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Issue: August 2003

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When Cornea Transplants Fail. What Next?
Keratoprosthesis Helps Patients Who Reject Donor Corneas.

Cornea transplants are highly successful in many patients, including those with diagnoses of keratoconus, corneal scars or endothelial dystrophy, all of which carry a good prognosis. And newer medications are helping to reduce the incidence of graft rejection. But what about the small percentage of patients who, because of immunologic response or other reasons, continue to reject their transplanted corneas?

The Dohlman Type 1

The Dohlman Type 1
post-op

There's hope for these individuals in the form of a procedure called keratoprosthesis surgery, which combines man-made materials and a human cornea to restore vision. In some of the best outcomes, keratoprosthesis has been able to give patients 20/40 vision.

Michael W. Belin, M.D., professor of ophthalmology at Albany Medical Center in Albany. N.Y., and in private practice with Cornea Consultants of Albany, recently performed his first keratoprosthesis procedure on a 71-year-old woman who had previously rejected several donor corneas. The woman had multiple vision-related problems, including diabetes and retinal detachments, that had left her permanently blind in one eye and capable of only discerning light in the other.

"I've been following the development of keratoprosthesis for some time," says Dr. Belin, who performs a large number of cornea transplants in his practice, "but it's only been recently that keratoprosthesis could offer a viable alternative for patients who've rejected natural corneas."

Dr. Belin used a Dohlman Type 1 rigid two-part, PMMA lens in the procedure he performed. This keratoprosthesis, developed by Claus Dohlman, M.D., at the Massachusetts Eye and Ear Infirmary in Boston, has been used in about 300 patients in the last decade, improving vision for about half of those individuals. In the 1-hour procedure, the Dohlman lens is first attached to a "carrier" donor transplant. The center of the natural cornea is then removed, and the keratoprosthesis along with the carrier donor cornea are sutured into place.

The AlphaCor lens, developed in Perth, Australia, is another type of keratoprosthesis. In a more time-consuming procedure, the AlphaCor is inserted in the lamellar bed of a patient's natural cornea. The cornea is then covered by a conjunctival flap for about 3 months. At the end of that period, the anterior central 3 mm is excised, exposing the underlying prosthesis.

"The Dohlman procedure provides an easier rehabilitation for the patient," says Dr. Belin. "The AlphaCor many be better for patients who have a lack of corneal sensation. They may benefit from having the flap. We're still learning about which procedure may be more suitable for which patients."

As for the woman who received the Dohlman keratoprosthesis from Dr. Belin, he reports that she's still in the healing process, but that her ability to see light has returned to preoperative levels.

Drug Giants Partner on New AMD Drug
Novartis Will Help Develop Genentech's Lucentis.

Novartis Ophthalmics, which is already a co-partner for Visudyne, the only drug therapy currently approved for the treatment of the wet form of AMD, has joined with Genentech to develop and commercialize another highly promising AMD treatment. The new drug, formerly known as rhuFab V2, will now be called Lucentis.

The agreement gives Novartis Ophthalmics an exclusive license to develop and market Lucentis outside of North America. Genentech will retain the marketing rights for Lucentis in North America.

Lucentis is one of the emerging class of anti-VEGF (vascular endothelial growth factor) drugs that cut off the formation of new blood vessels. In clinical trials, anti-VEGF drugs have shown effectiveness in stopping the growth of solid tumors, and also as a treatment for wet AMD. Lucentis is currently in Phase III clinical trials in the United States following a highly successful Phase Ib/II trial in which patients with various forms of wet AMD, on average, gained 9.0 letters on an ETDRS chart after 98 days. Patients in the study who were treated with the standard of care lost an average of 4.9 letters after 98 days.

While some saw the Novartis/ Genentech partnership as evidence that Visudyne would soon be surpassed by better therapies, Novartis Ophthalmics said its goal is to "strengthen our portfolio" of drugs to treat back-of-the-eye diseases. Paul Hastings, CEO of Visudyne co-developer QLT Inc., told Ophthalmology Management that the Novartis/Genentech partnership could be good news for QLT.

"We have a very upfront, direct and communicative relationship with Novartis Ophthalmics," said Hastings. "We are supportive of Novartis' association with Genentech. Genentech's expertise in anti-VEGF makes them a wonderful partner."

