer you get to the seg...I know heat is a factor..but I can't seem to get it any better no matter how much I play with my settings.

Cassandra

[Rich R]

Cassandra, one of the reasons the area right above the seg line is more abberated is an issue with blocking since there is an air gap created by the tape between the block and lens in that spot, might help if you try smoothing the tape down to eliviate that problem.
Seems like your store works well together to fix all the problems, that's a big plus to make work better for everyone.
Rich R.

[Jubilee]

Don't know about everyone else in my lab..but I do smooth as much as I can that air bubble created where the tape goes over the seg. It is somewhate better than not..but I still get a good 5mm worth of distortion. Really bothers me..

And as far as my store..yeah it is a good store :bbg: It took us a year to get this far. Our turn over last year wasn't the best, (my regionals brought it to my attention that it was around 100%). In fact I have been in this store for a year and two months, and all of the faces have changed a couple of times in the lab except the other Asst lab manager. While I didn't want to see two of the seven people who left go, I am very happy that we seemed to have upgraded to people who want to be there and want to do the job well. I have flat out told the people I work with that I (being the workaholic I am) spend way too much time at work to be constantly dealing with bad attitudes and those who can do nothing but grich. If you can't have fun and get the job done, then just go home and begin looking for another place to work...

When you have a lab that really is looking out for quality and getting the majority of the jobs done right and on time, it goes a real long way for the retail and dispensing staff to actually work with us as well. I don't know how many hours I spent when I first was promoted to that store, talking with EVERYONE about what was right, what was wrong, how can we work together and get this store to work.

I am very proud of how much we have accomplished. We recently placed 14th in the midwest. That is a long way from the bottom that we started out in. The team is working well, and it is finally beginning to show. Our key internals are up and so is our checks :D

So thanks for the compliment!!!

Cassandra

[Jeff Trail]

Cassandra,

Nice to see that you have moved the store quality onwards and upwards .. but you might as well get used to high turn over, I know a LOT of lab people and have trained a "few" in my years in the field and one thing I have learned is not everyone is cut out for lab work no matter what you do.. oh some can do it but if the speed is turned up it's like a "switch" gets thrown and the quality goes out the window.. while some the faster you go the better they are, but when you slow down they make mistakes :-)
The biggest problem I have, and you'll end up having, is once you train people they get taken away once you get a reputation for speed and quality.. it's a two edged sword, I do not really hold it against anyone to always want to move up and do better but half the people in this town I have trained using my lab and teaching them and they moved out..I did start a program (don't think it will work for you though) a few years back where I will let people rotate staff into my lab, the OD's pay them but I help train them.. it has worked so well that the OD's have started rotating some opticians and techs as well in for a three or four week crash course.. I know they all think that it has improved their sales and the moral in the practice and they have a better understanding of the "lens" side as well.. I know in 3 or 4 weeks they couldn't be let loose on their own and mass produce but still it has been very helpful in the communication between the lab and the practice...
BTW one thing you might want to check on the Ormex (and spectralite if you are running it) is the run times and the air pressure on the cylinder machines..these two products are VERY sensitive to heat and picking up wave distortion from the laps..you can NOT run them the same way you run CR39 in the cycle..
Also if your cylinder machine is slightly out of calibration these materials pick it up, and the result is off axis power problems and waves.. you have the axis blocks and check the cylinder machine, right? :-)
Just a couple of places where I see a lot of labs make a boo boo running this stuff...

Congrats on moving your lab quality up.. I know how frustrating at times it can be..

Jeff "Tis the season to be poly..fa-la-la-la-la-la" Trail