This article is more than 5 years old. Information may no longer be current.
Annual survey finds LASIK volume up more than 25%
Click Here to Manage Email Alerts
WASHINGTON – The volume of LASIK procedures grew 26% from 2003 to 2004, according to an annual survey of practice preferences presented here at the American Society of Cataract and Refractive Surgery meeting.
Other notable findings of the survey of U.S. members of ASCRS included an overwhelming preference for acrylic IOLs, a unanimous interest in accommodating IOLs and a near-doubling of the use of clear corneal incisions from 5 years ago among the respondents.
David V. Leaming, MD, sent his annual survey on general ophthalmic trends to 6,296 physicians; 773 returned the questionnaire. He reported the results of the survey here in a presentation and a poster.
According to Dr. Leaming, in 2004, 62% of survey respondents used topical plus intracameral anesthesia in cataract surgery.
Over the 5-year period from 1999 to 2004, the use of clear corneal incisions almost doubled, from 40% to 72%, according to survey responses. Surgeons said they prefer a metal blade to a diamond blade for the cataract incision by a two-to-one ratio, Dr. Leaming reported.
As in recent years, acrylic IOLs remained the preferred IOL material among respondents, followed by silicone, PMMA and hydrogel. More than half the respondents — 57% — said they prefer a single-piece foldable IOL.
For use with ultrasmall-incision cataract surgery in the future, 38% of respondents said an acrylic lens is the most promising IOL, and 29% of respondents said an injectable lens material holds the most promise.
In a change from last year, 61% of respondents said they prefer implanting a clear IOL rather than a blue-light-filtering IOL. In 2003 47% reported preferring clear lenses.
The survey also addressed refractive surgery topics. As noted above, respondents reported an increase in LASIK volume by 26% in the year since the 2003 survey.
Seventy-five percent of respondents said 250 µm is the threshold for the residual stromal bed below which they would not perform LASIK.
Asked about what refractive procedures they were interested in adopting, 84% of respondents said they were not interested in scleral expansion, 49% were not interested in conductive keratoplasty, 54% were not interested in LASEK and 50% were not interested in phakic IOL implantation.
Respondents said they charge an average $500 additional to perform customized LASIK over their fee for conventional LASIK.
Dr. Leaming noted that in 2003 respondents said only 9% of patients were offered wavefront LASIK. In 2004, every patient was offered the option of wavefront, he said.
Regarding glaucoma, the survey posed a series of scenarios and asked what drug the respondents would prescribe. For first-line therapy in a 45-year-old patient, 60% said they would prescribe prostaglandins if the patient was blue-eyed with no cardiopulmonary complications, and 77% would prescribe prostaglandins if the patient had brown eyes and no cardiopulmonary complications. For a blue-eyed patient with a history of cardiopulmonary complications 83% would prescribe prostaglandins, and for a brown-eyed patient 94%.
Regarding medical liability, 17% of respondents said they pay a malpractice insurance premium of $10,000 per year; 14% each said they pay $7,500, $12,500 or $15,000.
Other highlights, originally published on the OSN Supersite, from the refractive surgery and cataract/IOL sessions at the ASCRS meeting are summarized in the rest of this article. Presentations from the glaucoma and cornea sessions are covered in separate articles beginning on page 1, and business news from the meeting can be found in the Ophthalmic Business section.
| Challenge Cup Session |
|
|
|
|
|
|
Manus C. Kraff, MD, refereed the Challenge Cup Session at ASCRS. Ophthalmologists formed debate teams to argue pros and cons of various refractive and cataract procedures. Here the GlobeBusters, captained by Paul S. Koch, MD, (right) and the White House Warriors — Presidents of the United Capsules of America, captained by Bradford J. Shingleton, MD (left) debated cataract strategies.
![[bar]](/~/media/images/shared-images/gradient_325_4_90709.gif)
Refractive Surgery
IntraLase for enhancement
The IntraLase FS laser can be programmed to perform a side-cut for late LASIK enhancement that avoids some of the problems with flap lifting, said Jon G. Dishler, MD.
