Survey: Cataract procedures decreased in ’05

SAN FRANCISCO — The number of cataract surgeries performed in 2005 fell 60,000 from the 2004 level, while the number of LASIK procedures remained relatively unchanged, according to results from the annual survey of members of the American Society of Cataract and Refractive Surgery.

David V. Leaming, MD, and Richard J. Duffey, MD, surveyed 4,645 active U.S. members of ASCRS and received 725 responses (16%) to their 2005 Survey of Practice Styles and Preferences.

The estimated annual volume of cataract surgery was 2.79 million procedures, according to the researchers, down from 2.85 million in 2004. The estimated volume of refractive procedures, including PRK, LASIK and LASEK, also declined slightly, to 928,737 procedures in 2005. The change was less than 1%, and Drs. Leaming and Duffey noted that LASIK growth has been relatively flat since 2001.

Between August and October 2005, one-third of the respondents opted to implant presbyopic IOLs; the other two-thirds indicated they expect to begin implanting the lenses within the next year.

Frozen irrigation solution may alleviate post epi-LASIK pain

A topical, frozen balanced salt solution may reduce pain associated with surface ablation procedures, according to a study.

Bruce C. Larson, MD, assessed the effectiveness of preoperative treatment with frozen balanced salt solution as a means of alleviating the pain experienced within 24 hours after epi-LASIK.

The study looked at a series of 39 consecutive epi-LASIK procedures. The control group consisted of an initial series of 18 eyes that received standard epi-LASIK. A second consecutive series of 21 eyes received 50 drops of frozen balanced salt solution applied directly to the cornea before undergoing epi-LASIK. At day 1 postop, all patients were asked to rate their level of pain on a scale of 0 to 10, and the two groups were compared for the level of postoperative pain control.

For those who had been given the drops preop, the average pain score on a per-eye basis within the first 24 hours was 1.4 on a scale of 0 to 10.

Of the 18 eyes (11 patients) that had not been treated with the frozen solution, the average pain score reported within the first 24 hours was 4. “The results were pretty dramatic,” Dr. Larson said. “This has largely eliminated one of the barriers to surface ablation – pain.”

Nomogram accounts for aberration interactions

A nomogram for laser refractive surgery that accounts for the interactions of certain higher-order aberrations may improve results in PRK and LASIK, according Manoj Subbaram, MD.

The interaction of preoperative higher-order aberrations can have significant effects on sphere and cylinder after laser refractive surgery. “Compensating for these interactions can definitely improve results of LASIK and PRK,” he said.

Dr. Subbaram noted that in the clinical trial data submitted to the Food and Drug Administration for premarket approval for the Bausch & Lomb Zyoptix laser system, “there was only moderate predictability of postoperative refractive error,” with 76% of eyes within ±0.5 D of target.

In an effort to improve this result, Dr. Subbaram and his co-author Scott M. MacRae, MD, analyzed the study results and found that overcorrection was five times more likely in the study than undercorrection. In addition, they found that the eyes with overcorrections had greater amounts of defocus, spherical aberration and third-order root mean square aberrations.

“This gave us a clue that there might be something going on in terms of aberration interaction that affects our postoperative results,” he said.

Eyes in the study with a lot of postoperative positive spherical aberration tended to be hyperopic, Dr. Subbaram said, leading to the hypothesis that defocus is related to spherical aberration. “This is just the tip of the iceberg,” he said. “There are many more interactions.”

The nomogram they devised uses the patient’s preoperative manifest refraction and compensates for the aberration interactions that the researchers “decoded,” Dr. Subbaram said.

The new nomogram was evaluated in a series of 508 eyes, of which 445 underwent LASIK and 63 underwent PRK. The LASIK eyes had a mean preoperative refractive error of –4.5 D, and the PRK eyes had a mean preop refractive error of –6.6 D. All eyes had a high degree of preoperative higher-order RMS, at least 0.5 µm.

At 1 month postoperative, the sphere and spherical equivalent were “pretty much at zero,” Dr. Subbaram said, and all eyes were within ±1 D of plano.

In addition, 94.6% of PRK eyes and 90.5% of LASIK eyes had uncorrected visual acuity of 20/40 or better, he said.

Shared nomogram provides good results in early LASIK

A nomogram based on multiple centers’ pooled data can provide good LASIK results in the early period of using a new excimer laser, a study presented here showed.

The database also allows the surgeon to improve on initial results by constructing his or her own personal nomogram, according to one user of the system.

David A. Wallace, MD, said using the SurgiVision DataLink system after he acquired a WaveLight Allegretto Wave laser reduced his “nomogram angst.” He said the DataLink system is a Web-based, simplified version of the Kezirian Refractive Consultant. It pools data from U.S. sites that are using the Allegretto Wave laser system. According to WaveLight, about 30% of U.S. users of the Allegretto Wave subscribe to the DataLink system.

