Committee seeks understanding of keratectasia

WAILEA, U.S.A. — Many ophthalmologists are unclear regarding what is known and not known about post-LASIK keratectasia, and a committee is working to establish a better understanding of the condition through an evidence-based approach, according to a speaker here.

In a presentation at Hawaiian Eye 2006, Helen K. Wu, MD, described recent efforts by an ad hoc committee to address this. She and other prominent refractive surgeons are members of the committee, which is headed by Perry Binder, MD, and Richard L. Lindstrom, MD.

Helen K. Wu

The committee began its work, she said, after the now infamous case in which a New York jury awarded US$7.25 million — the largest award to date — to a LASIK patient who claims he suffered severe vision damage from the surgery.

“[Following that verdict] it became clear that there was an extreme difference in opinion regarding the extent of knowledge about keratectasia, specifically about what the established risk factors are and when they became the standard of care,” Dr. Wu said. She said she and her fellow committee members will seek to establish what is known about iatrogenic corneal ectasia – the incidence of which is unknown – and to create a registry of cases induced by LASIK or PRK, “in an attempt to provide an evidence-based approach.”

The group recently published a consensus opinion to summarize current knowledge about corneal ectasia. The paper was published simultaneously in the November/December issue of the Journal of Refractive Surgery and the November issue of the Journal of Cataract and Refractive Surgery.

More presentations from Hawaiian Eye 2006 are highlighted in the remainder of this article. Many of these items appeared first on OSNSuperSite.com as daily reports from the meeting.

Refractive Surgery

Adding phakic IOLs to practice can spur growth

With proper planning, phakic IOLs can be profitably and seamlessly added to any surgeon’s comprehensive refractive surgery practice, according to David Hardten, MD. He said phakic IOLs have been a “tremendous growth area” in his practice.

Dr. Hardten said the advantages of phakic IOLs include their ability to address higher refractive errors and their easily learned implantation techniques. He said phakic IOLs offer retention of accommodation, removability, excellent visual results and a low risk of complications.

While he acknowledged that phakic IOL implantation is a relatively low-volume procedure, Dr. Hardten said the highly myopic patients who are candidates for this refractive surgical option are “energetic ambassadors.”

“When they are happy, they are really happy. If you come to be known as someone who helps these highly disabled patients in your community, that is really good word of mouth,” he said.

To optimize efficiency when introducing phakic IOLs to a practice, the surgeon must plan training sessions for all technical and support staff, Dr. Hardten said. Documents such as consent forms and postoperative instructions should be prepared in advance, he said.

Surface ablation to enhance LASIK

Surface ablation techniques can be used to enhance the results of previous LASIK, particularly when the condition of the cornea complicates lifting the flap, according to William B. Trattler, MD.

Dr. Trattler said PRK or laser epithelial keratomileusis may be indicated as enhancement techniques for post-LASIK patients with certain corneal conditions. These conditions can include an insufficient residual stromal bed; consecutive hyperopia after primary myopic LASIK; intraoperative or postoperative flap problems; flaps that are difficult to lift because too much time has gone by since the LASIK procedure; and severe dry eye syndrome.

Dr. Trattler reported on a retrospective study of 89 eyes treated with either PRK or LASEK to enhance previous LASIK. He and colleagues found that “there was a strong trend toward improvement in [best corrected visual acuity]” following the surface ablation procedures, Dr. Trattler said.

Personalized nomogram improves custom ablation

Harry S. Brown, MD, was the 2006 recipient of the Hawaiian Eye Foundation International Award for Excellence. Image: Archer ME, OSN

Refractive surgeons can optimize their LASIK results and avoid systematic errors in their patients by adopting a personalized nomogram for custom ablation, according to Yunhee Lee, MD.

Dr. Lee explained that even two surgeons with nearly identical surgical styles, using the same laser in the same laser suite, will have slightly different outcomes when using the same nomogram.

Dr. Lee and colleagues used regression analysis to analyze the results of conventional vs. customized LASIK, as well as the results of customized LASIK performed by two surgeons using the same nomogram.

Graphed on a scatterplot, the outcomes of the two surgeons — both using the same customized laser platform, staff, laser suite and technical style — differed by approximately 0.75 D, she said.

“Indeed, the slopes of these scatterplots are not identical [as we expected], but to differ by about 0.75 D underscore the need for personalized nomograms,” Dr. Lee said.

Visian ICL effective in hyperopia

The STAAR Visian ICL is a good choice for refractive surgical correction in hyperopic patients, according to Paul Dougherty, MD.

Dr. Dougherty said the Visian ICL, which is implanted behind the iris in phakic eyes, is his lens of choice for patients who are under 50 years old with at least 3 D of hyperopia.

“These are some of the happiest patients in my practice,” said Dr. Dougherty, a clinical investigator for the lens who has 3 years of follow-up on some patients.