Hastings said combining Visudyne and an anti-VEGF drug such as Lucentis makes sense. A Phase I/II clinical trial using just that combination is currently under way.

"This combination makes sense because the anti-VEGF drug is designed to stop the formation of new blood vessels and Visudyne therapy acts to stop current leakage by sealing those vessels," said Hastings. "If you look at the way diseases are treated these days, there's more emphasis on finding combinations that are more effective than a single agent."

FDA Approves Light-Filtering IOL
Alcon's AcrySof Natural Filters Out UV and Blue Light.

The FDA has approved Alcon's AcrySof Natural Single-Piece IOL, which will become the newest addition to the company's AcrySof line of acrylic intraocular lenses. The AcrySof Natural is the first foldable ultraviolet (UV) and blue light-filtering IOL to reach the U.S. market and is specially designed to approximate the light-filtration properties of a healthy human lens.

The Acrysof Natural from Alcon

The Alcon lens incorporates a proprietary blue light-absorbing chromophore in addition to a UV light-absorbing chromophore to safely filter out ultraviolet and some high energy blue light.

"A growing body of evidence shows that high frequency blue light may cause retinal damage," says Robert Cionni, M.D., medical director of the Cincinnati Eye Institute. "The AcrySof Natural IOL filters out this potentially dangerous light without negative visual consequences."

The AcrySof Natural earned the CE Mark last year and has been well-received internationally.

"We believe many ophthalmic surgeons in the United States will also adopt this innovative technology for their patients," says Cary Rayment, senior vice president, Alcon U.S.

Alcon won FDA approval for the AcrySof Natural IOL after conducting a 297-patient clinical trial to prove the safety and effectiveness of the lens. 

Correction

The listing for the Carl Zeiss Meditec Stratus OCT was missing from the Retinal Scanners section of the Diagnostic Instrument Buying Guide, which was distributed with the July issue of Ophthalmology Management. Here is the listing as it should've appeared.

Company: Carl Zeiss Meditec

Model: Stratus OCT

Price/Fee: $59,950

Warranty: 1 year

Type of Laser: Super-luminescent Diode 820nm

Field of View: 26 vertical x 20.5 horizontal

Area of Retina Analyzed: RNFL, retinal layers, posterior pole, peripapillary and optic nerve head

Printout Detail: Objective measurements of retinal and RNFL thickness; retinal volume; normative data comparison for RNFL thickness; macular thickness; optic nerve head printout with disk, cup and rim measurements and ratios

Additional Features: Gives direct cross-sectional images of retinal layers with axial resolution of < 10m and transverse resolution of 20m. Anatomical representation of retinal layer defects. Objectively measures retinal thickness and volume and RNFL thickness. Includes an RNFL thickness normative database acquired using an FDA-approved protocol.

IN THE NEWS

Diabetes screening technology. The Doheny Retina Institute, part of the Keck School of Medicine at the University of Southern California, recently implemented ComMedica's O-PACS software technology for the early detection of Type II diabetes and other retinal complications.

The Web-based technology, which Doheny helped to develop, allows the Institute's doctors to view, share and make diagnostic decisions from fundus images sent from anywhere in the United States.

Conference Seeks to Make Driving Safer
One Priority: Vision Problems of Older Drivers.

How dangerous are drivers who need cataract surgery, but refuse to have it? Should individuals who require low-vision aids be allowed to drive?

It's legal to drive wearing a bioptic telescope in 34 states.

These were two of the issues tackled recently at the second "The Eye and the Auto" conference, sponsored by the Detroit Institute of Ophthalmology. The international symposium brought together researchers, design engineers, ophthalmologists, optometrists and representatives of the automotive industry to present ideas for improving driving performance and making vehicles easier and safer to operate.

With the number of drivers over the age of 70 expected to almost triple to about 38 million by 2020, several of the papers delivered at the conference focused on the vision problems of individuals who continue to drive into their senior years.

One study, conducted by a team of researchers led by Cynthia Owsley, Ph.D., professor of ophthalmology at the School of Medicine, University of Alabama at Birmingham, compared the accident rates of 103 drivers who required cataract surgery but declined to have it performed, against the accident rates of 174 drivers who had their cataracts removed.

