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News
Embryonic Stem Cells and Vision Research
On March 9, 2009, President Barack Obama signed an executive order lifting restrictions on the use of federal funding for research on human embryonic stem cells. President George W. Bush had limited federal money for human embryonic stem cell research to 21 preexisting stem cell lines derived prior to August 9, 2001. Under President Obama's order, federal funding may not be used for human cloning, but it may be used to study existing cell lines. Additionally, Mr. Obama signed a presidential memorandum directing the head of the White House Office of Science and Technology Policy to develop a strategy to ensure that scientific integrity guides the government's decision making.
Medical organizations such as the AMA and the Association for Research in Vision and Ophthalmology (ARVO) support the President's decision to fund stem cell research. In a statement issued by the organization, the AMA's board chair, Joseph Heyman, MD, said that the policy would lead to life-saving benefits. "Stem cell research holds great promise to treat diseases that science has so far been unable to cure, and this change in policy will allow researchers to accelerate their efforts by applying for federal research funds."
Bobbie Ann Austin, PhD, assistant director of the ARVO's Science Program and Policy, issued a statement saying that the organization "will follow the development of new guidelines and amend the current stem cell policy to include ethical use of newly created stem cell lines in vision research."
What will President Obama's order mean for vision research, specifically for cataract and refractive/corneal surgery? Tal Raviv, MD, a cornea specialist, told Cataract & Refractive Surgery Today that the executive order will allow many more federally funded laboratories to investigate ocular therapies. "I welcome advancements in difficult-to-treat conditions such as bilateral corneal stem cell failure, endothelial disease, or multirejection cornea transplantation," he said. "Ultimately, engineering an in vitro cornea may be possible as a result of research on embryonic stem cells. Stem cell research may also expand our understanding of how to treat retinal, macular, and optic nerve disease. Nevertheless, embryonic research has ethical and moral responsibilities, and I support prudent regulation and oversight to ensure these are met." Dr. Raviv is an assistant professor of ophthalmology at New York Medical College in Valhalla, an attending cornea and refractive surgeon at the New York Eye and Ear Infirmary, and a founding partner of New York Laser Eye.
William B. Trattler, MD, has been following the research of Pete Coffey, PhD, of the University College London Institute of Ophthalmology, on stem cell surgery for age-related macular degeneration. "Dr. Coffey and his team have grown retinal pigment epithelial cells from embryonic stems cells in animals.," Dr. Trattler told CRSToday.
Dr. Coffey hopes that a curative therapy will be available by 2011 for British citizens with this blinding disease. "President Obama's order to lift restrictions on funding for human embryonic stem cell research allows for the possibility that treatment discoveries like Dr. Coffey's can happen in the United States. Having the ability to conduct this line of research provides future generations with additional treatment options for diseases of the eye, like age-related macular degeneration." Dr. Trattler is a cornea specialist at the Center for Excellence in Eye Care in Miami and a volunteer assistant professor of ophthalmology at the Bascom Palmer Eye Institute in Miami.
Although embryonic stem cell research could bring about advances in vision research and therapies for diseases like diabetes, Parkinson's, and Alzheimer's, opponents argue that the policy is unethical because it condones the destruction of innocent human life. Some in favor of the policy, like Mark Packer, MD, refute the notion that human life is endangered by Obama's decision. Dr. Packer is a clinical associate professor of ophthalmology at the Casey Eye Institute, Oregon Health & Science University, and he is in private practice at Drs. Fine, Hoffman, & Packer in Eugene, Oregon. "I believe this research is ethical because I do not ascribe consciousness to undifferentiated embryonic cells," he told CRSToday. "Nevertheless, prudent oversight is needed to ensure that researchers uphold the updated regulations and guidelines to be put forth by the National Institutes of Health. I support Mr. Obama's decision, and I believe that all human research carries significant ethical and moral responsibilities."
Femtosecond Laser Introduced at Dulaney-AIRS Meeting
Stephen G. Slade, MD, delivered a presentation at the March 2009 Dulaney Aspen Invitational Refractive Symposium on the femtosecond laser for refractive cataract surgery being developed by LenSx Lasers Inc. (Aliso Viejo, CA). The LenSx laser is designed to liquefy, soften, or chop the nucleus; perform a perfectly sized and centered capsulotomy; and create all corneal incisions.
In his presentation, Dr. Slade, medical director of LenSx Lasers, presented results from two clinical studies. The initial clinical studies, conducted by Zoltan Nagy, MD, associate professor at Semmelweis University in Budapest, Hungary, included more than 125 eyes. All laser capsulotomies were well centered, and 100% were within 0.2 mm of the intended diameter. The laser capsulotomies were removed with no radial tears or adverse events. A second study evaluated the use of the LenSx laser for liquifying the lens (ie, softer cataracts) and fragmentating the lens (ie, harder cataracts). In 26 patients with softer lenses, the nucleus was effectively liquefied and removed with the I/A tip only. Twenty-one patients with hard lenses were treated with laser lens fragmentation, which reduced the need for sculpting by prechopping the nucleus.
