CONTACT LENSES TODAY
April 29, 2007
Contact Lenses Today® is edited by Dr. Joseph T. Barr and the staff of Contact Lens Spectrum. This week CLToday® reaches more than 12,000 readers in 74 countries.
May is Healthy Vision Month
The National Eye Institute observes Health Vision month in May, an annual observance designed to raise awareness of the importance of eye care for those at risk for developing eye and
vision problems. This year’s observance highlights the importance of early glaucoma detection. The NEI is encouraging patients to get a dilated eye exam and to spread the word to family and friend using its e-cards
and brochures. For more information, visit http://www.nei.nih.gov.glaucoma.
A Confident Choice
ACUVUE® ADVANCE™ Brand Contact Lenses for ASTIGMATISM are the # 1 astigmatic lenses for new wearers. Eye Care Professionals surveyed said the comfort level of ACUVUE® ADVANCE™ Brand for
ASTIGMATISM was superior to other lens designs, and they also gave it high marks for its average settle time of 53 seconds. In a survey of more than 200 ECPs participating in a market test, 99% rated the lens very
good to excellent for ease of fit; and 98% agreed the rotational stability and predictable orientation of ACUVUE® ADVANCE™ for ASTIGMATISM was very good to excellent. With the increased comfort, ease of fit
and the highest UV protection available, ACUVUE® ADVANCE™ for ASTIGMATISM is designed to quickly give you complete confidence in your first choice lens. And now, ACUVUE® ADVANCE™ for ASTIGMATISM
meets more patients' needs with the introduction of -2.25 cylinder.
--ADVERTISING
Abstract:
MPDS Vs. Serratia Marcescens
Researchers at the University of New South Wales in Sydney recently compared the susceptibilities of clinical isolates of Serratia marcescens and the standard ISO ATCC 13880 strain
against five contact lens multipurpose disinfection solutions (MPDS). They tested five commercially available MPDS, containing either polyquaternium or polymeric biguanide using ISO/CD 14729 stand-alone test for
contact lens products against four ocular isolates of S. marescens and the strain ATCC 13880. Investigators measured the average log reduction in bacterial numbers at the manufacturer’s recommended disinfection
time and compared this with the criteria for stand-alone disinfection products for each MPDS against each bacterial strain.
All the MPDS tested met stand-alone criteria of 3-log reduction of
viable bacteria against the ATCC strain. However, they found more variability in the MPDS’ ability to meet disinfection criteria when testing against the clinical isolates. Two clinical isolates were found to be
significantly more resistant to disinfection than was the recommended ISO strain. Two polyquaternium-1-based solutions were less effective overall than the other MPDS against S. marscens.
The authors conclude that the results indicate the importance of strain selection for the testing of MPDS and say the use of a single laboratory strain may be insufficient to provide assurance that the disinfection
solution will be effective against clinical isolates. They also note that clinical isolates of S. marscens may show increased resistance to disinfection with polyquaternium.
Hume EB, Zhu H, Cole N, Huynh C, Lam S, Willcox MD. Efficacy of contact lens multipurpose solutions against serratia marcescens. Optom Vis Sci. 2007 Apr;84(4):316-20.
Editor's Commentary:
Irregular Cornea: Whatever Works
A few years ago, I conducted a survey among practitioners who I knew fitted contact lenses on a lot of irregular corneas. The most common comment: Do "whatever works." We all know that
the keratometer doesn’t tell a very complete story about corneal topography by a long shot. We had a penetrating keratoplasty (PK) case last week that failed with many lens types. The topography illustrated about
6.00D of toricity, which was decentered nasally, and a tight suture at 9 o'clock. I usually don't try bitorics on PK eyes, and even though this patient’s against-the-rule toricity wasn't perfectly centered, I thought
we'd try what we had not tried. We put on a diagnostic SPE bitoric lens with only 2.00D of toricity. A +6.00D sphere over-refraction provided the patient with 20/20 visual acuity over this plano/-2.00D lens. I am
always happy when I can use the SPE trial set. We have many articles on fitting these cases on the Contact Lens Spectrum Web site archives. Feel free to check it out at http://www.clspectrum.com.