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ASCRS members adopting latest refractive advances, survey finds
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SAN DIEGO — U.S. refractive surgeons are increasingly adopting the latest advances in surgical techniques and technology, according to a 2006 survey of members of the American Society of Cataract and Refractive Surgery.
Richard J. Duffey, MD, presented the results of the 2006 survey of trends in refractive surgery. The data included responses from 628 people, or 13% of the 4,797 ASCRS members.
In 2006, 10% of respondents indicated that they did not perform wavefront-guided ablations, “which implies or says that 90% of us do custom ablations in our practice — pretty rapid growth,” Dr. Duffey said. For comparison, 26% of respondents to the 2005 survey indicated that they did not perform wavefront-guided ablations, according to the study.
In addition, LASEK/epi-LASIK saw a dramatic increase in volume, with about 207,000 procedures performed in 2006 compared with about 33,000 procedures in 2005.
The survey also found that, for the first time, more surgeons would use phakic IOLs (27%) over LASIK (20%) for a 30-year-old patient with 10 D of myopia. LASIK remained the preferred treatment for a 45-year-old with 3 D of hyperopia.
About 22% of respondents indicated they have undergone modern refractive surgery themselves, which is about four times the penetration of the general public, Dr. Duffey said.
Regarding microkeratomes, use of IntraLase (Advanced Medical Optics) increased to 17% in 2006 compared with 13% in 2005. “But Moria still has about a 25% share, and the Hansatome/Zyoptix (Bausch & Lomb), about 40%. So mechanical microkeratomes are still winning out in the present day,” he said.
Kelman lecturer: Key to PCO prevention lies in capsular bend, accommodative IOLs
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Images: Altersitz K, OSN |
In the future, the cataract surgeon’s ability to protect against posterior capsular opacification will hinge upon innovative new designs and placement of IOLs, according to the surgeon who delivered the Charles D. Kelman Innovator’s Lecture.
Okihiro Nishi, MD, described his theory behind avoiding posterior capsular opacification (PCO) and introduced his latest idea for an accommodative lens design at the meeting.
“The capsular bend induces contact inhibition of migrating lens epithelial cells regardless of materials of an IOL,” Dr. Nishi explained, showing images and diagrams of both round- and square-edged IOLs.
He said that without this bending effect, the cells can migrate to the posterior chamber and cause PCO. He explained that bending is best caused by square-edged IOLs but is not guaranteed.
Next, Dr. Nishi introduced his novel design combining one posterior and one anterior square-edged IOL and filling the space between with gel. The anteriorally placed IOL is designed with a hole through which the gel can be inserted. The hole rotates to lie under the iris and prevent leakage, he said.
In theory and in a rabbit model, the accommodation occurs with the forward movement of the anterior IOL. Dr. Nishi said the next step is to test the theory in a primate.
“In conclusion, the procedure using the novel accommodative IOL securely prevented leakage,” he said. “The procedure is simple, safe and highly reproducible. … It can be a breakthrough.”
Cornea-based Refractive Surgery
Equivalent incidence of dry eye found after SBK, PRK
Eyes treated with sub-Bowman’s keratomileusis had an equivalent incidence of dry eye as those treated with PRK at 6 months follow-up, according to a surgeon.
“Additionally, SBK eyes had significantly less dry eye symptoms prior to the 1-month visit, which leads to more comfort with the patients in that initial stage,” Erin D. Stahl, MD, said.
Dr. Stahl and colleagues examined 50 non-dry eye patients who underwent SBK in one eye and PRK in the contralateral eye. SBK flaps were created with an IntraLase femtosecond laser with a target thickness of 100 µm, she said.
“We’ve known historically that PRK has fewer dry eye symptoms than traditional LASIK,” she said. “We wanted to assess the incidence and severity of dry eye findings and symptoms between a new thin-flap IntraLase procedure, which we’re calling sub-Bowman’s keratomileusis, and PRK.”
All procedures were performed with an Alcon LADAR 4000 excimer laser, she said.
In early follow-up visits, from 3 days to 1 week, patients had a statistically significant greater incidence of dry eye complaints in the PRK eyes. The incidence was still higher but no longer statistically significant by 1 month through 6 months, she said.
