GP insights
Contact Lens Spectrum's 20 Years of GP Lenses
BY EDWARD S. BENNETT, OD, MSED

I want to congratulate Contact Lens Spectrum on 20 years of excellence in contact lens education and for its ongoing support of GP lenses. Initiated by Neal Bailey, OD, PhD, a hard lens advocate as well as a design, fitting and modification expert, and championed by Joe Barr, OD, MS, who has always believed that GP lenses have an important role in contact lens practice, Contact Lens Spectrum has been at the forefront of providing the latest information on GP lens materials, designs and resources.

An outstanding source of GP education is the archived articles on www.clspectrum.com. No less than 529 articles and columns featuring RGP lenses (before 2003) and GP lenses are archived and available on this site.

Contact Lens Spectrum has been an avid supporter of the contact lens industry. The Contact Lens Manufacturers Association (CLMA) and its educational division, the GP Lens Institute (GPLI), have greatly benefited from columns and articles featuring educational programs and resources from the GPLI and the benefits provided by CLMA member laboratories.

In August 2002, Boucher Communications, Inc. (now Lippincott Williams & Wilkins VisionCare Group) introduced the Global Orthokeratology Symposium (GOS). Attended annually by several hundred practitioners, this represents the largest GP-only meeting in the world. This year the Health Care Conference Group is presenting a "Fundamentals of Corneal Reshaping," Aug. 5-6 at the Southern California College of Optometry.

Manufacturing Advancements

Contact Lens Spectrum has reported numerous advancements in GP manufacturing, lens design and materials over the past 20 years. More advanced lathes have assisted the manufacturing of more consistent lens designs, resulting in well-polished edges, ultrathin constructions, aspheric and pseudo-aspheric peripheral geometries resulting in uniform edge lifts, a large reduction in initial non-wetting problems and improvement in the optical quality of toric and multifocal designs.

In 1986 there was still an emphasis on very low-to-medium Dk siliconeacrylate lens materials. These often exhibited problems with stability, wettability and, in some cases, corneal edema. Current second- and third-generation fluorosiliconeacrylate (FSA) or modified FSA materials combine high oxygen permeability with stability and good surface wetting properties.

GP Designs

Finally, the numerous advancements in specialty GP designs are noteworthy. Modern four- and five-zone corneal reshaping lens designs have greatly accelerated the time needed to reach the desired endpoint.

Successful aspheric multifocal lens designs with the ability to provide higher add powers are available, not to mention annular and segmented translating designs with intermediate vision correction. Large diameter GP lenses for post-surgical and keratoconus correction and reverse geometry lenses for post-refractive surgical correction have also become popular and successful. Via the Boston Foundation for Sight, scleral lenses in a hyper-Dk material have restored sight to many hundreds of patients who previously were visually handicapped.

What's Ahead?

It will be interesting to see what advancements in GP technology will appear in Contact Lens Spectrum during the next 20 years. Certainly, the contact lens industry is in its debt for being a leader in the worldwide education of contact lens practitioners.

Dr. Bennett is an associate professor of optometry at the University of Missouri-St. Louis and is executive director of the GP Lens Institute.