In the follow-up period, the drivers who declined surgery had almost double the rate of vehicle accidents as the drivers who had their cataracts removed.

The researchers said ophthalmologists should use this information to emphasize the importance of cataract surgery to patients who want a lifestyle that heavily depends on driving.

Another study, presented by Eli Peli, O.D., of the Schepens Eye Institute of the Harvard Medical School, found that the rules for allowing visually impaired individuals to drive vary greatly from state to state. For example, bioptic telescopes are permitted for driving in 34 states despite the fact that some vision researchers have found that the ring scotoma caused by the magnification limits the driver's field of view.

Dr. Peli said new aids that provide visually impaired drivers with both a wide field of view and high resolution are needed. He said an in-the-lens bioptic telescope that his team has designed could provide the solution that would keep low-vision drivers on the road safely.

Infants Need Early Cataract Exams
38% Are Diagnosed Too Late.

Thirty-eight percent of otherwise healthy infants with infantile cataracts, a birth defect that requires surgery before the age of 6 weeks, aren't diagnosed with the condition early enough, a new study has found.

The study results, reported in the Archives of Pediatrics and Adolescent Medicine, also indicate that low-birth-weight infants are six times more likely to have infantile cataracts than babies whose birth-weight falls within the normal range.

As you know, infantile cataracts can cause blindness if untreated, and surgery by 6 weeks of age is recommended to preserve eyesight. Without visual input, sight-related areas of the developing brain may be irreversibly damaged.

The study findings emphasize the importance of newborn eye exams to detect any eye abnormalities, including cataracts, the authors say. A study conducted several years ago found that 14% of youngsters in a school for the blind had lost their vision due to infantile cataracts.

In the current study, Tricia R. Bhatti, M.D., of the Medical College of Georgia School of Medicine, led a team of researchers who evaluated medical records from a long-term birth defects surveillance program called the Metropolitan Atlanta Congenital Defects Program.

The researchers identified 199 infants born with cataracts between 1968 and 1998 -- a rate of two cases per every 10,000 births.

Of the cases that occurred as an isolated defect, 38% were diagnosed after 6 weeks, the researchers reported. And 15% of otherwise healthy infants weren't diagnosed until after they reached the age of 5 months.

REFRACTIVE SURGERY UPDATE

Expedited review for ICL. The FDA has accepted the Pre-Market Approval Application (PMA) for STAAR Surgical's Implantable Contact Lens (ICL) for expedited review. The FDA generally grants expedited review when a device offers the potential for clinically meaningful benefit as compared to the existing alternatives, or when the device promises to provide a revolutionary advance over currently available modalities.

The ICL, a phakic IOL, has been submitted to the FDA as a treatment for the correction of myopia in the range of -3D to -20D. STAAR is currently enrolling candidates in clinical trials for both the hyperopic ICL and the Toric ICL.

"This acceptance brings us one step closer to commercialization of the ICL in the United States," said David Bailey, president and CEO of STAAR Surgical. "We continue to believe we will be the first to market this technology in the United States. We have always asserted that the ICL would represent the next paradigm shift in refractive surgery and consider the granting of expedited review status by the FDA an underscore of this belief."

Epi-LASIK device. CIBA Vision has submitted a pre-market notification to the FDA for an epikeratome device to be used in a new refractive surgical procedure called Epi-LASIK. The device, called the EpiEdge, is a sub-epithelial separator that produces an epithelial sheet, thereby eliminating the need for alcohol in refractive laser procedures such as PRK and LASEK. Because alcohol is toxic to epithelial cells, CIBA Vision says using the EpiEdge in Epi-LASIK results in faster healing and less pain for patients. CIBA Vision anticipates launching the EpiEdge epikeratome in the United States later this year, pending FDA approval.

Epi-LASIK was developed by Ioannis Pallikaris, M.D., a Greek ophthalmologist who also was instrumental in the introduction of LASIK.

Refractec receives funding. Refractec Inc., developer of the Conductive Keratoplasty (CK) treatment for hyperopia, has received an additional $9 million in venture capital financing to expand the CK procedure throughout the United States. Since CK was approved last year, more than 16,000 of the nonlaser vision correction procedures have been performed. The minimally invasive CK procedure uses radiofrequency energy to reshape the cornea.

 


    

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