Contact Lens Design & Materials
What Are the Latest GP Trends?
BY RONALD K. WATANABE, OD, FAAO
In my August column, I wrote about fitting corneal GP lenses in this day and age when soft lenses “rule,” and scleral lenses seem to be the only hot GP lens topic. While it is true that soft lenses comprise the majority of the contact lens market, GP lenses seem to be alive and well, despite Dr. Nathan Efron’s 1998 prediction that GP lenses would be obsolete by 2010 (Efron, 2010; Bennett, 2011). Also, though fitting corneal GP lenses seems to have become less popular, they still have certain advantages over soft and scleral lenses, and some patients are more successful with and prefer smaller GP lenses.
What the Labs Say
I recently sent a short survey to several GP manufacturing laboratories asking them about recent trends in their lens sales/orders. As you might expect, their responses varied widely, but a few general trends were evident.
Spherical GPs Spherical corneal GP designs for regular refractive errors are in decline. Virtually all of the labs indicated that spherical lens orders are down. This is what Dr. Efron was referring to; regular refractive errors are now being corrected primarily with soft lenses due to many advances in soft lens technology, including better materials, better aberration control optical designs, more predictable and stable toric designs, and more consistent manufacturing. Soft lens fitting is fast and easy for most patients, and complimentary fitting sets allow us to dispense lenses immediately versus having to wait for a pair of GP lenses to be custom made. In the instant gratification society in which we live, this is no small thing. Yet, the labs reported that spherical GP designs ranged from 5% to almost 75% of their lens orders, with an average of about 45%, which is still a significant portion of their overall sales.
Specialty GPs Specialty designs are up. A few labs reported that multifocal orders are rising, likely because multifocal GP designs are still optically superior to soft designs. Multifocal fitting can be time consuming and frustrating, especially when the optics are “soft” and vision is not as clear as with single-vision lenses. GP multifocals can provide crisp vision more consistently than soft lenses can, and newer aspheric designs are relatively easy to fit.
Small-diameter irregular cornea designs are also increasing despite a general movement toward scleral designs. Perhaps more practitioners are fitting irregular corneas due to better designs, easier fitting nomograms, and better education. Or, it could be that more irregular cornea patients are being identified and educated on the benefits of GP lenses. Regardless, it is good to see increased use of these designs.
The labs universally reported that scleral lenses are on the rise. One lab that specializes in scleral lenses reported that sclerals comprise 80% of its orders. But for most labs, sclerals were reported to comprise only 2% to 10% of orders. So, it appears that while scleral lenses are increasing, they still have not taken over the majority of the GP market.
Finally, orthokeratology is also on the rise, though it is a small portion of most labs’ orders (2% to 10%), and some labs do not manufacture these lenses at all. One lab reported that 75% of its orders are for ortho-k designs. The labs that make these designs reported an increase in their sales.
What It All Means
It is encouraging that many categories of GP designs are increasing in orders and, presumably, fittings. Multifocal, irregular cornea, scleral, and ortho-k designs in particular will lead GP fitting into the future. CLS
Acknowledgement: I would like to thank ABB Optical Group, Art Optical, GP Specialists, TruForm Optics, Valley Contax, and Visionary Optics for participating in my GP survey.
For references, please visit www.clspectrum.com/references and click on document #239.
Dr. Watanabe is an associate professor of optometry at the New England College of Optometry. He is a Diplomate in the American Academy of Optometry’s Section on Cornea and Contact Lenses and Refractive Technologies and is in private practice in Andover, Mass. You can reach him at firstname.lastname@example.org.