Schirmer’s test scores and lissamine green staining results were not significantly different between the eyes at any follow-up point, she said.
At 1 month, the PRK eyes had a 5% loss in corneal sensitivity compared with a 15% loss in the SBK eyes. At 6 months, the losses were 7% and 13%, respectively, she said.
In a prior study of traditional LASIK, Dr. Stahl found that microkeratome-operated eyes had a 46% loss in corneal sensitivity at 1 month and IntraLase eyes had a 40% loss, she said.
“Overall, SBK offers the advantage of excellent visual acuity and biomechanics with a decreased healing time while providing a comparable dry eye profile to PRK,” she said.
Surgeon: Pediatric LASIK for anisometropia should gain wider acceptance
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One surgeon said that his long-term results using LASIK on anisometropic children will hopefully promote broader interest in using the technique in young patients.
Osama Ibrahim, MD, presented his data on 128 children, ranging in age from 2 to 15 years, who were followed from 6 months to 10 years.
“This technique should be popularized,” he said. “In our hands, it is the only solution to save these kids’ amblyopic eyes.”
While pediatric LASIK for anisometropic children is both effective and predictable, surgeons are still searching for the most stable methods, Dr. Ibrahim explained.
“Efficacy and predictability is the same,” he said. “Stability remains the main issue in these kids.”
Dr. Ibrahim explained that while surgeons originally overcorrected these children in anticipation of increasing myopia as they grew up, they found that the overcorrection persisted. When surgeons undercorrected, the eyes tended to continue to regress.
“Try to bring these patients to emmetropia because once they are emmetropic, they tend to maintain this emmetropia,” he said. “The eye tends to maintain this condition.”
Wavefront-guided surface ablation effective in eyes with high coma, trefoil
Wavefront-guided surface ablation is a safe and effective way to improve vision in eyes with significant coma or trefoil, one surgeon said.
David R. Hardten, MD, presented the short-term results of a retrospective study of the procedure. Dr. Hardten and colleagues looked at 121 eyes of 71 patients who had either high coma or trefoil associated with atypical topography. Mean preoperative spherical equivalent was 3.5 D with mean astigmatism of 0.7 D. Mean coma and trefoil were 0.3 µm and 0.17 µm, respectively, he said.
Surgeons used a Visx Star S4 excimer laser (AMO) to perform PRK or alcohol-assisted LASEK with a mean depth of treatment of 60 µm. No microkeratome cases were included in the study, he said.
A total of 110 cases were available for follow-up at 3 or more months postop. Mean spherical equivalent was reduced to 0.02 D with 0.3 D of astigmatism. Uncorrected visual acuity was 20/20 or better in 80% of patients and 20/40 or better in all patients, Dr. Hardten said.
Preliminary 1-year data indicated that 95% of patients were 20/25 or better, he said.
“In this group of patients where the surgeon chose PRK over LASIK because of atypical findings on the cornea, the results are good,” he said. “But they’re not as good as in LASIK in normal eyes, so these patients all received special counseling about the fact that they weren’t going to be as accurate because there was something else unusual about their eyes.”
Laser presbyopia reversal effective for near vision improvement at 2 years
Two-year results show that laser presbyopia reversal is effective for improving near vision and accommodation in presbyopic patients, according to a surgeon.
Charles E. Rassier, MD, presented the results of a prospective study of laser presbyopia reversal. He and his colleagues tracked 30 patients aged 50 to 64 years who underwent the procedure. All patients had minimal refractive error and were free of systemic and ophthalmic disease at baseline, he said.
“Laser presbyopia reversal utilizes an Erbium:YAG laser — a 20-mJ laser operating at 20-Hz frequency — to ablate scleral tissue,” Dr. Rassier said. In all patients, surgeons used the laser to create “four pairs of scleral ablations starting 0.5 mm posterior to the limbus. The ablation patterns measured approximately 4.5 mm in length and each ablation was separated by 2.5 mm,” he said.
In all cases, the sclera was ablated to a depth of 80% total thickness plus or minus 10%, he said. The final endpoint was direct observation of a “bluish choroidal hue.”
Nine patients were followed up at 2 years, he said. Uncorrected visual acuity had improved to approximately J3 from J8 at baseline, Dr. Rassier said.
