Q. Tinting Reader Lenses
We are using Hilco's new EqualEyes� readers and have a patient who wants his readers tinted. Is this possible? Also, how do EqualEyes readers differ from basic drug store readers?--Derek Tong, O.D., Southern California College of Optometry Clinic, Fullerton, Calif.

A.
EqualEyes are currently available in acrylic and polycarbonate, both with a super scratch coating applied. The coating will not accept tinting. The difference between these new reading glasses and drug store readers is that readers have the same power in each eye, while most patients require different corrections in individual eyes. Also, PDs are typically fixed at 64mm, regardless of frame size. PDs should, however, vary with frame size for greater wearing comfort. The EqualEyes system provides 10 different lens powers (including plano) to make it possible to offer patients any number of combinations, to match the Rx requirements of each eye as closely as possible.--Bob Woyton, product manager, Hilco

Q. Are AR and Polycarbonate Compatible?
I read a lot about AR coatings on polycarbonate lenses, and I am well aware of their benefits. There seems to be one drawback, however, at least if my lab is to be believed. If the AR coating is compromised in any way by scratches or otherwise, it cannot be removed because the removal also eliminates the underlying scratch resistant coating on the lens, and thereby ruins it. Is this true of all lenses and all removal methods, or is my lab misinformed?--Ernest V. Loewenstein

A.
Many times AR can be successfully stripped from polycarbonate lenses, but there is sometimes a problem. If done carefully, the only problem is not removal of the scratch coating, but damage to the scratch coating. This damage shows up as a cloudy appearance. It doesn't happen every time. Also, if an acid bath is used to remove the AR coating, any remaining acid after the treatment must be removed carefully and neutralized. Otherwise, the subsequent AR coating may not adhere properly. Success with this remedy seems to rely on careful processing and a lot of luck. It is not advisable to apply this removal technique multiple times to the same lenses.

When a blemish occurs during normal AR processing of poly lenses, most coating labs will attempt to remove the AR and recoat, since the coater is responsible for replacing any blemished lenses. They have nothing to lose by attempting the removal. Most problems with cloudy scratch coating occur on the front surface, which has a factory-applied coating. Knowing about this potential problem, your lab may not feel it's worth the risk.--Edwin Ellefsen, Opticote, Inc.

Readers Respond
Here are two tips offered by Eyecare Business readers in response to recently published questions.

PAL Markings: A recent column addressed removing progressive lens markings. At Eyemart Express in Tulsa, we recommend using a non-acetone nail enamel remover. It works well and quick for us.--Evelyn Johnson, Eyemart Express, Tulsa, Okla.

Loose Screws: I have some information to help the optician who wrote about loose or lost screws. What we do at our shop on every pair sold or repaired is use clear nail polish on the screw heads and ends. It is strong enough to hold, is hardly noticeable, and the screw is easily broken free under the force of a screwdriver when needed. It is a cheap and fast way -- usually three minutes to dry -- to avoid loose screw problems. It eliminates later having to search for uncommon screws as well as stocking a large and sometimes costly screw inventory.--Chris Ely, ABOC

Q. A Piercing Question
I have been working with polycarbonate lenses in Mexico for two years and am having problems with drilled lenses. Some of the lenses we drill are cracking around the hole after they are used. Could you suggest a technique to solve this problem?--Carlos Becerra, lab manager, Mexico

A.
Place the lens with front facing the drill bit and slowly operate the drill through the lens. Trying to push a drill through polycarbonate will actually push material out through the backside. To avoid this, it is best to drill down 1/2mm at a time, back the drill out, let it cool several seconds, and then continue -- 1/2mm at a time. Back the drill bit out of the hole often to remove any cutting debris that, if left there, will increase heat damage. By slowing down the process, you avoid melting the material and end up with a clean drill hole. Poly cuts best with a sharp burr, operated at low speeds of 20 to 60 revolutions per second and with minimal to moderate pressure. Twist style drills cut less aggressively and often leave subsurface damage.--Polycarbonate Lens Council EB

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