Strange but True: You can easily remove most scratches from 1.60 and 1.66 product

[harry a saake]

wax

I can't find my notes from school. What is the refractive index again of Johnson floor wax?

years ago i worked for your basic shyster type lab owner, and we always had a large can of johnsons wax to fill in scratches, it will get them out of the lab, until they get washed a few times, nobody knows

[Chris Ryser]

You can also cover the fine hairline scratches with Lens Renew, which is a humidity cure polymer and it will fill and cover fine hairline scratches permantly.

[Nikolay Angelov]

A lab here offers this service (for a fee) for lenses they make:

They strip the AR and hard coat, and coat the lens like if it's just surfaced (apply new hard coat, new AR, hydrophobic layers etc).

Most scratches are in the hard coat. Even if some shallow scratches are on the actual lens the hard coat fills them in and smooths the surface (as it does on FreeForm lenses).
They do it only on lenses they make, as they don't know the Hard Coat and other chemicals used on other lenses.

We have saved a few customers with damaged PALs that way.
The results were excellent, and the customer is happy to pay for a coating renewal (instead of complete new lenses).

[Chris Ryser]

A lab here offers this service (for a fee) for lenses they make:

They strip the AR and hard coat, and coat the lens like if it's just surfaced (apply new hard coat, new AR, hydrophobic layers etc).

Most scratches are in the hard coat. Even if some shallow scratches are on the actual lens the hard coat fills them in and smooths the surface (as it does on FreeForm lenses).
They do it only on lenses they make, as they don't know the Hard Coat and other chemicals used on other lenses.

We have saved a few customers with damaged PALs that way.
The results were excellent, and the customer is happy to pay for a coating renewal (instead of complete new lenses).

Nikolay, I have preached exactly the same thing here on OptiBoard for the last over 10 years. This is the way to do it, however on this continent most optician want to sell new glasses or at least lenses, and tell their customers it can not be done.

Besides that you could do the stripping yourself for somebody that has purchased new glasses and would like to have the old partially delaminated ones as a spare. It only takes maximum 10 seconds to stripp the AR coating and about 1 hour to get rid of the hard coat, and you have most probably a lens without even a scratch.

[Spexvet]

"Can't you just buff it out" heard a million times.

[Fezz]

"Can't you just buff it out" heard a million times.

Sure we can!

It will take a week to do and $487.33! How would you like to pay for that?

[Chris Ryser]

"Can't you just buff it out" heard a million times...............................

Spexvet, Pomposity! on my soapbox


"Can't you just buff it out" heard a million times.

This is continuing education with a childlike response where the subject has not sunk in and has triggered a sense of opposition.

Aristotle

[hcjilson]

Fezz is correct! Go with the flow....Sure we can resurface those- It will take about a week and the fee for doing it is 487.50 less, of course, your senior discount, of 48.75. The advantage to that is that they are able to "save" the old lenses thereby shorting the eyecare professional, and they are almost 50 bucks ahead of the game because of the discount!......When you get to be my age, you start thinking like a senior citizen! :):)

[RT]

For US labs/ECP's, Q20 of the 2010 FDA Q&A on impact resistance defines who needs to perform impact testing. Stripping coatings would most likely qualify as altering "the physical or chemical characteristics of the lens..." For example, if a lens had been rendered impact resistant by the application of a cushion coat which is then subsequently stripped away, the lens may not be impact resistant any longer. As such, anybody stripping or performing some of the other actions in this thread may need to consider testing for impact resistance.

http://www.fda.gov/medicaldevices/de.../ucm070579.htm
20Q. Who should perform the test for impact resistance?
A. The manufacturer must perform the test for impact resistance (21 CFR 801.410(d)(1)). Manufacturer is defined under 21 CFR 820.3(o) and would include the person (or firm) who puts the lens in the form ready for its intended use or who alters the physical or chemical characteristics of the lens by grinding, heat treating, beveling, applying scratch resistant coating, applying anti-reflection coating, cutting, or other pertinent actions.

[Dave E]

so when removing ar from a lens we are to check to see if a lens is still impact resistance that is if I under stand this right

[fjpod]

Ok, I'm an experiment junkie. I just conducted this with a 1.60 w/src only (no ar) stock lens I had. I used 1500 grit sandpaper to lightly scratch the front surface. ( it looked like very fine cleaning scratches.)

Still just as scratched afterwards as before the treatment described above. Common sense told me that the SRC was what scratched, not the material. If you could repair an SRC like this, it would work on any (or most ) SRC's.

So, not strange nor true.

Myth busted!!!

[Chris Ryser]

No chemical change......................

so when removing ar from a lens we are to check to see if a lens is still impact resistance that is if I under stand this right

Why don't you check your new fresh from the coating lab received lenses for impact resistance............that is where the major change to the material would have been made. Chemical wash cycle, heat to cure the hard coat and then the vacuum chamber for a double coating when a hydrophobic is added.

Removing an AR coating is purely a surface treatment, and nothing penetrates into the lens material, not even as much as tinting a lens. Furthermore there are also neutralizers available to get rid of any acid leftovers.

[Wes]

For US labs/ECP's, Q20 of the 2010 FDA Q&A on impact resistance defines who needs to perform impact testing. Stripping coatings would most likely qualify as altering "the physical or chemical characteristics of the lens..." For example, if a lens had been rendered impact resistant by the application of a cushion coat which is then subsequently stripped away, the lens may not be impact resistant any longer. As such, anybody stripping or performing some of the other actions in this thread may need to consider testing for impact resistance.

http://www.fda.gov/medicaldevices/de.../ucm070579.htm
20Q. Who should perform the test for impact resistance?
A. The manufacturer must perform the test for impact resistance (21 CFR 801.410(d)(1)). Manufacturer is defined under 21 CFR 820.3(o) and would include the person (or firm) who puts the lens in the form ready for its intended use or who alters the physical or chemical characteristics of the lens by grinding, heat treating, beveling, applying scratch resistant coating, applying anti-reflection coating, cutting, or other pertinent actions.

Aside from glass, (which you shouldnt try to strip since the stripper dissolves glass) most other lenses will be more impact resistant upon removal of AR, faulty or not.

[RT]

Aside from glass, most other lenses will be more impact resistant upon removal of AR, faulty or not.

The key word there is MOST. For example, some labs are able to surface 1.60 or 1.67 index materials to 1.0mm center thickness, by applying a cushion coat. Otherwise, those materials typically require 1.5mm center thickness to pass dropball. Strip a 1.0mm CT lens, and you may have rendered it weaker. Unless you have explicitly tested, you really don't know.

Note that the US FDA Q&A uses the word "must" with regard to who must test. Not "should", nor does it suggest an exemption for "most" lenses. You can interpret your own potential liability in the rare instance of a product liability case. Generally speaking, the last person to do something to the surface of the lens may be considered the manufacturer per the FDA Q&A. Certainly if you apply a coating, you are considered the manufacturer. It is less clear that removing a coating might also make you the manufacturer. As far as boiling a lens to repair a scratch per the original post...I wouldn't even care to speculate.

[hcjilson]

so when removing ar from a lens we are to check to see if a lens is still impact resistance that is if I under stand this right

With all due respect Dave, what does this have to do with the original question you posted at the top of the thread? Obviously the original premise is flawed! Why waste our time?