“[Laser presbyopia reversal] appears to be a promising technology and hopefully reading glasses will be a thing of the past,” he said.
Refractive keratectomy with vector planning for keratoconus maintains outcomes at 10 years
 Noel A. Alpins |
Photoastigmatic refractive keratectomy with vector planning is safe and effective for reducing myopia and astigmatism in eyes with forme fruste and mild keratoconus, according to Noel A. Alpins, FRANZCO, FRCOphth, FACS, who presented the 10-year results of the procedure.
Whereas most laser eye surgery is guided by refractive astigmatism, Dr. Alpins explained, vector planning uses ocular residual astigmatism — the vectorial difference between refractive and corneal astigmatism — to calculate ablation parameters.
Treatment by refraction or wavefront alone leaves all of the ocular residual astigmatism on the cornea, Dr. Alpins said. Vector planning, however, aims to correct astigmatism equally, with 50% emphasis on reducing both topographic and manifest refractive astigmatism, instead of 100% on refractive astigmatism, he wrote in his study. The resultant treatment is more closely aligned to the principal corneal meridia, he said.
“So we’re actually halving the amount of astigmatism left on the cornea, and the nice surprise is that we did better in the refractive element as well,” Dr. Alpins said. The reduction of excess astigmatism is key for keratoconic patients, he said, as it has an irregular component and may be the cause of negative outcomes common in these patients.
Risk factor scale predicted almost 93% of post-LASIK ectasia cases
A stratified risk factor scale successfully identified almost 93% of cases that developed corneal ectasia after undergoing LASIK, a surgeon said.
J. Bradley Randleman, MD, developed the scale and validated its predictive ability in a study he presented at the meeting.
The risk factor scale assigns a value of 0 to 4 to a variety of potential ectasia risk factors, including patient age, topography, preop corneal thickness, preop refraction and residual stromal bed.
A higher combined score indicates a higher risk of developing ectasia, Dr. Randleman said.
Dr. Randleman and colleagues used the scale to retrospectively score 27 post-LASIK ectasia cases and 50 healthy post-LASIK controls. He found the scale successfully identified 92.6% of ectasia patients as high risk and 98.5% of controls as low risk, he said.
In comparison, he applied a traditional risk analysis to his cohort and identified only 66% of the ectasia patients as high risk, he said.
While the results are promising, Dr. Randleman cautioned that some ectasia cases are still unpredictable.
“Some eyes will still undoubtedly develop ectasia after surgery,” he said. “Therefore, I think it’s important for us to know and discuss with our colleagues and legal analysts that the development of postoperative ectasia does not in and of itself indicate malpractice.”
Cataract/IOLs
Surgeon: Ophthalmologists should embrace new treatment paradigm
Ophthalmologists must rise to the challenge of delivering more patient care caused by the popularity of presbyopia-correcting IOLs to stay viable in the marketplace, a surgeon said.
I. Howard Fine, MD, spoke at a symposium on the fundamentals of presbyopia-correcting IOL practices.
 I. Howard Fine |
He highlighted how patient treatment is changing due to numerous factors, including the high cost and health care expectations of patients who receive presbyopia-correcting IOLs. Presbyopia is the most common refractive error in the United States, he said. As baby boomers age and desire better vision, the field should expand even more.
“Over the past 20 years, physicians have found themselves in a market-based environment with respect to costs, that is to say, billing, hiring personnel, paying rent, but we’re in a socialized environment with respect to reimbursement,” Dr. Fine said. “This is the worst of all possibilities.”
He said the new paradigm employs high-quality, personalized, patient-based care to deal with the changing marketplace. Those factors should become the “mainstay” of ophthalmic practices, he said. Maintenance of those factors will require close monitoring of outcomes, discussing all options with patients and interactive, informed patient consent, Dr. Fine said.
Vision continues improving up to 12 months after multifocal IOL implantation
Patients bilaterally implanted with the Tecnis multifocal IOL had a significant improvement in both contrast sensitivity and visual acuity between 6 and 12 months postop, a prospective study found.
