CONTACT LENSES TODAY
June 20, 2004
Contact Lenses Today® is edited by Dr. Joseph T. Barr and the staff of Contact Lens Spectrum. This week CLToday® reaches more than 10,000 readers in 74 countries.
Further Proof of the Danger of CL Wear Without a Prescription
Wong, et al. reported a case of severe bilateral deep stromal neovascularization and opacification associated with
unmonitored contact lens wear in a 46-year-old woman who, for five years, had been using hydrogel contact lenses that she had bought on the Internet
without a prescription. In the November 2003 issue of The American Journal of Ophthalmology, the authors reported that the woman's lenses were
tight fitting and she had dense, bilateral corneal opacities with deep stromal neovascularization. Medicinal history and serological studies were
negative for infectious or rheumatologic causes of interstitial keratitis. Because the authors believe that the deep stromal neovascularization and
the associated corneal opacification were most likely related to the unmonitored contact lens use and the lack of routine eye exams, they support the
need for all contact lens wearers to receive professional eye care on a regular basis regardless of where they obtain their contact lens supplies.
More Fruit, Less AMD
In a recent study, scientists found that people who ate at least three daily servings of bananas, oranges and other
had a 36% lower risk of developing age-related macular degeneration (AMD) than people who ate fewer than 1.5 servings a day. The study included
77,562 women and 40,866 men who were at least 50 years old and had no evidence of AMD. All participants completed questionnaires about their food
intake as well as vitamin and supplement use at different intervals. The scientists followed the women for up to 18 years and the men for up to 12
years. During that time, 329 women and 135 men developed early stage AMD and 217 women and 99 men developed neovascular AMD. The more fruit a person
ate, the less likely he or she seemed to develop neovascular AMD, but not early stage AMD. The scientists reported their findings in the June issue
of The Archives of Ophthalmology and also stated that of several fruits examined, oranges and bananas has the strongest association. According
to the scientists, they will need to replicate their findings and determine which component of fruit drives the risk.
Kelman to Replace Keefer
Replacing Phil Keefer as of July 1,
Naomi Kelman will become president of Johnson & Johnson Vision Care's
Vistakon, Americas, operation.
ADVANCETM Brand Contact Lenses with HYDRACLEARTM
three months after its national launch, ACUVUE®
ADVANCETM Brand Contact Lenses with HYDRACLEARTM
was already the second-most
dispensed brand (only behind ACUVUE® 2) in total and among new
wearers within the soft spherical market, according to Health Products Research.
success has been driven by ECPs
who have discovered that current lens wearers, dropouts and those simply
considering lenses – virtually all of their patients needing vision correction
– are responding positively to the enhanced contact lens experience delivered
by this revolutionary new lens.
VISTAKON will be showcasing its new generation in contact lens technology at the
AOA (Booth #s 401 and 301).
Is Where You Live Eye Friendly?
Acuvue Advance Brand Contact Lenses with Hydraclear has teamed with city study experts Sperling's BestPlaces to
determine "America's Best and Worst Cities for Comfortable Eyes." Using eight major categories, Acuvue Advance and Sperling's BestPlaces looked
at the 100 largest metropolitan areas with a combined population of nearly 180 million residents, or more than 60% of the U.S. population. Based
on input from experts at Vistakon and Sperling's BestPlaces, the two established the following criteria: altitude, sunny days, wind, extreme
temperatures, humidity, pollution, commute time and computer use and came up with the 10 best places for eye comfort. Here are the top five from
BEST PLACES FOR EYES
1. Tacoma, Wash.
2. Sarasota-Bradenton, Fla.
3. Charleston-North Charleston, S.C.
4. Mobile, Ala.
5. Portland-Vancouver, Ore./Wash.
WORST PLACES FOR EYES
2. Albuquerque, N. Mex.
3. Salt Lake City-Ogden, Utah
4. Wichita, Kans.
5. Las Vegas, Nev.
Paragon Expands Alliances, Celebrates Anniversary
Paragon Vision Sciences, Inc. has expanded its alliances with equipment manufacturers to further enable its customer base to have ready
access to topography. In addition to continuing its alliance with Carl Zeiss Meditec, featuring the Humphrey Atlas topographer, Paragon has entered into
marketing agreements with EyeQuip, featuring the Keraton Scout topographer; Marco, featuring the 3D Wave topographer; Tomey, featuring the RT-6000
Ref-Keratometer topographer; and Topcon, featuring the KR-8000PA Tri-functional autorefractometer.
