ASCRS members adopting latest refractive advances, survey finds

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. However, for a patient in the same age group with 5 D of hyperopia, 51% of respondents would do a refractive lens exchange, and only 9% would do LASIK.

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 femtosecond laser (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.

The following are other highlights of special presentations from the ASCRS. All of these items appeared first as daily coverage of the meeting on OSNSuperSite.com and PCONSuperSite.com.

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 the 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.

Pediatric LASIK for anisometropia should gain wider acceptance

One surgeon said he hopes that his long-term results using LASIK on anisometropic children will 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.

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 (Advanced Medical Optics) 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 quite 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 (LAPR) 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 50 to 64 years old 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, he said.

“LAPR appears to be a promising technology, and it is hoped that reading glasses will be a thing of the past,” Dr. Rassier said.

Refractive keratectomy with vector planning for keratoconus maintains outcomes at 10 years

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.

In the study, Dr. Alpins and George Stamatelatos, BScOptom, retrospectively tracked 45 patients with mild or forme fruste keratoconus who underwent the procedure. At baseline, all patients had a best corrected visual acuity of 20/40 or better, no signs of keratoconus at the slit lamp, mean keratometry less that 50 D and corneal and refractive stability for at least 2 years.

Preop mean refractive astigmatism was –1.39 D, and corneal astigmatism was 1.7 D. Mean ocular residual astigmatism was 1.34 D. Treatments were targeted to correct about 36% of corneal astigmatism and 64% of manifest cylinder. Surgeons used the STAR S1 or S2 excimer laser (AMO) on all patients.

At 12 months postop, refractive and corneal astigmatism had improved to -0.43 D and 1.02 D, respectively. UCVA was 20/20 or better in 56% of eyes and 20/40 or better in all eyes. BCVA was 20/20 or better in 89% of eyes and 20/30 or better in all eyes. Overall, 16 eyes gained BCVA and seven eyes lost BCVA, Dr. Alpins said.

A total of 32 eyes had 5 years of follow-up and nine eyes had 10 years of follow-up. At last follow-up, the group’s spherical and refractive outcomes were stable and there were no cases of keratoconus progression or ectasia, Dr. Alpins said. This may be the result of careful patient selection, he said.

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.

He and his 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 very 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.”

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 VA and J1 near VA. At 12 months, UCVA was 12/20 and BCVA was 10/20.

Also at 12 months follow-up, all patients had J1 near VA, 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. We have to be careful [about] whom we are going to implant … and it might require some cortical adaptation, which could explain the improvement in vision quality from the 6-month to 12-month follow-up.”

Study: ReStor lens 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.

Overall, 46 of the 48 survey respondents reported being satisfied with the lens. Only one patient indicated dissatisfaction with the lens and stated that he or she would not have the lens implanted again. However, this patient would recommend the lens to friends, Dr. Fullmer said.

“The ReStor lens provides excellent near and distance acuity and adequate spectacle freedom; the lens has significant glare but, overall, patient satisfaction was very good,” he said.

Study finds better night driving with aspheric 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.”     

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