Ana F. Fonseca, MD, and colleagues compared the visual outcomes between 6 and 12 months postop for 14 eyes of seven patients implanted with the Tecnis IOL (AMO). The researchers assessed both uncorrected and best corrected distance and near visual acuities as well as binocular contrast sensitivity measured under photopic and mesopic conditions.
At 6 months follow-up, all patients had 16/20 best corrected distance visual acuity and J1 near visual acuity. At 12 months, UCVA was 12/20 and BCVA was 10/20.
Also at 12 months follow-up, all patients had J1 near visual acuity, except for one patient who could read at J2 uncorrected, Dr. Fonseca said. All patients were satisfied with their refractive results, she noted.
“The Tecnis multifocal IOL provides good refractive results in visual acuity with high results of spectacle independence,” she said. “However, it doesn’t suit every patient.”
Study: multifocal IOL offers excellent near, distance vision
The AcrySof ReSTOR multifocal IOL provides “excellent” near and distance vision and is associated with good overall patient satisfaction, despite some issues with glare and halos, according to one surgeon.
Josh Fullmer, MD, and a colleague reviewed the charts of 50 patients bilaterally implanted with the AcrySof ReSTOR IOL (Alcon). They also performed a telephone survey of 48 of these 50 patients that evaluated spectacle independence and satisfaction with the lens. Respondents were also asked about any glare or halo problems and whether such visual disturbances affected their performance of daily activities.
At 1 month follow-up, 90% of patients had achieved J1 uncorrected best distance visual acuity, 88% had 20/20 uncorrected distance vision and all patients were at least 20/30, according to the study.
The survey found that 76% of patients required no spectacle correction. Of those who did use spectacles, 83% only occasionally used reading glasses, Dr. Fullmer said. Also, only about 29% of respondents reported blurriness at intermediate distances, he added.
Anterior capsule tear a possible complication of phakic IOL implantation
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Looking for iatrogenic capsular defects before phakic IOL implantation could help avoid intraoperative capsular complications, according to a surgeon.
Harry B. Grabow, MD, discussed a case involving a 28-year-old woman whom he implanted with the ICL phakic IOL (STAAR Surgical). As he positioned the footplate of the lens, he suddenly noticed an anterior capsular tear, he said.
“My heart just stopped. I’m thinking everything. ‘Do I leave this in? No, you can’t leave it in, she would get iritis glaucoma. If I pull out the ICL, the iris comes out,’” he said. “I knew that I had to extend this around and do a rhexis, which is what I did.”
Dr. Grabow performed a clear lensectomy, implanted a three-piece silicone lens and returned the prolapsed iris to the eye. He then performed an Nd:YAG laser posterior capsulotomy.
Postoperatively, the patient achieved UCVA of 20/20 with a plano refractive spherical equivalent.
While reviewing a video recording of the surgery, Dr. Grabow said he noticed a small, white mark on the anterior capsule in the meridian of one of the laser iridotomies. That mark could have created a thinning and weakening of the anterior capsule in that location, which is where the capsular tear occurred, he said.
Dr. Grabow recommends having patients sign a consent form that states that there is a remote possibility such a complication could occur. He also recommended that surgeons be prepared to manage one should it occur.
Phaco ‘crush’ minimizes ultrasound time, energy
A phacoemulsification “crush” technique minimizes ultrasound energy and time by using high-vacuum one-handed phaco with a spatula, according to a surgeon.
Judy I. Ou, MD, and colleague reviewed data of 100 eyes treated with either the phaco crush or phaco chop technique for moderately dense cataract. Surgeons used the Series 2000 Legacy unit (Alcon) in all procedures.
The phaco crush technique is performed with the phaco tip holding the nucleus and a one-handed chop made with a spatula. Mechanical crushing is then performed using the beveled- and chiseled-ended spatula, Dr. Ou said.
In the study, the researchers found that the phaco chop technique had an effective ultrasound time of 0.6 vs. an effective ultrasound time of 0.25 for the phaco crush technique. The difference was statistically significant, she said.
“The phaco crush technique leads to 42% lower effective phaco time than phaco chop, and there’s no statistically significant difference in total operative time,” Dr. Ou said.
Study finds better night driving ability with aspheric vs. spheric IOL
Compared with a spherical IOL, patients implanted with an aspheric lens were better able to detect target objects such as pedestrians in simulated night driving conditions, a surgeon said.
