SPECIAL ANNIVERSARY SECTION
10 Contact Lens Highlights from the Last Two Decades
BY DESMOND FONN, DIP OPTOM, MOPTOM, FAAO
In honor of Contact Lens Spectrum's 20th anniversary, I present "Desmond Fonn's Top 10 Highlights from the Last 20 Years of Contact Lenses."
10. Lawsuits Patent disputes within the contact lens industry have been a frequent news feature. Imagine what could have been accomplished if the money spent on legal fees had been spent on research and development!
9. Multipurpose Solutions Hydrogen peroxide disinfection of soft lenses 'ruled the roost' until multipurpose disinfecting and cleaning solutions emerged in the early '90s to effectively corner the market with one-step simplicity.
8. The World-Wide Warehouse: Contact Lenses on the Internet Sophisticated molding techniques for soft lenses facilitated high yields at reduced unit costs, allowing the sale of lenses to shift to suppliers other than traditional eyecare practitioners.
7. Microbial Keratitis: An Enduring Problem Up to two-thirds of cases of corneal infections in U.S. and U.K. hospitals were contact lens-related. This rather dramatic rise in incidence of microbial keratitis (MK) was linked to the increased popularity of contact lenses in the '80s. Reports of corneal infections, in addition to the work of Poggio and Schein, demonstrated that both the incidence and risk of developing MK increased significantly with extended wear.
6. Re-emergence of Orthokeratology The most important development in rigid lens design was the reverse geometry concept which, coupled with over-night wear, enabled corneal reshaping to re-emerge with some success. Unfortunately, reports of MK have created concern about this procedure.
5. Critical Oxygen Transmission Holden and Mertz demonstrated that lens-induced corneal swelling was avoidable if the lens has a Dk/t value of 24 during open-eye wear and of 87 during closed-eye wear. This landmark finding helped steer the course of development for silicone hydrogel technology.
4. Extended Wear Extended wear (EW) gained popularity in the United States once the FDA approved 30-night continuous wear of soft contact lenses in the early 1980s. In response to reports of MK in the healthy eyes of EW patients, the FDA shifted approval from 30 nights to six nights only. EW was discouraged throughout the '90s until the introduction of high-Dk/t silicone hydrogel materials, but it appears that the incidence of corneal infection has remained the same.
3. Contact Lens Dropouts We've known since the early '90s that patients all too often discontinue lens wear prematurely because of discomfort, which is still an enigma.
2. Disposable Lenses Mass production in concert with the knowledge that wearing aged and soiled lenses causes ocular complications resulted in the development of frequent replacement and disposable lenses.
And the Number-one Highlight of the Last 20 Years...Silicone Hydrogels The developers of silicone hydrogel technology take my prize for the most significant contact lens development in the last 20 years. Hypoxia-free wear for almost everybody even during EW is a major milestone.
What Didn't Make My List?
You might argue that my list should include toric soft lenses, keratoconus research, imaging systems such as corneal topographers, the International Association of Contact Lens Educators (which won CLS's 'Event of the Year' a few years ago), the slow demise of GP lenses, competition (or lack thereof) posed by refractive surgery and more. I welcome your thoughts on my list.
Dr. Fonn is professor and Director of the Centre for Contact Lens Research at the University of Waterloo School of Optometry in Waterloo, Ontario, Canada.