"Any way to safely and precisely perform all the incisions, capsulotomy, and handle the nucleus would be important to the future of refractive cataract surgery," Dr. Slade commented. "Currently, only about 5% of all cataract patients are in the premium channel either due to patients' declining or not being offered the technology. I believe that femtosecond laser-assisted refractive cataract surgery could be a key to increasing adoption of the premium cataract channel."
Dr. Slade is one of five coauthors of a paper to be presented about LenSx's laser at the 2009 annual meeting of the American Society of Cataract and Refractive Surgery in San Francisco.
Alcon Receives Aspheric Toric IOL Approval, Signs LCA Vision Deal
The FDA approved the AcrySof IQ Toric IOL (Alcon, Inc., Huenenberg, Switzerland). According to a company news release, the acrylic single-piece lens offers an enhanced aspheric optic that improves image quality and increases contrast sensitivity in cataract surgery patients with astigmatism. Alcon will commercially launch the AcrySof IQ Toric IOL at the 2009 ASCRS annual meeting in San Francisco.
In other news, according to a 5-year contract between Alcon Laboratories, Inc. (Fort Worth, TX), and LCA Vision, Inc. (Cincinnati, OH), LCA will install Alcon's Allegretto Wave Eye-Q 400-Hz excimer lasers in LCA's 75 LasikPlus vision surgery centers by the end of the third quarter of this year. Alcon gained the US rights to the Allegretto laser when it acquired WaveLight AG in February 2008.
Durezol Under Review for Uveitis Indication
Sirion Therapeutics, Inc. (Tampa, FL), announced that its supplemental New Drug Application for Durezol (difluprednate ophthalmic emulsion) 0.05% for the treatment of endogenous anterior uveitis has been accepted for review. The FDA approved Durezol in June 2008 for the treatment of postoperative inflammation and pain associated with ocular surgery. The FDA has issued an action date of October 24, 2009, for the supplemental New Drug Application, according to a news release.
Enrollment Completed for Corneal Implant Study
Enrollment is complete for the phase 3 LUCIDA (Lux Corneal Transplant Implant Development and Advancement of Therapy) clinical trial for Lumitect (LX201; Lux Biosciences, Inc., Jersey City, NJ). According to a company news release, the LUCIDA trial is investigating the 1-year use of Lumitect in patients at elevated immune-mediated risk of rejection or graft loss subsequent to corneal transplantation. Lumitect is a silicone matrix ocular implant that steadily releases therapeutic doses of cyclosporine A into the eye for 1 year.
The trial includes 493 patients in three protocols. Participants in each protocol are randomized to receive implants containing two different dosages of active drug (cyclosporina A) or placebo. The 0.75-inch implant elutes approximately 20 to 25 µg/day, and the 0.5-inch elutes approximately 15 µg/day of the active drug. The endpoint for all three protocols is the incidence of rejection episodes or graft loss at 1 year for each dosing group versus placebo.
AMO Renamed Abbott Medical Optics Inc.
Abbott (Abbott Park, IL) completed its acquisition of Advanced Medical Optics, Inc. The latter is now a wholly owned subsidiary of Abbott and has been renamed Abbott Medical Optics Inc. (AMO).
In an interview with Cataract & Refractive Surgery Today, Jim Mazzo, president of AMO, reiterated that the company will remain an independent entity and continue to provide the full range of refractive, cataract, and corneal products for which it has been known. He also said that having the size, scope, and global influence of Abbott will allow AMO's strategy to expand. "We will have the financial support to accelerate the development of new technologies," Mr. Mazzo said. "We will continue to grow AMO through our organic pipeline as well as explore other technologies such as glaucoma implants and retinal devices."
Mr. Mazzo also stressed that the transition should be seamless for AMO's existing clients. AMO will continue to work with the same sales and marketing representatives and customer service team, he said.
Mr. Mazzo believes that the AMO of today will provide ophthalmologists with even greater technologies and resources. "If I was an ophthalmologist, I would be very excited about Abbott Medical Optics. Abbott, a very powerful and successful company, is entering the ophthalmic space for the first time," he said. "Businesses do not invest resources—people, time, and money— unless they know that there will be a positive return. There are many unknown frontiers in our space that we can explore with Abbott. This can only be a positive thing for our doctors."
Bausch & Lomb Signs Two Industry Agreements
Bausch & Lomb (Rochester, NY) and Pfizer Inc. (New York, NY) will copromote both companies' prescription ophthalmic drugs in the United States. Under the 5-year agreement, both companies' sales forces will promote Pfizer's Xalatan (latanoprost ophthalmic solution) and Bausch & Lomb's Alrex (loteprednol etabonate ophthalmic suspension 0.2%), Lotemax (loteprednol etabonate ophthalmic suspension 0.5%), Zylet (loteprednol etabonate 0.5% and tobramycin 0.3% ophthalmic suspension), and besifloxacin ophthalmic suspension 0.6%. The FDA is expected to approve the test drug this year. Pfizer will continue to maintain three midstage-development programs in its own pipeline, the news release said.