Robert P. Lehmann, MD, performed a prospective, randomized, observer- and subject-masked study comparing the functional performance between the spheric AcrySof IOL (SA60AT, Alcon) and the aspheric AcrySof IQ IOL (SN60WF, Alcon).
The study included 75 patients contralaterally implanted with either lens. Functional performance was tested in 44 patients using a portable Night Driving Simulator (Vision Sciences Research Corp.). Patients monocularly viewed either rural night driving scenes with low-beam illumination or city driving scenes with street lights and low-beam illumination. Both tests were conducted under normal, fog and glare conditions, according to the study.
A safe driving response time was defined as 0.5 seconds, Dr. Lehmann said. The aspheric IOL not only met that level in rural detection, but also met warning signs in glare, fog and normal circumstances, he noted.
“The distance differences favor the aspheric IQ and resulted in clinically relevant advantages in the amount of time to react to target,” or in other words, less than half a second under virtually all the conditions tested, Dr. Lehmann said. “I think this fairly conclusively demonstrates that the aspheric design of the AcrySof IQ lens merits not only theoretical but functional real world benefits.”
Zernike promising for measurement of corneal spherical aberration
Technology that is evolving to include more aspheric options and better diagnostic software could be on the market within the year, according to a presenter.
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Jack T. Holladay, MD, evaluated the use of two methods available for measuring corneal spherical aberration to choose the best aspheric IOL for each patient. His presentation won best paper of the session in the aspheric IOL category.
His study looked at more than 300 patients, all measured with an OPD Scan (Nidek) to obtain an average corneal spherical aberration, using Zernike Z (4.0) over a 6-mm zone of +0.27 µm (range 0 µm to +0.5 µm in the normal population).
Topographic measurements were also taken with the Humphrey Atlas corneal topographer (Carl Zeiss Meditec), the Eyesys (Oculus) and Orbscan (B&L) and were imported into VOL 3D software (Sarver and Associates).
The Zernike measurement was then calculated for corneal spherical aberration over the same zone. Results from both techniques were nearly identical in each patient, with a less than 0.01 difference in the measurements.
“We all want to have this 20/15 vision. It’s absolutely perfect, so we can see the mountains and the trees and everything up close,” Dr. Holladay said. “It’s wonderful today that we’re going from spherical IOLs, and now, as we’ve done in laser surgery, we are customizing our lens to the individual patient. New technology will allow you to do that.”
Centerflex IOL associated with low capsulotomy rate at 3 years postop
The Centerflex foldable hydrophilic acrylic IOL was associated with a 5.2% rate of symptomatic posterior capsular opacification requiring Nd:YAG capsulotomy after 3 years in vivo, a retrospective study found.
Rebecca L. Ford, MD, and colleagues at Whipps Cross Hospital, London, and Harold Wood Hospital in Romford, England, reviewed the rate of Nd:YAG capsulotomies performed from 2000 to 2003 in patients implanted with the Centerflex single-piece IOL (Rayner).
Four senior surgeons at the two hospitals performed 3,325 routine cataract surgeries with Centerflex implantation. Of these, 172 required laser capsulotomies (5.2%) within the 3-year period, Dr. Ford said.
“It seems that the peak time was within 16 months of surgery,” she said.
Topical drug for early cataracts shows potential against intraocular calcification
A topical drug being investigated for treating early cataracts may also be effective for treating band keratopathy, intraocular calcification and asteroid hyalosis, a surgeon said.
Randall J. Olson, MD, discussed the results of a recent early-stage clinical trial of the drug. “I think that it will be clinically important for intraocular calcification issues — the role in clinical treatment of cataracts,” he said.
Arresting cataract formation involves the creation and removal of multilamellar bodies, which are an integral part of early cataract growth, Dr. Olson said.
“There is clear evidence that this material can remove multilamellar bodies,” he said, noting that removing the multilamellar bodies would affect the rate at which cataracts form.
A note from the editors:
To facilitate bringing news to readers rapidly, for OSN SuperSite articles and meeting wrap-up articles, OSN departs from its editorial policy and typically does not send these items out for source corrections.