Plans for our 2007 Annual Regional Meeting in Beijing, China are shaping up nicely thanks to Program Directors Ronald R. Krueger, MD, and Jialiang Zhao, Sr., MD. You can find more details below. Our meeting will be held in partnership with the Chinese Ophthalmological Society and the Asia-Pacific Association of Cataract and Refractive Surgeons and in conjunction with the 9th Conference of the Chinese Cataract Society and the 2007 Chinese Refractive Society Conference. One new feature of this year's meeting is Academy Live, a special edition of the American Academy of Ophthalmology's popular weekly electronic newsletter, Academy Express. Two issues of Academy Live will be produced in Beijing to highlight the top clinical headlines from our meeting. We hope you enjoy it. – Marguerite McDonald, MD, FACS
- Wavefront not just for lasers anymore
- LASIK dry eye syndrome may be a form of corneal neuropathy
- Latest femtosecond laser creates smoother stromal surfaces than the latest mechanical microkeratome
- Gatifloxacin vs. moxifloxacin: a difference in healing, but not in visual outcome
- Ultrasound biomicroscopy shows promise for determining ICL length in phakic IOL implantation
- Women and higher myopes at increased risk for dry eye after LASIK
- Endothelial cell loss appears greater with small-incision DLEK compared to large-incision surgery
- Aspheric IOLs appear to provide better contrast sensitivity than conventional IOLs
- Pre-registration for the 2007 ISRS/AAO Regional Meeting in Beijing, China has closed
- Make your travel and hotel arrangements to Beijing today
- 2006 ISRS/AAO membership dues are payable now
-U.S. FDA approves new treatment options for the Allegretto Wave Eye-Q system
-AMO completes IntraLase acquisition
-U.S. regulatory agency grants “new technology” status for two Bausch & Lomb aspherical IOLs
-U.S. Navy to provide wavefront guided LASIK to 70,000 service members this year; pilots soon to be eligible for surgery
-Video games may be an effective training tool for surgeons
- Upcoming meetings
LASIK dry eye syndrome may be a form of corneal neuropathy
Even though objective clinical signs of tear insufficiency and hypoesthesia were negative, 55 percent of patients who had LASIK for high myopia reported ongoing dry eye symptoms. Researchers conclude that dry eye symptoms may represent a form of corneal neuropathy rather than dry eye syndrome. Journal of Refractive Surgery, April 2007
Latest femtosecond laser creates smoother stromal surfaces than the latest mechanical microkeratome
A comparison between flaps created with a Zyoptix XP microkeratome (using a fresh blade for each donor eye) and the 60 kHz IntraLase femtosecond laser finds a statistically significant difference in bed smoothness as measured by qualitative roughness and quantitative roughness scores. Journal of Refractive Surgery, April 2007
Gatifloxacin vs. moxifloxacin: a difference in healing, but not in visual outcome
This prospective, randomized trial finds that despite a difference in epithelial healing between the two antibiotics, visual outcomes were similar in terms of UCVA, BSCVA, MSE and corneal haze at six months after photorefractive keratectomy., April 2007
Ultrasound biomicroscopy shows promise for determining ICL length in phakic IOL implantation
A retrospective analysis finds this alternative method for sulcus-to-sulcus horizontal diameter estimation achieved more desirable ICL vault than the conventional method at one and six months postop. All 13 eyes showed ideal vault in the ultrasound group, compared to 58.8 percent in the conventional method group. Journal of Refractive Surgery , April 2007
Women and higher myopes at increased risk for dry eye after LASIK
This retrospective study of 190 eyes finds 20 percent of eyes experienced chronic dry eye persisting six months or more after surgery. The risk was significantly associated with higher attempted refractive correction, greater ablation depth and female sex. European Journal of Ophthalmology , March 2007
Endothelial cell loss appears greater with small-incision DLEK compared to large-incision surgery This prospective, non-comparative study of 88 patients (100 eyes) finds initial cell loss was minimal with both techniques. But at one and two years postop, cell loss with small-incision DLEK, which involves folding of the donor tissue, was significantly higher than that found after large-incision surgery (27 percent vs. 43 percent). Ophthalmology, March 2007
Aspheric IOLs appear to provide better contrast sensitivity than conventional IOLs This prospective, randomized study finds contrast sensitivity in eyes with the AcrySof IQ SN60WF IOL was significantly higher at all spatial frequencies under mesopic conditions (with and without simulated glare), compared to the AcrySof Natural SN60AT or AcrySof SA60AT IOLs. Under photopic conditions, mean contrast sensitivity with the aspheric IOL was higher only at 18 cycles per degree. Journal of Cataract and Refractive Surgery, April 2007
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Pre-registration for the 2007 ISRS/AAO Regional Meeting in Beijing, China has closed
Onsite registration begins May 25. Program Directors Ronald R. Krueger, MD, and Jialiang Zhao, Sr., MD, have brought together refractive and cataract surgery leaders from around the globe to share the latest developments in the field. The meeting, Expanding Horizons in Refractive and Cataract Surgery, is scheduled for May 25-27.
