EyeNet Magazine


 
News in Review
A Look at Today's Ideas and Trends
By Linda Roach, Contributing Writer
Edited by Brian A. Francis, MD
 
 

• Objective Comparison of AMD Treatments
• Intracameral Avastin vs. Neovascular Glaucoma
• A Laser Alternative for Presbyopia Correction
• Review of the Latest Devices for Presbyopia

It’s not long before an anticipated 28,000 Joint Meeting attendees from all over the world will converge on Las Vegas to learn what’s hot in ophthalmology. This month, News in Review highlights a few papers from the 2006 Joint Meeting of the Academy and the Asia Pacific Academy of Ophthalmology in order to prepare you for the meeting. For a comprehensive listing of papers and posters, see the insert in this issue.

Retina Papers

Objective Comparison of AMD Treatments

With the rapid proliferation of drugs for age-related macular degeneration, how is an ophthalmologist to know which treatment to use? By how large a contribution visual improvement makes to patients’ quality of life, said Melissa M. Brown, MD, MBA, and Gary C. Brown, MD, MBA.

For the last decade, the Browns have been part of an international group gathering data on the “time tradeoff” values that people put on various aspects of health: that is, how many years of life they would give up in order to avoid a health condition. “It has been fascinating to see how important vision is to people when compared with other health issues. The numbers that we have are so clear,” said Dr. Melissa Brown. “When you ask them about severe AMD, the value they put on it is on par with being bedridden, incontinent and in need of constant care after a catastrophic stroke.”

In the final paper1 of Monday’s retina session, the Browns will report on their side-by-side comparisons of the value of AMD treatments, based on a model that combines the patients’ health-utility valuations and the results of clinical trials.

"Our model takes the very best evidence for efficacy and elevates it to the level where physicians can use it to objectively value the different pharmaceutical interventions,” she said.

The eventual goal is to provide direct comparisons of the quality-of-life gains demonstrated among AMD treatments (improvements range from 3 to 8 percent). As the valued assessments are only as strong as the clinical data upon which they are based, reliable conclusions about Avastin first require controlled studies with adequate follow-up, she said.

The Browns’ work is based on time-trade-off data gathered over the last decade from thousands of people in the United States and internationally. (Currently, they are directing additional quality-of-life research in Britain, Chile and Italy.) The changes in quality of life from different trade-offs may be expressed in quality-adjusted life years, or as a percentage change in the quality of life.

The previous gold standard for slowing visual loss from AMD, laser photocoagulation raised the average patient’s quality of life by 3.1 percent, the Browns report in their submitted abstract. (This compares with 3.8 percent from using statin drugs to avoid heart attacks, Dr. Melissa Brown said.)

The quality-of-life gain roughly doubled with AMD drug therapy: 5.8 percent for Macugen (pegaptanib), and 8.1 percent for photodynamic therapy (Visudyne).

Preliminary assessment of currently available public data show Lucentis provides a much higher quality-of-life improvement, in the range of 17 percent. However, she added that further analysis of those data is being done. Clinical trial data on Avastin (cited in error in the published abstract) are not available. Excited by anecdotal results with Avastin, a number of ophthalmologists are gathering patient series, but results known to Dr. Brown are only at the three month follow-up point. “

With value-based evaluations we can compare efficacy data from different trials and present the data with a common denominator in terms of value to patients with AMD,” Dr. Brown said. “It is as if we can compare apples and oranges and tell which patients prefer.”

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1 Value of interventions for neovascular macular degeneration. Monday, Nov. 13, 11:45 a.m., Venetian Ballroom J.

Glaucoma Papers

Intracameral Avastin vs. Neovascular Glaucoma

Avastin: It’s not just for retinas anymore. One of the most devastating conditions that appears to be successfully treated or prevented with this VEGF-blocking drug (bevacizumab) is neovascular glaucoma, caused by iris neovascularization. Two papers on this topic will be presented Tuesday morning, in Venetian Ballroom H.1,2

Neovascular glaucoma often is so aggressive and painful that the patient either loses the eye or it is left blind.

However, Kakarla V. Chalam, MD, PhD, associate chairman of ophthalmology at the University of FloridaJacksonville, and colleagues will report on 14 patients whose iris neovascularization regressed in all patients with weekly to monthly doses of 1.25 mg/0.05 ml of Avastin intracamerally.

"Not only did the existing neovascularization regress, but we also have universally seen a decrease in the appearance of new vessels,” Dr. Chalam said. “Resolution of the glaucoma has not always followed, but we have not lost an eye, which is very unusual in these patients. Only one patient required surgery, and the rest have IOP control with medication.”

The best results came in patients in the earliest stages, grade 1 or 2, and the researchers will be looking for a correlation with the VEGF levels measured before therapy. Patients with more advanced disease had fibrous synechiae in the angle that explained why IOP did not resolve after the vessels regressed, he added.

