Almost Always . . . with good success
Almost Always . . . with questionable success
Sometimes . . . on problems with proven success
Almost never . . . little success
Never . . . not worth the labor/effort
Question for Labs with Surface Rooms
Do you "rework" your lenses when you encounter problems such as: swirls, poor coatings, prism, scratches, thicknesses, waves/abberations, etc? If so, what do you consider to be your success rate? IOW, do you feel it is worth the time and labor to attempt to "fix" a lens? Or, do you find most attempts result in other problems such as off power, etc.
Any comments or experience would be appreciated.
It all depends on the material. As long as you have the thickness to be able to rework, cr39 should be no problem. Poly, high index & mid-index rarely have ever came out ok after being reworked,,at least for me. What are having to rework your lens for?
Paul:cheers:
LOL . . . "swirls, poor coatings, prism, scratches, thicknesses, waves/abberations, etc" :o
Anybody can make a mistake, have a lens not come out as it should,Originally Posted by stargazer
But
it is un-excusable in this profession to pass on a lousy job to a patient who is paying (usually top Dollars) to receive a prescription that contains only one of the items in above quote.
If you can not re-work the job supply another lens.
:finger: :finger:
Sorry if my post suggested that the choices were rework or pass. The main point was to find out: rework or remake. For every job "reworked" a new job gets pushed back only to find out that the rework resulted in an off power job, etc which then would result in a remake anyway. Make sense?
We are simply trying to establish if the practice of "rework" is a common one, or if most labs just post breakage and start over.
<<Sorry if my post suggested that the choices were rework or pass.>>
Your post seemed clear to me, stargazer. CR is adding a bit of conspiracy into a straight forward question.
You raise an interesting business decision question. Hopefully others who surface will respond.
We usually never resurface lenses, the only exceptions I can think of would be lenses that were special orders ( not a stock item ) and the patient has to have today, or plus rxs that have some thickness that may stand up to the heat of reblocking. Thin centered minus lenses most often show waves in the center of the lenses created by the heat of reblocking. Pull new lenses and start over its not worth the time and effort in most cases.
Mike
We usually try reworking a lens if possible.
Unless there is a considerable amount of money at stake I dont bother reworking. Generally you will waste time reworking only to start from scratch and make a new one wishing you'd done that in the first place.
As previously mentioned however plus lenses with a reasonable centre thickness yield good results.
Rick
We usually rework the lens. Swirls, pits, backside scratches, etc, all those can normally be taken care of with a refine/repolish. Even some slight axis issues can be taken care of. If it is more than a couple of degrees of axis outside of tolerance, or if prism is an issue, we will reskim the lens too. WE generally aim for the center of the thickness tolerance, so typically we have a bit of room to play with there. When we reskim, we try to get a clean backsurface as to not produce any waves. The only material we have problems reworking is ormex.
Cassandra
Few years back there was an optical store in Harlem that wanted to introduce one hour service on their customers.
The Doc saw the patient, changed the Rx by 0.25 or 0.50 than they revorked patients old lenses and since in + they became a bit smaller they just put some more washers in the frame and gave the NEw RX to the customers.
They was almost a line outside. most of them were Medicaid patients ! :drop:
The important thing is that the finished product meets standards. If you can "re-work" it successfully, you have saved yourself the cost of a lens blank. Whether that is worth the extra time involved depends on a lot of factors. We usually try to "save" a breakage whenever possible, but our volume allows that - a busier lab may not have that luxury.
As long as the lens comes out perfect or within tolorence we always try to rework the lens. Most of the time you should be able to save it if not then you just start over.
A good profit margin for a big lab is 4%. Please define top dollar.
I apologize, I have been there and I know that.
I am under the impression that this thread deals with a surfacing room which I assume is a retailer doing surfacing next to his cut and grind. Therfore my remark of top Dollar
Not the case . . . perhaps I lacked detail, but not sure that it mattered.;)
it cost to much time to redo surface lenes the chances are to high and time consuming get a new pair lens started . it is less expensive to make. your chances are very slim on redos 98% failier rate so if you have another pair get them started and larn from the misstake.
oh yeah... I'll resurface a lens that isn't quite right, but only if there is enough size and thickness to do so (usually I add a little extra C.T. to jobs I know might be a problem), otherwise I take the hit and use a new blank. Fortunately for me, I rarely have any problems to begin with... but in answering the question(s) asked at the top of this thread:
Do you "rework" your lenses when you encounter problems such as: swirls, poor coatings, prism, scratches, thicknesses, waves/abberations, etc? Yes.
If so, what do you consider to be your success rate? not sure about an actual quantity, but I know failure is rare ;)
IOW, do you feel it is worth the time and labor to attempt to "fix" a lens? Or, do you find most attempts result in other problems such as off power, etc. yes, b/c most times the problem is fixed and you would have spent the same amount of time pulling a new lens, when you could have done it with the old one (assuming it is able to be "saved").
Last edited by eromitlab; 12-29-2004 at 08:27 AM.
Most SV and ST (or "D") type lenses are inexpensive and not worth the labor to try to save. (You'll double your labor cost to save $1.50 worth of poly material?) But some of the progressives and High index lenses are quite expensive to replace and worth the gamble. You'll need .3mm of thickness to refine and polish, and usually don't have that much left (especially on minus lenses). Every rejected lens has to be analyzed to see if a salvation attempt makes good sense.
shutterbug
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