Make your travel and hotel arrangements to Beijing today
ISRS/AAO has posted resources on its Web site to help you plan a successful trip to Beijing, from travel and housing information to a letter of invitation and program schedule.
2006 ISRS/AAO membership dues are payable now
If you have already paid your dues, thank you. If not, you can do so online.
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U.S. FDA approves new treatment options for the Allegretto Wave Eye-Q system
WaveLight’s second Allegretto Wave system introduced in the U.S., the Eye-Q system, has been approved for wavefront-guided and mixed astigmatism indications.
AMO completes IntraLase acquisition
WaveLight’s second All As expected, IntraLase stockholders approved the purchase on March 30. AMO, which acquired WaveFront Sciences (developer of the COAS Precision Aberrometer) in January, said it plans to further establish its position as "the industry leader in laser diagnostics, flap-creation and ablation technologies."
U.S. regulatory agency grants “new technology” status for two Bausch & Lomb aspherical IOLs
The New Technology Intraocular Lens (NTIOL) designation for the SofPort Advanced Optics and SofPort Advanced Optics with Violet Shield became effective March 6 and will remain in effect until Feb. 26, 2011. The designation means the lenses are now eligible for an additional $50 payment when provided to a Medicare beneficiary in an ambulatory surgical center.
U.S. Navy to provide wavefront guided LASIK to 70,000 service members this year; pilots soon to be eligible for surgery
The Navy said it has funding to provide wavefront guided LASIK with IntraLase to 70,000 sailors and Marines by October. Pilots and aviation candidates are expected to be approved for surgery this fall. Short and long-term effects on pilot health and performance will be evaluated.
Video games may be an effective training tool for surgeons
A study in the February issue of Archives of Surgery finds surgeons who play video games made 37 percent fewer errors in a simulated surgery skills course, were 27 percent faster and scored 42 percent better overall than surgeons who never played video games.
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|UPCOMING MEETINGS |
|May 26-27, 2007 |
2007 ISRS/AAO Meeting:
Expanding Horizons in Refractive and Cataract Surgery
|June 9-12, 2007|
Joint Congress of SOE/AAO 2007
|May 31 - June 3, 2007 |
XXVII Pan-American Association of Ophthalmology
|November 9 -10, 2007|
American Academy of Ophthalmology's Refractive Surgery Subspecialty Day
New Orleans, Lousiana
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Wavefront Isn’t Just For Lasers Anymore
Marguerite B. McDonald, MD, FACS, and Perry S. Binder, MS, MD
Two new types of spectacle lenses that incorporate wavefront technology are worth considering for post-surgical fixes, surgery-averse presbyopes and others
It’s a little unusual for refractive surgeons to be singing the praises of spectacles. After all, we spend most of our time and energy trying to help patients get out of their glasses. But a new generation of spectacle lenses deserves consideration from anyone interested in the intersection of wavefront science and visual performance.
Interestingly, these developments follow the same trends we’ve seen in refractive surgery. The ability to measure and analyze vision through wavefront aberrometry made it clear that conventional laser surgery actually induces unwanted aberrations. Conventional progressive spectacles do the same thing. Essilor (Dallas, Texas) recently introduced a new progressive spectacle lens that uses wavefront technology to minimize these aberrations.
As refractive surgeons, we’ve also learned that good vision isn’t good enough. Because of higher-order aberrations (HOA), it is possible for a person with 20/20 vision to still have quality-of-vision problems. Ophthonix (San Diego, Calif.) recently introduced custom spectacle lenses that attempt to correct both lower- and higher-order aberrations for patients’ individual wavefront map.
For the comprehensive ophthalmologist, it’s important to know about these new technologies so we can steer our spectacle-wearing patients toward options that offer the best opportunity to maximize their visual potential. There are also interesting applications for post-surgical patients and others with quality-of-vision problems.
Essilor Varilux Physio Lenses
Progressive lenses have been a great improvement over line bifocals or trifocals, offering a range of vision and cosmetic appeal. However, they have very complex refracting surfaces, with power variations across the lens that cause distortions that can interfere with good quality vision.
Essilor used wavefront technology to conduct a point-by-point analysis of the combined front and rear surfaces of its progressive lens to identify the lower- and higher-order aberrations caused by the progressive design. The Varilux Physio lenses are not customized to patients’ actual wavefront error, instead, wavefront data are used to minimize or neutralize distortions in the lens itself.
The result was an improvement in all three fields of the lens when compared to Varilux Panamic, the gold standard in conventional progressive design:
- Distance – 300 percent reduction in HOA, especially coma. HOAs were measured by averaging data taken from five locations on each lens. The reduction in HOA should provide Physio wearers with sharper focus, especially toward the periphery of the lens.