Dr. Dishler reported on the use of the FS laser to create a new flap in eyes undergoing enhancement at 3 to 7 years after initial LASIK surgery. He said the “side-cut only” setting on the IntraLase can create a flap deeper and smaller in diameter than the original keratectomy.
All flaps lifted easily, had smooth interfaces and healed uneventfully, Dr. Dishler said. Postoperative day 1 visual outcomes were “excellent,” he said.
“Ten years ago, we would wait about 6 months to do enhancement. Five years ago, relifting became ‘standard of care,’ but we saw a high incidence of epithelial ingrowth,” Dr. Dishler said. This new application of the FS laser allows easy access to the original, smooth corneal bed, he said
“Centration is key” when making the new cut, he said. Dilating the pupil aids in centering the new incision because it allows the surgeon to see the old cut. Overlap of the two cuts has not been a problem, as it has been with making a second flap with mechanical microkeratomes, he said.
IntraLase lamellar keratoplasty
Lamellar keratoplasty using a femtosecond laser can be a viable alternative to penetrating keratoplasty in appropriate candidates, according to Ramòn Naranjo-Tackman, MD.
The IntraLase FS laser allows creation of both donor and recipient anterior corneal lamellae in a “clean, fast, repeatable” 35-minute procedure that has resulted in visual improvement in most eyes, Dr. Naranjo-Tackman said.
He discussed his prospective evaluation of the procedure in 16 eyes of 16 contact-lens-intolerant patients. The preoperative uncorrected visual acuity in the eyes in the study was 20/200 or worse. Postoperatively, UCVA in 75% of eyes improved by at least 2 lines of acuity, and in 50% of eyes it improved by “up to 4 lines,” he said. The 8.5-mm grafts were clear in all eyes at 3 months postop.
Dr. Naranjo-Tackman said he used eight interrupted sutures combined with an eight-point running suture in all eyes. He said more study may be needed to determine the best time for suture removal, but it probably should not be done before 6 months postop.
Among the advantages of the lamellar procedure is the preservation of the recipient’s corneal endothelium, he said.
Femtosecond vs. conventional
No statistically significant differences were seen in the outcomes of LASIK with flaps created by either a femtosecond laser microkeratome or a conventional blade microkeratome, according to Maria R. Chalita, MD.
Dr. Chalita discussed the results of a study comparing the IntraLase FS laser and the Moria M3 microkeratome. She said there were no statistically significant differences between the results with the two microkeratomes regarding postoperative best corrected visual acuity, spherical equivalent and higher-order aberrations.
Dr. Chalita compared 129 eyes that underwent wavefront-guided LASIK after flap creation with the IntraLase with 282 eyes that underwent wavefront-guided LASIK after flap creation with the Moria M3.
The differences between the two groups were minimal, she said. Both groups had increases in spherical aberration, but the difference was not statistically significant. There were also slight increases in vertical coma in the IntraLase group and horizontal coma in the Moria group, she said.
MEL 80 for myopic LASIK
A new wavefront-optimized excimer laser from Carl Zeiss Meditec is showing comparable results to other refractive lasers, and company investigators are “eagerly awaiting” final results from the laser’s clinical trials, said Steven J. Dell, MD.
Dr. Dell is an investigator in a U.S. clinical trial of the MEL 80; he and colleagues are evaluating the results of LASIK using the device in 360 eyes at five U.S. sites. Dr. Dell presented preliminary results of the trial.
Enrolled patients have myopia up to –10 D and –3.8 D of astigmatism, Dr. Dell said. the wavefront-optimized procedure is fast, with ablation taking an average of 3 seconds per diopter of correction, he said.
Early results of the study show that 93% of eyes achieved 20/20 or better for uncorrected visual acuity at 6 months; 63% achieved 20/16 or better UCVA; and 27% achieved 20/12 or better UCVA, Dr. Dell said.
In terms of safety, 6% of eyes lost one line of vision, while 34% gained one line. No patients lost two or more lines of vision, he said.