Dr. Wallace said that in his first 65 LASIK cases performed with the system, in eyes with up to 7 D of myopia, 84% achieved uncorrected visual acuity of 20/20 or better. After gathering follow-up data on his patients for 2 months and building his own personal nomogram, his results improved, with 94% achieving 20/20 or better UCVA, he said.

In the multicenter U.S. trials for regulatory approval of the Allegretto Wave, 91% of comparable eyes achieved 20/20 or better UCVA, he noted.

Dr. Wallace’s enhancement rate also decreased, with 5.4% of eye requiring enhancement with the pooled data nomogram and only 3.2% needing enhancement with his surgeon-specific nomogram, Dr. Wallace said.

Most basal cells in epi-LASIK flaps are not viable

Up to 90% of basal epithelial cells in epi-LASIK flaps may be dead or crucially damaged when they are replaced onto the stroma, a histology study showed. Most superficial and intermediate cells in the flaps may still be viable, however.

Shigeru Kinoshita, MD, described a histologic study he performed on epi-LASIK flaps that were created using three brands of microkeratome: the Gebauer device now distributed by CooperVision Surgical, the Norwood EyeCare Epikeratome and the Moria Epi-K device.

Small peripheral sections of epithelial flaps created by each device were trimmed off with fine scissors immediately after the excimer laser ablation during epi-LASIK. The sections were processed for transmission electron microscopy (TEM) or confocal microscopy.

About half of the 22 samples showed an intact basement membrane on TEM. Staining indicated that 90% of the cells in the basal layer were dead or damaged.

Dr. Kinoshita said the high percentage of non-viable cells in the basal layer was “probably due to mechanical damage from the epikeratome cut.” He said epi-LASIK is a worthwhile surgical procedure, but the instrumentation must be improved to make the basal cells more biologically active.

Telescopic multifocal IOL addresses low vision needs

Gholam A. Peyman, MD, described the development of a two-zone, aspheric, three-lens design for patients with AMD during the Innovators’ Session. Image: Mullin DW, OSN

A small-incision foldable telescopic IOL may significantly improve quality of vision for patients with age-related macular degeneration, according to Gholam A. Peyman, MD. He described the development of a two-zone, aspheric, three-lens design for patients with AMD during the ASCRS Innovators’ Session.

The central optical zone of the new telescopic IOL provides 3X magnification for central vision, and a peripheral zone provides normal peripheral vision.

The anterior element of the lens is a small-diameter (1.5 mm), aspheric lens with high positive power. The posterior element is a larger diameter (6 mm) two-zone lens. The central portion, with a diameter of 1 mm, provides additional negative power for the telescopic zone, Dr. Peyman said. The periphery of the posterior element provides standard IOL power to allow the patient to focus on distant objects.

According to Dr. Peyman’s abstract, theoretical optical evaluation of the telescopic IOL showed that patients achieved 3X angular magnification at a distance of 25 mm. In addition, the peripheral portion of the posterior lens provided focusing for distant objects, as well as peripheral vision for a very wide angle.

“This lens provides unobstructed peripheral field, as well as 3X magnification,” Dr. Peyman said. “Clinical investigation in human trials will start in 6 weeks outside the United States.”

Accommodating lens shows better results than conventional

The eyeonics crystalens accommodating IOL has “measurable improvements in near vision” when compared to conventional IOLs, said Jonathan M. Davidorf, MD.

He described results of an ongoing, non-randomized, unmasked prospective study in 124 eyes of 71 patients who underwent standard coaxial phacoemulsification with IOL implantation. He said comparative studies of accommodating vs. conventional IOLs are rare, making it difficult to counsel patients on which lens to choose.

In his trial, patients were implanted with either the Alcon AcrySof (53 eyes) or the eyeonics crystalens (71 eyes). Best corrected near vision was measured using a Jaeger card through distance manifest refraction. Accommodative amplitude at 1 m was 1.52 for the crystalens and 0.83 for the AcrySof, Dr. Davidorf said. At 3.6 m, values remained the same.

Dr. Davidorf said after patients adjusted to the crystalens, he found uncorrected near vision was more improved than was documented in the study, with a slightly myopic endpoint and bilateral implantation. “In use, it’s even more powerful,” he said. “In the real world, you’re looking out of both eyes.”

Mixing, matching IOLs good option for quality vision

No single lens is ideal for every patient, making mixing and matching IOL technologies viable for better patient satisfaction, said Richard L. Lindstrom, MD.

