contact lens care
Caring for GP/Soft Piggyback Lens Systems
BY MICHAEL A. WARD, MMSC, FAAO

Silicone hydrogel materials are revolutionizing the soft contact lens industry. As a group, these materials offer superior oxygenation to the cornea, perform well in dry eye conditions and are associated with a lower incidence of microbial keratitis.

Silicone hydrogel lenses have also dramatically increased the success of piggyback lens systems. Today's piggyback lens system employs a silicone hydrogel lens as the base soft lens on the cornea (for comfort) and a GP lens on top (for better vision).

Older piggyback lens systems using HEMA-based soft lenses had limited success largely because of barrier-induced hypoxia. Using silicone hydrogel soft lenses with high-Dk GP lenses has proven quite successful, particularly for use over irregular corneal surfaces.

Knowing What Products to Use

The major brand multipurpose soft lens care products are approved for use with all soft lenses including silicone hydrogel soft lenses. Alcon's Opti-Free Express carries specific indications for use with silicone hydrogel lenses. CIBA Vision's hydrogen peroxide-based Clear Care is indicated for all soft lenses and is also approved for GP lens disinfection and its Focus Night & Day lenses.

Simplicity remains the key for patient compliance in lens care. Yet using two different contact lens types in a piggyback system necessitates using more than a one-bottle care product. In general, you can use any product labeled for use with soft lenses for GP contact lenses; the reverse, however, isn't true. Many GP products can cause irritation, burning and epithelial corneal damage if used with soft lenses. Because GP contact lens comfort is highly dependent on lens cleanliness, have patients use specifically formulated GP contact lens cleaners.

In my experience, the following combinations of lens care products are clinically successful when used with silicone hydrogel/GP piggyback lens systems:

MPS-Based Lens Care (Note that CIBA Vision's Solo-care can cause lens parameter changes and is specifically contraindicated with Vistakon's Acuvue Advance silicone hydrogel lenses.) When using this type of care regimen, follow these steps:

• Remove and clean the GP lens with a GP daily cleaner (Boston Advance Cleaner [Polymer Technology Corp.], Optimum Extra Strength Cleaner [Lobob]). Thoroughly rinse the cleaner off of the lens as directed.
• Store the GP lens in a soft lens multipurpose solution (MPS)
• Remove and rub/rinse the soft lens with an MPS
• Store the soft lens separately in soft lens MPS
• In the morning: Place soft lens and GP lens on the eye. Use MPS or aerosol saline if desired
• Rinse lens case and air dry

Peroxide-based Lens Care Follow these steps for this kind of piggyback lens care regimen:

• Remove and clean/rinse the GP lens using a GP daily cleaner.
• Store GP lens in peroxide disinfection system according to product instructions
• Remove, rub, rinse and store the soft lens separately in a peroxide disinfection system according to product instructions.
• In the morning: Rinse soft and GP lenses or place both on the eye. The GP lens surface may not wet properly when taken directly from the peroxide care system. Use a soft lens MPS as a wetting agent for the GP lens before placing it on the eye.

Don't use GP wetting/conditioning solutions with a piggyback lens system. Complete Moisture Plus (Advanced Medical Optics) is the thickest MPS and works well as a wetting agent for placing the GP lens over the soft lens

• Instruct patients to rinse the contact lens case and allow it to air dry daily/scald weekly.

Mr. Ward is an instructor in ophthalmology at Emory University School of Medicine and is director of the Emory Contact Lens Service.