Wavefront-guided, wavefront-optimized
Wavefront-guided LASIK using the Allegretto Wave laser system had the same efficacy and safety profile as wavefront-optimized LASIK with the same laser in a clinical trial, but the wavefront-guided procedure induced fewer higher-order aberrations, according to results presented here.
At a symposium sponsored by laser manufacturer WaveLight, Stephen F. Brint, MD, FACS, presented results in 240 eyes that underwent either wavefront-optimized or wavefront-guided LASIK with the Allegretto Wave since September 2004. Wavefront-guided LASIK was performed in 122 of the eyes. Eyes with up to –7 D of sphere and –3 D of cylinder were randomized to receive treatment with either wavefront-optimized or wavefront-guided profiles, Dr. Brint said.
“More than 90% of patients in both groups achieved 20/20 vision without glasses or contact lenses, and more than 60% achieved 20/16 or better,” Dr. Brint said at the symposium. “For patients with few pre-existing higher-order aberrations, both platforms performed nearly identically.”
Guy M. Kezirian, MD, FACS, president of SurgiVision Regulatory Consultants Inc., the group that performed the analysis, said, “Preliminary results suggest that wavefront-guided treatments may offer certain advantages to a minority of patients with significant preoperative higher-order aberrations, such as trefoil and coma.”
A second study is under way to evaluate the safety and effectiveness of the Allegretto Wave for the treatment of mixed astigmatism, according to WaveLight.
Intraoperative pachymetry
The WaveLight Concerto 500-Hz laser includes an onboard pachymeter that allows surgeons to measure flap thickness and residual stromal thickness intraoperatively after flap creation and surface ablation, according to Matthias J. Maus, MD.
“The optical no-touch pachymetry feature takes rolling, continuous measurements during surgery. This enables surgeons to truly gauge flap thickness and residual stromal thickness postop,” Dr. Maus said at the ASCRS meeting.
Dr. Maus said that the online pachymeter provides valuable information regarding the biomechanics of the cornea during LASIK.
“Online pachymetry allows us to make intraoperative modifications and prevent complications,” he said.
In a 3-month study of 50 eyes that underwent LASIK with the Concerto laser, Dr. Maus found “little difference between planned ablation depth and measured ablation depth,” when comparing outcomes to measurements from the Pentacam (Oculus) pachymeter. He said the online WaveLight pachymeter produced accurate measurements, with a standard deviation of 30 µm. Flap thickness varied between 122 µm and 157 µm, he said.
The WaveLight Concerto laser is a “concept” laser unveiled by the company last year. It is not in wide distribution. A WaveLight spokeswoman said only two Concerto lasers are in use in the world, including the one used by Dr. Maus in this study.
Mitomycin in PRK
Use of mitomycin-C in patients undergoing PRK can cause endothelial cell loss and increased patient discomfort, according to Alberto J. Morales, MD.
Dr. Morales evaluated the effects of mitomycin 0.02% after PRK in 18 eyes of nine patients. All patients needed more than 75 µm of ablation depth and did not qualify for LASIK.
Endothelial cell counts were obtained preoperatively and at 1 and 3 months after PRK, Dr. Morales said. Patient discomfort was evaluated at 1 day and 1 week and at months 1 and 3.
Mitomycin-C (MMC) was applied to one eye of each patient for 30 seconds; the patient’s other eye received only saline solution.
The eyes treated with MMC had significantly more discomfort as reported by the patient. Endothelial cells counts were “slightly reduced” and corneal pachymetry was increased in the eyes receiving MMC compared with the eyes that had saline, he said.
“We are worried about the significant differences in endothelial cell loss with MMC,” he said.
Dr. Morales noted that these results are preliminary, and he said it is too early to determine the long-term effects of MMC. Longer follow-up is needed, and the researchers are considering evaluating more patients
Thin flap consistency
A new microkeratome head cut thin flaps with a high degree of consistency, according to Richard J. Duffey, MD.