- Intermediate – 30 percent wider intermediate field. The amplitude of residual astigmatism has been reduced. In addition, the wavefront-optimized lens has a more consistent vertical orientation of the axis of astigmatism, which makes it easier for the eye to ignore it.
- Near– 10 percent reduction in maximum defocus. The Physio lens has improved power control along a greater vertical area. This should improve patients’ ability to perform prolonged near tasks by making reading vision more consistently crisp and comfortable.
These comparisons were all made using lenses with a refractive index of 1.67 and a prescription of plano with a +2.00-D add. But they hold true when the Physio lenses are compared to other progressive lenses in a typical patient population.
In a large European study, spectacles with Varilux Physio lenses were dispensed to 609 randomly selected presbyopes. Their corrections ranged from -10.00 to +6.00 D, up to 4.00 D of cylinder, with add powers ranging from 0.75 to 3.50 D.
After wearing their new glasses for three weeks, the majority of patients reported “wider” or “clearly wider” fields of near, intermediate and distance vision compared to that with the progressive lenses they wore previously. Almost three out of four said their overall quality of vision was “better” or “clearly better.” They experienced the greatest gains in near vision.
The Varilux Physio lens represents a major advance in progressive spectacle lenses. Patients who are already wearing progressive spectacles will appreciate the differences. But more importantly, these lenses have much to offer those who are unsatisfied with progressive lenses, and to those who have yet to try them.
Ophthonix iZon Lens
The iZon lenses are actually customized to the patient’s wavefront map, with the goal of improving visual acuity and quality of vision.
The process starts with a wavefront prescription generated by the Z-View aberrometer. This is a unique aberrometer that relies on proprietary holographic grating technology. When tested on model eyes against manifest refraction and established Hartmann-Shack aberrometers, the Z-View gave accurate and reproducible measurements. (In Press J Cat Refr Surg)
It offers the potential for an objective refraction, just like we rely on for customized laser refractive surgery.
Each lens is customized to the patient’s lower and higher-order (through the 6th Zernike order) refractive error. Zernike terms that are at or near zero are excluded. The system also automatically identifies whether the patient is a good candidate for an iZon lens (about 65 percent are good candidates) and provides a simulation of the patient’s expected vision.
The lenses, which currently must be made by an Ophthonix lab, are made of a proprietary polymer that can be programmed with the digital wavefront information, much like burning a CD.
They have a refractive index of 1.6. They come with anti-reflective, UV-blocking, scratch resistant and hydrophobic coatings, and can fit in a wide range of contemporary frames. The iZon lens is similar in weight and thickness to other high-index spectacle lenses and is available in single vision or progressive lenses.
In clinical trials, the company found statistically better visual acuity, low-contrast visual acuity, and mid-frequency contrast sensitivity with iZon compared to conventional lenses. Patient satisfaction ratings were high.
In a recent randomized, double-masked study, 44 subjects underwent reaction testing on a simulated night driving course wearing the iZon lenses and conventional lenses with the same refractive index and anti-reflective coatings.
The iZon lenses produced a statistically significant improvement in reaction time for 10 of 12 hazard conditions, such as pedestrian street crossing. The average improvement was about 0.25 seconds, which is greater than 20 feet when driving at 55 mph.
A small study of 10 patients with age-related macular degeneration demonstrated that the wavefront-customized lenses improved visual performance, especially in glare conditions. They have also found these spectacles to be very helpful in post-refractive surgery cases. The vast majority of refractive surgery patients have excellent outcomes, but there is a small subset with no clinical improvement in their quality of vision with these spectacles. Some of these patients had previous LASIK enhancements or were ineligible for an enhancement, and many were unable to wear contact lenses. Although more studies are needed, this is a very promising technology for people who have nowhere else to turn.
The wave of the future?
Ophthalmologists are uniquely positioned to understand the benefits of wavefront. We should be at the leading edge of wavefront technology, even as it relates to spectacles and contact lenses. We recommend:
- For patients who choose to wear glasses, prescribe the best options available;
- Encourage presbyopes who are wearing line bifocals to migrate to newer technology;
- Try wavefront-corrected lenses for post-surgical problem cases.
Some might consider the incorporation of wavefront technology into corrective eyewear as a threat to refractive surgery. In our opinion, patients who want to be free of spectacles and contact lenses will be motivated to seek surgical solutions no matter how good their eyewear is.
Moreover, the expansion of wavefront technology – and the increased knowledge and data that will inevitably result – is a positive development for the entire eye care field . The future of refraction and refractive correction demands that we all
adopt new standards for fully optimized, customized vision.
Dr. McDonald is in private practice with Ophthalmic Consultants of Long Island in Lynbrook, N.Y. Contact her at (516) 593-7778 or email@example.com.
Dr. Binder is in private practice at Gordon Binder & Weiss Vision Institute in San Diego, Calif. He is a consultant for Ophthonix. Contact him at +1-858-455-6800 or firstname.lastname@example.org.
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