In the other study, Dallas retina specialists Gregory F. Kozielec, MD, and Maurice Syrquin, MD, gave intravitreal injections of Avastin to 35 patients with central retinal vein occlusion. Although neovascular glaucoma is a known devastating complication of CRVO, the injections were intended to address the patients’ macular edema, said Dr. Kozielec, a clinical assistant professor of ophthalmology at University of Texas, Southwestern. The median number of injections was two, and none of the patients developed neovascular glaucoma.

"We tried this because of the risks to eyes like these if we try to treat the macular edema with an intravitreal steroid,” he said. “In my experience the usage of intravitreal steroids in these patients has had about a 30 percent chance of steroid-induced glaucoma developing. That could add further morbidity to an already compromised eye.”

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1 Incidence of neovascular glaucoma following intravitreal Avastin injection for central retinal vein occlusion. Tuesday, Nov. 14, 8:54 a.m., Venetian Ballroom H.
2 Intracameral Avastin dramatically resolves iris neovascularization and reverses neovascular glaucoma. Tuesday, Nov. 14, 9:06 a.m., Venetian Ballroom H.

Refractive Surgery Papers

A Laser Alternative for Presbyopia Correction

Refractive surgeons looking for a way to optimize their patients’ vision without the complicated measurements of wavefront-based procedures will have a chance to hear two-year data for an alternative technique that addresses the issue of presbyopia: PASA, or pseudoaccommodative advanced surface ablation.

Instead of adjusting the ablation based on measurements of minute aberrations in the optical wavefront as it passes through the eye, PASA is aimed at keeping the cornea aspheric and at improving its negative Q-value, or prolate shape (higher refractive power at the center, lower at the periphery) even as the eye’s refractive error is corrected.

Koller et al. reported this year1 that this topographically based custom approach gave patients with up to –9 D of myopia and 2.5 D of astigmatism visual acuity that was clinically equivalent to that from wavefront-based ablation. With up to –5 D of myopic correction, corneal asphericity was better with custom-Q treatment, they reported.

Roberto Cantú, MD, medical director for CVL Laser Vision Correction in Puebla, Mexico, said his Monday morning presentation will include 18 to 24 months of follow-up in 200 presbyopes on whom the PASA algorithm was used.2 The ablation didn’t make the patients better able to accommodate with their crystalline lenses, but testing nonetheless showed improvement in their near visual performance, according to earlier data presented at the World Ophthalmology Congress in February.

But Dr. Cantú dismisses the notion that this improvement is caused by a multifocal cornea.

"In multifocal cornea you have zones of different refractive powers on the postop topography,” Dr. Cantú said. “With PASA we get a more uniform, prolate cornea on our average group of patients, including the myopic group—in which usually the postop standard for correction results is a more oblate cornea and increased spherical aberration.”

Dr. Cantú said the PASA method is not tied to any particular excimer laser.

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1 J Cataract Refract Surg 2006;32:584–589.
2 Pseudoaccommodative advanced surface ablation: Objective quality of vision in presbyopic and nonpresbyopic patients. Monday, Nov. 13, 11:35 a.m., Venetian, Veronese, Room 2401B.

Cataract Papers

Review of the Latest Devices for Presbyopia

Now that the CMS rules have changed, it’s a new world in cataract surgery. There’s no question that presbyopia correction is at center stage.

The CMS ruling, which allows cataract patients access to presbyopia-correcting IOLs, also allows cataract surgeons “independence from Medicare and third party payers,” said Mark Packer, MD, clinical associate professor of ophthalmology at Oregon Health & Science University. “

This is an opportunity that all cataract surgeons should embrace.” However, he cautioned, “There are challenges to implementing presbyopia correction within a cataract practice. This is a new and different approach. In a way, it holds us to a higher standard. We’re offering an enhancement—and we must know what we’re doing.”

As Academy chairman of the Cataract Papers committee, Dr. Packer said that this year’s free papers will offer cataract surgeons clinical information and practical tips, “from how best to utilize all of the presbyopia- correcting technologies—refractive, diffractive and accommodating—to information on investigative lenses that are in clinical studies.”

For example, one paper will present experience with unilateral implantation of the ReStor (Alcon) IOL. “All of the previously published data are on bilateral implantation,” Dr. Packer noted. “Is unilateral implantation OK? What do you tell patients?”

Similarly, the paper on the “mix and match” technique addresses a “very hot topic,” he said. “The published data are on bilateral implantation of the same lens. What can we expect with mix and match? Is this approach a benefit to patients?”

Overall, he said, “These papers present information that can be put to use the day the meeting ends.”

The papers will be presented one after another from 10:45 to 11:50 a.m., Tuesday, Nov. 14, in the Venetian, Veronese, Room 2401B.

—Jean Shaw

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