The predictability of flap thickness with the 100-µm head for the Moria LSK-One was better than published reports of other manual microkeratome heads intended to cut thicker flaps and comparable to results with the femtosecond laser flapmaker, Dr. Duffey said.
He evaluated the thickness of the flap created with the LSK-One in 42 consecutive eyes intraoperatively by subtraction ultrasound pachymetry – calculating the difference between the central corneal thickness before flap creation and the residual stromal bed after the flap was lifted.
Average flap thickness with the microkeratome, which is intended to cut 100-µm flaps, was 107 µm, with a range of 82 µm to 137 µm. Nasal hinge chord length ranged from 3.12 mm to 5.75 mm, he said.
Dr. Duffey said patients in the study experienced fast visual recovery with minimal rise in IOP. On the first day postoperatively, 76% of eyes achieved 20/20 or better visual acuity. Postoperatively, there were no slipped flaps, no diffuse lamellar keratitis and no epithelial defects.
“Visual recovery is rapid, epithelial risks minimal, IOP rise shorter, efficiency superior and the cost is nominal relative to femtosecond laser technology,” he said.
Aberrations, visual complaints
Patients’ complaints about their vision were not related to their pupil sizes or levels of higher-order aberrations, according to a study.
Shachar Tauber, MD, administered a questionnaire to 37 patients before refractive surgery to determine whether higher-order aberrations were clinically significant across pupil sizes.
”There was no correlation between subjective visual complaints, pupil size or degree of myopia [preoperatively] and higher-order aberration measurements,” he said.
Dr. Tauber used the questionnaire to assess patients’ subjective visual complaints, and he also recorded pupil sizes and degrees of refractive error. All patients had a BCVA of at least 20/20, he said.
“We found … [that] eyes with natural super-vision (better than 20/15) had the same number of higher-order aberrations as those who had specific visual complaints,” he said.
The average pupil size was 5.9 mm in his patient group, the mean spherical equivalent was –3.74 D, and the mean root mean square of higher-order aberrations was 0.43 µm, he said.
“We could not correlate higher-order aberrations to visual differences or to night driving,” he said.
The “smallest” correlation was found between higher-order aberrations and visual complaints in patients who wore glasses and had a larger pupil diameter (greater than 6 mm) and in those who wore contact lenses but had smaller pupil diameters.
Cataract Surgery
IOL removal survey
Decentration and dislocation were again the most common reasons for IOL removal in 2004, according to an annual survey of foldable IOL complications.
Nick Mamalis, MD, who conducted the survey, said these findings on decentration have been “consistent for the 7 years of our survey.”
Dr. Mamalis said that to prevent decentration and dislocation, good surgical techniques are essential, and surgeons should “make sure that the lens is well centered.”
He said the frequency of other complications depended upon what type of IOL was used.
“Ongoing vigilance is needed” regarding new IOL materials, he said.
Bag/sulcus piggyback IOLs
Placing one IOL in the capsular bag and one in the ciliary sulcus is usually the safest approach to “piggybacking” IOLs, according to Y. Ralph Chu, MD. Dr. Chu shared this and other pearls on piggyback IOL techniques at the Future Trends in Ophthalmology meeting, held during ASCRS.
“Implanting a lens in the bag and one in the sulcus prevents endothelial cell migration and protects against interlenticular opacities, which are the biggest complication of the piggyback technique,” Dr. Chu said.
Piggybacking, or using two IOLs with complementary powers to achieve optimum visual performance, is often used as a surgical strategy for patients in need of a lens power adjustment after cataract surgery and in patients who need very high lens powers, he said.
“Single high-power lenses can result in unacceptable spherical aberration, so sometimes aligning the optical centers of two IOLs with high [total] dioptric power will provide better optical results,” Dr. Chu said.
He recommended that surgeons use silicone lenses for piggybacking because they provide better resistance to interlenticular opacification. The haptics of the two lenses should be placed in parallel to maintain chamber stability, he said.
The Future Trends in Ophthalmology meeting was sponsored by SLACK Incorporated, the publisher of the OSN, and supported by an educational grant from Advanced Medical Optics.