Addressing the concern that the posterior chamber lens may cause cataracts, Dr. Dougherty said this has not been a significant problem in his experience, but he did say he has seen a small number of lens opacities in his patients.

“These are patients who you would think of doing refractive lensectomy on anyway, so typically the worst thing that can happen is very treatable,” he said.

Cataract Surgery

Recognizing retinal complications

Cataract surgeons who learn to recognize signs of vitreous or retinal complications in their patients are “halfway home to solving the dilemma” for themselves, said Carmen A. Puliafito, MD, MBA.

Carmen A. Puliafito

Dr. Puliafito delivered the keynote lecture “Management and prevention of cataract surgery complications: A vitreoretinal surgeon’s perspective” at the meeting.

“The first thing is to recognize complications. Not all of them are obvious,” Dr. Puliafito said. “If something seems [strange] to you, stop and ask yourself if the globe has been perforated.”

He noted that while complications sometimes have to do with technique, they can occur “even in the best of hands.”

Endophthalmitis, which is thought by some to be on the rise due to the adoption of clear corneal incision techniques, is still relatively rare, Dr. Puliafito said. Other risk factors may be responsible for the increased incidence of this complication following clear corneal cataract surgery, he said, such as compromised immunity, preoperative blepharitis and use of a lidocaine gel before povidone-iodine application.

‘HyperCruise’ system reduces energy delivery

A phacoemulsification system that combines technologies from several companies can allow surgeons to raise their vacuum levels, reduce energy delivery, increase overall safety and improve efficiency, according to one surgeon.

Elizabeth A. Davis, MD, said the use of this “HyperCruise” system has provided better patient outcomes.

Dr. Davis explained that the HyperCruise system combines the Bausch & Lomb Millennium Microsurgical System with venturi pump; the STAAR Surgical CruiseControl device; the Chop X1 phaco tip from MicroSurgical Technologies; and a Bausch & Lomb #D4600 air exchange line.

She said any phaco tip can be used, and still the maximum vacuum setting can be set at 400 mm Hg. The system has broad applicability, she said, and is “married best with venturi,” but it can also be used with a peristaltic pump.

Dr. Davis said that the CruiseControl device “prevents surge by increasing resistance and decreasing interior diameter” of the phaco tube lumen, which she said is beneficial during cataract surgery.

Using the Bausch & Lomb power module, she said, energy is conserved and heat is reduced. She uses a setting of 55 pulses per second at a 58% duty cycle.

Glaucoma

Electronic tools may improve compliance

Electronic devices and tools may help patients with glaucoma be more adherent to their medication regimens, said Mildred M.G. Olivier, MD.

Dr. Olivier said that electronic eye drop medication monitors currently being developed “may be the most reliable tool to measure compliance in glaucoma patients.”

“One of the most common reasons for patients not to be compliant is that they just forget to take their drops,” Dr. Olivier said.

She described two devices: one for use with Lumigan (bimatoprost, Allergan) and another for use with Travatan (travoprost, Alcon).

Both devices sound an alarm after 23 hours to remind patients that they need to take their drops again, Dr. Olivier said.

Innovations may reduce invasive procedures

Recent innovations in glaucoma surgery may lead to a reduction in the number of invasive procedures needed by glaucoma patients, said Richard A. Lewis, MD.

He provided an overview of recent technological developments in glaucoma surgery, including Optonol’s ExPress miniature glaucoma shunt, selective laser trabeculoplasty, endoscopic cyclophotocoagulation and the AquaFlow drainage device from STAAR Surgical.

Dr. Lewis said these recently developed procedures have reduced the occurrence of some early and late postoperative problems. With each of these procedures there is no bleb, and therefore there are “no bleb-related complications, and no hypotony,” he said.

Cornea/external disease

Virologist: New antivirals needed in ophthalmic pipeline

Increased commitment from the ophthalmic pharmaceutical industry is needed to ensure the future availability of efficacious ophthalmic antiviral agents, according to an ophthalmic virologist.

Jerold S. Gordon, MD, said ocular viruses such as herpes simplex virus-1, herpes zoster, adenovirus and cytomegalovirus receive relatively little attention and resource allocation from pharmaceutical companies compared to the aggressive funding for more high-profile viruses such as HIV, the SARS Coronavirus and the H5N1 bird flu virus.

“Today there are many viruses for which there is an ambitious effort to develop antivirals,” Dr. Gordon said. “At a conference in China, some $1.9 billion has been committed to finding ways of preventing a possible global [bird flu] pandemic.”

Meanwhile, current ophthalmic anti-virals are aging; the most recent drugs in this category were developed more than a decade ago, Dr. Gordon said.

But despite the age of these drugs, some public health officials might not see a compelling need to replace them because the current drugs are still effective, Dr. Gordon said.

Another possible explanation for the lack of interest in developing new ophthalmic antivirals is a perceived lack of return on investment. The world's top selling drugs are oriented toward chronic and lifestyle diseases, Dr. Gordon said, not acute conditions.