Additionally, Bausch & Lomb has obtained the rights to hydrophobic acrylic polymers made by Santen Pharmaceutical Co., Ltd. (Osaka, Japan), according to a news release. Under the terms of the agreement, Bausch & Lomb may commercialize new IOLs made from this material for sale worldwide. Santen reserves the right to use these materials in the Japanese market.
Surface Ablation Safe, Effective for Patients With Thin Corneas
Ten-year follow-up data suggest that surface ablation is safe and effective for correcting myopia in eyes with corneas thinner than 500 µm.1
Laura de Benito-Llopis, MD, of Vissum Madrid in Spain and colleagues conducted a retrospective study that included 75 eyes (49 patients). All patients had a preoperative central corneal thickness (CCT) of less than 500 µm, underwent surface ablation to correct their myopia, and were observed for at least 10 years.
At 3 months and 1, 2, 5, and 10 years after surgery, the investigators evaluated the stability of subjects' visual acuity and refraction, predictability, corneal keratometry, safety, efficacy, and postoperative complications.
Before surgery, the mean CCT was 481.54 ±15.7 µm (range, 438 to 499 µm), and the mean spherical equivalent was -6.12 ±2.67 D (range, -2.00 to -14.00 D). BSCVA improved significantly (P<.01) during follow-up, whereas UCVA showed significant improvement at year 1 and all subsequent visits, the researchers said.
Both the sphere and cylinder showed a slight but significant regression (P<.01) between 3 months and 10 years after surgery, according to investigators. Thirty eyes (40%) were within 0.50 D, and 43 eyes (57.33%) were within 1.00 D of emmetropia at the 10-year examination.
The safety index improved over the 10-year period and was always higher than 0.9. The efficacy index remained stable at around 0.8. Topography did not show signs of corneal ectasia, and keratometry readings showed no increase in corneal power. Thirty eyes (40%) needed an enhancement, the study's authors said.
Combined Glaucoma/Cataract Surgery Procedure Lowered IOP
The Ex-Press mini glaucoma shunt (Optonol Ltd., Neve Ilan, Israel) effectively lowered IOP when implanted under a scleral flap as a single procedure or combined with cataract surgery, according to a study in the Journal of Glaucoma.1
Elliott M. Kanner, MD, PhD, and colleagues at the University of Tennessee in Mephis compared the clinical outcomes of 231 eyes implanted with the Ex-Press and 114 eyes that underwent implantation combined with cataract surgery. Both groups were treated intraoperatively with mitomycin C.
Patients who received the device alone were observed for 25.7 ±11.1 months (range, 1 to 46.2 months). Those who received the combined treatment were observed for 21.9 ±12.5 months (range, 1.9 to 46.2 months).
Three years postoperatively, the researchers noted surgical success in 219 eyes (94.8%) implanted with the Ex-Press alone and 109 eyes (95.6%) treated with the combined procedure (P=.948). Success was defined as a postoperative IOP between 5 and 21 mm Hg, with or without medications and without further surgery. Compared with baseline values, the postoperative IOP and number of glaucoma medications had decreased significantly in both groups. The change from baseline IOP, however, was significantly greater after the Ex-Press' implantation alone versus in combination with cataract surgery (P<.001). The most common device-related complication was obstruction of the tube (six eyes), which was treated successfully with the Nd:YAG laser, the investigators said.
Cataract & Refractive Surgery Today asked Dr. Kanner for his perspective on the value of this study for cataract and refractive surgeons. "The Ex-Press implant significantly reduces postoperative complications, specifically hyptonony and complications that can follow from it," Dr. Kanner said. "There is also a very controlled anterior chamber during the surgery, and no iridectomy or sclerostomy, which reduces inflammation and intra- and postoperative bleeding."
Inhaled, Oral Corticosteroids May Increase Cataract Risk
The combined use of inhaled and oral corticosteroids increases patients' long-term risk of developing posterior subcapsular cataracts and nuclear cataracts, according to a report in Ophthalmology.1
Jie Jin Wang, MMed, PhD, at the University of Sydney and fellow researchers with the Blue Mountains Eye Study used questionnaires to assess 3,654 participants' use of inhaled and oral corticosteroids at baseline. Those who used these medications for at least 1 month in the past but were not using them at baseline were considered past users. Participants who were taking these medications at baseline and had been doing so for at least 1 month were considered current users.
The investigators examined all participants (aged 49 years or older) from 1992 through 1994 for nuclear, cortical, and posterior subcapsular cataracts. After 5 years, 2,335 participants were re-examined; after 10 years, 1,952 were re-examined.
At baseline, 103 participants were current users, and 120 were past users of inhaled corticosteroids, and 31 were current and 147 were past users of oral corticosteroids. Over the 10-year follow-up period, current users had a greater risk of developing posterior subcapsular and nuclear cataracts but not cortical cataracts, the researchers said. The interaction between inhaled and oral corticosteroid use was significant for the incidence of posterior subcapsular cataracts (P=.01) and nuclear cataracts (P=.02). In subgroup analyses, the investigators found that only individuals who used both inhaled and oral corticosteroids were at increased risk of developing posterior subcapsular cataracts.
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