NSAID in pipeline for cataract surgery
A new non-steroidal anti-inflammatory drug had significantly higher cure rates, lower inflammation scores and fewer treatment failures in a trial comparing it to vehicle, said investigator Stephen S. Lane, MD.
Dr. Lane discussed clinical study results with nepafenac 0.1% in a presentation at ASCRS.
“Nepafenac is a prodrug with rapid corneal penetration that converts to amfenac in the eye,” he said. According to the drug’s developer, Alcon, nepafenac is the first prodrug NSAID being developed for ophthalmic use.
Alcon, which plans to market nepafenac as Nevanac, announced during the ASCRS meeting that the Food and Drug Administration has accepted the company’s new drug application for the NSAID for the treatment of pain and inflammation associated with cataract surgery. The application has been granted priority review.
In the study presented by Dr. Lane, 476 patients were dosed with nepafenac three times daily on the day before cataract surgery, the day of surgery and for 14 days postoperatively.
The cure rate was 62.6% with nepafenac, compared with 17.2% for vehicle by the last follow-up, he said. During all postoperative visits, patients dosed with nepafenac showed a significant reduction in cells, flare, and cells plus flare, he said.
“By day 1, those on nepafenac had a twofold improvement in cells and flare [over] those on vehicle,” he said.
During a question-and-answer period, Dr. Lane said he believes nepafenac may be used as a standalone drug to control inflammation in patients who cannot take steroids, but in other patients it would probably be an adjunct to steroids.
According to an Alcon press release, in clinical trials more than 80% of patients treated with Nevanac suspension were pain-free on day 1, compared with 40% to 50% in a placebo group. By day 14, approximately 95% of patients were pain-free when treated with the drug, compared with 45% to 60% of patients in the placebo group. Regarding inflammation control, more than 85% of patients treated with Nevanac suspension had no clinically significant inflammation at day 14, compared with approximately 49% of patients in the placebo group.
MICS astigmatism
Incision size played no role in the degree of surgically induced astigmatism in a study presented here by Eduardo A. Franca Alves, MD.
Dr. Alves studied 36 eyes of 30 patients undergoing cataract surgery to determine the effect of incision size on induced astigmatism. He performed coaxial phacoemulsification in 23 eyes and microincision cataract surgery (MICS) in 13 eyes. The mean incision size in the eyes undergoing coaxial phaco was 3.21 mm and in those undergoing MICS 2.4 mm.
“There was no difference in induced astigmatism even when the incision size is different,” he said.
It is the internal incision dimension, not the external size of the cut, that determines the level of induced astigmatism, he said.
Hydrochop and MICS
A chopping instrument that uses the power of water to split open the nucleus makes microincision cataract surgery easier and faster in nuclei of any degree of hardness, according to Hideharu Fukasaku, MD, the developer of the device.
Dr. Fukasaku said the chopper has two distally placed ports that allow waterjets to be generated deep within the cataractous nucleus. The chopper is first pushed into the lens to split it, then pushed again into each of the halves that are formed by the split, ultimately forming four quadrants that can be easily emulsified using phaco power.
The procedure is performed through two 1.4-mm incisions. One of the incisions is enlarged to 3 mm for the insertion of a standard 6-mm acrylic IOL because “we do not yet have an ideal IOL to go through a 1.4-mm incision,” Dr. Fukasaku said.
He said the technique has a number of advantages over other microincision cataract surgery (MICS) techniques.
“The surgeon can always see the instruments,” he said. “Blind maneuvering behind the iris is not necessary with the hydrochop technique.”
In addition, the hydrochop technique is more useful, safer and faster than other MICS techniques for bimanual phaco, he said.
Phaco-chop with micropulse
|
Images: Liberatore MD |
A phaco-chop technique using micropulse ultrasound and varying duty cycles used less energy than a standard continuous phaco technique, said Steven H. Dewey, MD.
“The chop surgical technique, together with the ultrasound modifications, really makes a difference,” Dr. Dewey said.