Dr. Lindstrom, Chief Medical Editor of Ocular Surgery News, and Primary Care Optometry News Editorial Board member, said every IOL technology has plus and minuses, rendering mixing in some cases the best option. He said this is not a new idea, with multifocal/monofocal and monovision contacts regularly combined. A newer idea, the mixing of conventionaly multifocal or accommodating lenses, is yet another option, he said.

“If you mix and match appropriately, you can lead to higher patient satisfaction,” Dr. Lindstrom said.

He said staged implantation provides a “safety net” for the surgeon to guard against possible patient dissatisfaction. He said the process works by first choosing an IOL for the first eye, waiting for feedback from the patient about the quality of vision with that lens at about 2 to 4 weeks postoperative. Then the surgeon chooses the second IOL. If patients were pleased with the first lens, the same lens can be implanted. If they are unhappy with the first lens, a different lens is selected, he said.

Topical NSAIDs may improve vision in IOL patients

Administering keratolac tromethamine 0.4% both preoperatively and postoperatively may improve the visual outcomes for patients who have undergone a multifocal IOL implantation, according to Eric D. Donnenfeld, MD.

Eric D. Donnenfeld

He described a multicenter prospective study to assess the effect of ketorolac tromethamine 0.4% four times daily for 3 days preoperatively and for 3 weeks after multifocal IOL implantation. Results were compared with control patients; emphasis was on quality of vision. About 40 patients had been implanted bilaterally with the ReSTOR multifocal IOL (Alcon), he said.

Uncorrected visual acuity, best corrected visual acuity, mesopic and photopic contrast sensitivity were assessed at 2 weeks and 3 months after the second eye implantation. Lifestyle questionnaires given at 3 months showed the patients who were also given keratolac tromethamine had improved satisfaction with their multifocal IOLs compared to the patients who were not given the NSAID.

Dr. Donnenfeld added that using topical NSAIDs may also help prevent cystoid macular edema (CME).

“There’s a myth that CME is not common, but in fact it is common,” he said. “Preoperative and postoperative topical NSAIDs are important in patients receiving multifocal IOLs. This brings me to the point that we have really raised the bar on how we judge our outcomes. Snellen acuity is important, but quality of vision is the most important.”

Dynamically accommodating IOL a ‘tremendous’ refractive tool, surgeon says

A “clamshell dynamically accommodating” IOL may be an “excellent” device for refractive lens exchange, said Keiki R. Mehta, MD. He said the lens is capable of correcting high myopia and high hyperopia while retaining accommodation.

Dr. Mehta said that the lens provided a reduction in dependency on postop refractive correction, and that the lens should be implanted through a clear corneal incision. He reported on his results from 214 implantations.

“Most of the patients are 20/30 or better and they are very happy with the fact that they have no need for glasses,” he said.

At 42 months, the mean uncorrected visual acuity improved from 6/36 to 6/9 at distance and from J7 to J1 at near. In 87% of the cases, best corrected visual acuity was 6/6; J1 was obtained in 74% of the patients, Dr. Mehta said. IOP ranged from 14.6 mm Hg to 17.5 mm Hg. The mean amount of postoperative accommodation was +2.5 D. Dr. Mehta said no complications were noted.

“It’s a great system,” he said. “We do believe this is the lens of the future.”

Mixing multifocal IOLs results in better overall vision

Combining two different multifocal IOLs in one patient can result in a high rate of spectacle freedom and patient satisfaction, said Frank A. Bucci, Jr., MD.

Dr. Bucci initiated a study in which one cohort received the ReSTOR IOL (Alcon) in both eyes and a second cohort received the ReSTOR lens in one eye and the ReZoom lens (Advanced Medical Optics) in the contralateral eye. The ReSTOR-only group comprised 55 patients with a mean follow-up of 27 weeks. The mixed group comprised 39 patients with a mean follow up of 12 weeks.

In the ReSTOR-only group, 21 patients had cataracts and 24 had refractive lensectomies. “Implanting the ReSTOR in the second eye improved reading and caused no added halos,” he said.

The first group had a near visual acuity of J1, while the mixed-lens group had a near VA of 1.07, Dr. Bucci said. There was no statically significant difference at near, he said.

No statistically significant differences in bilateral uncorrected near vision were observed, he said.

For near vision, ReSTOR was excellent in bright light for small pupils, while the ReZoom was very good in moderate light for medium pupils, Dr. Bucci said. For intermediate vision, ReZoom was excellent, while ReSTOR sacrificed intermediate for fine detail at near, he said. For distance, ReZoom had excellent bright daylight vision, while ReSTOR had less light phenomena at night.

In the discussion following his paper presentation, Dr. Bucci said that he had started using ReZoom in the nondominant eye but switched to using ReZoom in the dominant eye and ReSTOR in the nondominant eye because he had heard too many complaints from patients about unilateral issues.