SOLUTIONS: Working with PALs

Simple solutions to everyday challenges of working with progressive addition lenses

By Karlen McLean, ABOC, NCLC

New PAL technology abounds, and with it, ECPs face old and new fitting and dispensing challenges. A run-down of PAL facts will help you handle problems with these lenses on the front line.

Specialty tools and some ingenious practical tips can help solve pesky PAL problems. With all PALs, be sure to:

■ Ask or review written lifestyle questions to better customize PALs to patients.

■ Take measurements only after properly fitting the frame on the patient. With most PALs, set vertex distance at 12mm to 14mm and pantoscopic angle at 10 inches to 12 inches. Always follow manufacturer recommendations for vertex and panto for the best results.

■ Take monocular PDs using a pupilometer.

■ Take OCs with patient and dispenser in a comfortable sitting position. Center the fitting cross directly on the pupil.

■ Measure fitting height independently for each eye.

■ Review fitting guidelines for any PAL you fit and dispense and follow those guidelines.

Measure and fit PALs correctly for the best wearer adaptation and satisfaction. Images shown top to bottom: iZone from Opthonix, Office by Shamir Insight, and Varilux Ellipse from Essilor

IDENTIFYING PALS ACCURATELY

Knowing what you are working with is critical for successful PAL use. Consider the following methods for lens identification.

■ PAL identifier instruments provide a clear view of markings by using a backlight, filters, and magnification. Focus the device to ID PAL markings on glass or plastic materials.

■ The Optical Laboratory Association publishes "The OLA Progressive Identifier," a 38-page information piece that identifies over 300 progressive addition lenses. Each lens has an enlarged diagram with the location for the fitting cross and add power, available materials, and identifying symbol or company logo.

In addition, a new index created by the OLA groups lenses by recommended fitting height.

PAL SPOTTING

Locating PAL markings when devices and diagrams aren't available can be fairly simple. Try:

■ Breathing on the lens or otherwise steaming/fogging it carefully so the markings appear.

■ Using a hand-held magnifier against backlighting at close range.

■ Locating one mark, place the lens on a layout chart and look along the line where other markings should be.

■ Locating the temporal markings first. Depending on the lens size, shape, and PAL placement, some markings can get edged off, especially nasally.

■ Practicing PAL identification and becoming accustomed to those brands you dispense the most. Companies use varying technology and techniques to mark their PALs. Some are easily located while others are more difficult.

TAKE IT OFF

Remove progressive markings safely and efficiently with the following techniques.

PALs can be identified in many ways. Shown top to bottom: Succeed 1.67 polarized from Seiko Optical of America, Walman Optical's PAL, and Thai Optical Group X Minuo

■ Pens and liquids are available for purchase through optical manufacturers and suppliers. Research them before purchase to ensure they'll work safely with the lens materials and coatings you dispense.

■ Ask lens manufacturers for the proper marking removal techniques for use on all their products, preferably in print. Keep these recommendations posted in the lab and dispensary for easy, fast reference.

■ Soak lenses (not frames) in hot water for around 30 to 60 seconds to loosen the markings, wipe with a clean cloth, then if necessary finish with rubbing alcohol, ethanol, or methanol.

■ Carefully press cellophane tape on markings and pull off. Remove residue with rubbing alcohol, ethanol, or methanol. Do not use this method on AR lenses.

■ PAL markings on poly and polarized lenses have the reputation of being difficult to remove, as do some manufacturers' branded PALs. Using optical industry-appropriate marking removal pens or liquids on poly, polarized, and thick/dense markings usually works best to erase stubborn markings safely.

■ Use only clean cloths when wiping lenses, and try not to rub too hard or too often to avoid possibly scratching the lenses or compromising the coatings.

■ Home remedies should be used with caution. Non-acetone nail polish remover may require too much rubbing, which may scratch lenses.

Stripping chemicals found in paint and hardware stores may strip coatings. Acetone may crack or craze poly if it gets in drill holes or lens edges. Using butane or other removal liquids can work, but can also damage lenses, coatings, or both.

Heating lenses in a bead pan or hot air warmer to remove markings may overheat and damage the frame, lenses, or coating if left too long.

Properly fit PALs from the start for best results. Images courtesy of Carl Zeiss Vision's Brevity (left) and Optima's Resolution Response

■ Use cotton swabs for detailed marking removal. For example, if leaving the fitting cross and 180 degree marks on the lenses for verification on the patient while removing the rest of the markings for cosmetic delivery appeal. Use applicators with lots of padding so the wand doesn't inadvertently scratch lenses.

■ Buy marking removal products in bulk. Most have indefinite shelf life, and you receive a better price if you buy in larger quantities. Typically, these should be stored away from light and heat.

REAPPLYING PAL MARKINGS

Use the correct pen or marker for PAL lens material and coating application. Some recommendations include Sharpie Fine Point markers, Staedtler pens and markers, and China markers/grease pencils.

Line up verification stickers along the 180 degree marks and press stickers carefully onto lenses. Use a fitting chart or template if necessary.

As with removal methods, check with lens manufacturers for their recommendations for reapplying markings that are compatible with their PAL materials and coatings. EB