He presented the results of a study on 335 eyes comparing two techniques: continuous ultrasound phacoemulsification with the Advanced Medical Optics Sovereign WhiteStar System using a divide-and-conquer cataract extraction technique, and micropulse or “varied” ultrasound phacoemulsification with a chop technique.
“The micropulse ultrasound setting, marked by small bursts of energy followed by small rests, is safer for the patient because it reduces the risk of wound burn,” Dr. Dewey noted. For patients undergoing the chop technique with micropulse ultrasound, the duty cycle was reduced to between 25% and 35%, he said.
Dr. Dewey found that the divide-and-conquer group with continuous ultrasound “demanded far more” energy than the chop group with varied ultrasound. In fact, Dr. Dewey said, the continuous ultrasound group required three times as much energy as the variable ultrasound group.
“There was a 3-to-1 ratio of power efficacy after all variables were considered,” he noted.
While the varied ultrasound group required less energy than the continuous group, Dr. Dewey said that the chop technique slowed the procedure down, adding an extra 12 to 15 seconds per case.
Accommodating IOL
An accommodating IOL produced “relatively small” objective accommodative change in clinical trials, but investigators said the level of patient satisfaction with the IOL was high.
“Patients had an objective improvement in their accommodation of about 0.6 D, but their subjective amplitude of accommodation was 2.1 D or greater,” Sunil Shah, MD, FRCS, told attendees. He presented results a 6-month study of 65 patients implanted with the Kellan Tetraflex KH3500 lens from Lenstec.
Dr. Shah said that one patient in particular — his father — was “very happy” with his visual outcomes.
A 200-patient study of the KH3500 IOL, presented by Sanjay Mantry, MD, FRCS, found similar results.
“Patients’ subjective grading of their functional accommodation was much higher compared to objective results,” Dr. Mantry said. Patients in his study reported having a mean functional accommodation of 2.1 D, ranging up to 5 D of reported accommodation. Postoperative BCVA in the trial averaged approximately 20/25.
Deepak K. Chitkara, FRCOphth, said that 75% of patients in a 138-patient study reported being “very satisfied” with their vision after implantation with the KH3500 lens, and more than 45% of patients reported achieving functional vision that was equivalent to more than 3 D of accommodation. Uncorrected distance visual acuity of 20/40 was achieved in 70% of patients, he said.
Regarding the investigators’ observation that patients implanted with the KH3500 lens experienced little accommodative shift as measured objectively — under 1 D in most cases — but reported significant subjective improvement, Dr. Shah said, “We are a long way from seeing how these lenses actually work, but the patients continue to be happy, and that’s really what matters.”
‘Aberration-free’ IOL
An IOL designed to induce no spherical aberration in the eye has produced good visual results in patients in a preliminary study, according to a speaker here.
In a study of the Bausch & Lomb SofPort AO IOL in 105 patients, 97% of patients were happy with their visual outcome after surgery, said Louis D. Nichamin, MD.
“These patients reported as good or better than expected visual results,” Dr. Nichamin said.
Additionally, in a subset of 49 patients who were implanted with the SofPort in one eye and a conventional IOL in the fellow eye, most patients preferred the visual performance of the eye implanted with the SofPort lens, he said.
“[Other] aspheric IOLs induce negative spherical aberration to cancel out the positive spherical aberration in the eye,” he said. “But the SofPort AO Aspheric lens is aberration-free. It’s a neutral lens that doesn’t impart any asphericity.”
While a small amount of spherical aberration in the eye can be beneficial to vision by improving depth perception, Dr. Nichamin said, excessive spherical aberration can disrupt quality of vision. Standard IOLs have been found to induce positive spherical aberration (in addition to the spherical aberration that is naturally occurring in the eye). To counteract this effect, aspheric IOLs with negative spherical aberration were developed, Dr. Nichamin said. A lens with neutral spherical aberration, such as the SofPort AO, may provide similar benefit, he noted.
To “see if this technology really works,” Dr. Nichamin has begun enrollment in a 12-month randomized trial to compare the efficacy of the SofPort lens to other aspheric IOLs currently on the market.