SPECIAL ANNIVERSARY SECTION
- 20th
anniversary perspective
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.
Contact Lens Spectrum, Issue: June 2006