In other company news, Paragon celebrates the
second year anniversary of earning the first FDA approval for overnight Corneal Refractive Therapy this month. Since the introduction of Paragon CRT
in August 2002, more than 2,000 eyecare practitioners have become certified to fit this vision correction option.
Time & Temperature Affects MPS Performance
Researchers set out to determine the effect of storage time and temperature on the efficacy of four multipurpose solutions
for soft contact lenses. They challenged aliquots of four multipurpose solutions, stored at different temperatures over a three-month period with contact
lens-related ocular pathogens, Staphylococcus aureus, Psuedomonas aeruginosa and Candida albicans. The researchers concluded that performance of
multipurpose solutions is affected by time and temperature of storage and that contact lens users should be aware that the efficacy of opened solutions
may not be sustained for as long as three months. They suggest that manufacturers reconsider their recommendations to further safeguard the ocular health
of contact lens wearers.
Leung P, Boost MV, Cho P. Effect of Storage Temperatures and Time on Efficacy of Multipurpose Solutions for Contact
Lenses Ophthalmic & Physiological Optics 2004 May;24(3):218-224.
LASIK Patients -- Or Not
A small proportion of our patients are serious about having refractive surgery. Many more are curious. Offer them new
technology contact lenses if they have failed with contact lenses in the past. If they dropped out, then new lenses that promise less late day drying
symptoms may help. Offer them CRT or overnight ortho-k -- the freedom of LASIK without the risks. And if they go ahead with refractive surgery, then
make sure they know that if they were a myope before refractive surgery, then they still are, and that dilated eye exams are important for their future
Peripheral Lens Systems
concept of edge lift in GP lenses is an important but confusing concept that we
should revisit. Both radial edge lift and axial edge lift are difficult to apply
clinically. However, there's a more practical approach.
I recommend the "Equivalent Bicurve" concept to evaluate peripheral
lens systems. The math is simple. Morton Sarver developed the formulas (shown
below) to calculate lenticular carriers on the front surface of firm lenses. The
same calculations could be used on the back surface.
If the total back peripheral curve sagittal depth is known, then Sarver's
Formula can be used to calculate the peripheral curve that matches this value
precisely! This allows one to compare and evaluate two multi-curve systems in
familiar terms (a radius and a width). This is helpful in fitting keratoconus
and other complex lenses, where frequent changes are necessary.
I no longer use axial or radial edge lift values in making clinical decisions
regarding changes in the peripheral curve system. I have copied these clinically
proven formulas of Morton Saver from my spreadsheet:
= Optic Zone Diameter
B7 = Lens Diameter
D12 = PC I Width B23 =
SAG of PC I
D13 = PC II Width B24 =
SAG of PC II etc
D39 is a formula fragment
D40 is a formula fragment
D41 is a formula for the PC radius of a bicurve
F51 is the sum of all the PC widths
D38 = SUM (B23..B27) .............Sum of all PC SAGs (to be matched with one
D39 = (2*D38 ^2+B8^2+B7^2)/8 ........ Sarver's (adapted from his lenticular
D40 = (B8^4-2*B8^2*B7^2+B7^4)/(64*D38^2) ..........Calcs
D41 = (D39+D40)^0.5 Bicurve
F51 = SUM (D12..D16)
--John C. Heiby, OD, FAAO
St. Clairsville, Ohio
See You At the Global Orthokeratology Symposium (GOS) This Week
(July 22-25, 2004 Toronto, Canada)
Learn how to manage and market your overnight orthokeratology practice.
Report adverse contact lens reactions here: http://www.accessdata.fda.gov/scripts/medwatch/ or call (800) FDA-1088.
Access a reporting form for
complications you've seen that were a result of contact lenses dispensed without a valid prescription at the Association of Regulatory Boards of
Optometry's (ARBO's) Web site: http://www.arbo.org/arbo.asp?dt=R&doc=Complications. Complete and send the form online or print it out and fax
it to (866) 886-6164.
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