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ASCRS survey: U.S. surgeons favor femtosecond arcuate incisions for astigmatism management
In addition, efficacy ratio and patient satisfaction, not just visual acuity, should be used to assess refractive success, specialist says.
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A majority of U.S. physicians participating in the 2013 American Society of Cataract and Refractive Surgery Clinical Survey preferred femtosecond laser arcuate incisions over conventional cataract surgery in managing astigmatism.
In addition, responding physicians said they would accept fairly high levels of residual pseudophakic error after multifocal IOL implantation and high levels of rotational error in toric IOL patients.
At the ASCRS annual meeting in Boston, John A. Vukich, MD, presented astigmatism results, and Jason P. Brinton, MD, OSN Refractive Surgery Board Member, discussed findings on the assessment of refractive success. Survey results were released in November 2013.
“The survey is a comprehensive tool that the ASCRS has developed in order to get a better understanding of the membership’s current practice patterns as well as their trends in use. It is also being used as a guide to help establish the educational objectives for the year,” Vukich said.
Jason P. Brinton
John A. Vukich
A total of 1,041 ASCRS members responded to the survey, which replaced the Leaming survey as the primary instrument for gauging clinical opinions and practice patterns.
Astigmatism findings
Vukich discussed four key areas of astigmatism: femtosecond vs. manual arcuate incisions, acceptable residual cylinder levels with multifocal IOLs, toric IOLs and astigmatism management.
Overall, 56.7% of respondents said femtosecond laser arcuate incisions may provide a significant clinical benefit vs. conventional cataract surgery; the breakdown was 69.5% in the U.S. and 42.8% outside the U.S.
The average level of acceptable postoperative cylinder error after multifocal IOL implantation was 0.71 D; 45% of respondents said postoperative cylinder of 0.75 D or more was acceptable.
“In fact, what we’re really seeing is that visual quality, at least from a patient’s perception and patient satisfaction standpoint, seems to be influenced at a much lower level, almost half that, at about 0.38 D, the point at which patients can perceive a difference in the visual quality and will, in fact, start to notice a degradation of quality of vision,” Vukich said. “We’re somewhat at odds between what the patients can perceive and what physicians are willing to address. I think we need to reconsider what we are willing to leave behind.”
Among respondents, 38.9% of U.S. members and 11.5% of non-U.S. members said they would perform limbal relaxing incisions or astigmatic keratectomy to treat significant residual cylinder in multifocal IOL patients.
“I think that’s an interesting disparity,” Vukich said. “I think part of that is reflective of some of the technologies that are available outside the U.S. Very specifically, multifocal toric implants are available outside the U.S.”
In addition, 51.9% of U.S. members and 68.1% of non-U.S. members said they would perform laser refractive surgery to treat significant residual cylinder.
Results showed that 15% of cataract procedures in the U.S. and 23% outside the U.S. involved toric IOLs.
“I think there is perhaps maybe a little greater recognition of the need to correct astigmatism [outside the U.S.],” Vukich said.
Respondents were divided about evenly on flipping the axis (46.3%) or aiming for the lowest amount of residual astigmatism without flipping the axis (53.7%) when deciding on toric IOL cylinder correction.
Gauging refractive success
For 58.2% of U.S. respondents, the 20/20 rate equated with refractive success, Brinton said, but surgeons should also use other metrics, including efficacy ratio and patient satisfaction.
“Some of us aren’t measuring beyond 20/20,” Brinton said. “As we increasingly achieve 20/16 and 20/12.5 UCVA following refractive surgery, we need to be aiming for and measuring for these higher targets. Visual acuity is an important piece of the puzzle but only one piece of it.”
Survey results also showed that 24.3% of U.S. respondents and 15.9% of non-U.S. respondents had no standardized method of assessing refractive outcomes.
A small percentage of U.S. respondents (9.5%) used an efficacy ratio comparing postoperative uncorrected visual acuity with preoperative best corrected visual acuity, Brinton said. The rate among non-U.S. respondents was 13.6%.
The efficacy ratio for a patient with preoperative BCVA and postoperative UCVA of 20/20 is 1.0. The ratio for a patient with preoperative BCVA of 20/20 and postoperative UCVA of 20/16 is 1.25. The ratio for a patient with preoperative BCVA of 20/20 and postoperative UCVA of 20/12.5 is 1.60, Brinton said.
“Essentially, what we’re saying is that this ratio needs to be greater than or equal to 1 to consider the refractive procedure successful. We cannot afford to send out patients who are not seeing as well or better after surgery without correction than they could see before surgery with correction. Where yesterday’s patients sought refractive surgery to be free of contacts and glasses, today’s patients are increasingly choosing refractive surgery to achieve a level of visual function and performance unattainable with glasses and contact lenses,” he said.
Brinton said data from Steven C. Schallhorn, MD, showed an increase in patient satisfaction scores correlating with increasing postop UCVA. Patient satisfaction on a scale of 0 (fairly satisfied) to 1 (very satisfied) was 0.36 at 20/25 or worse, 0.45 at 20/25, 0.70 at 20/20, 0.81 at 20/16 and 0.87 at 20/12.5.
“It’s not hard to imagine that as UCVA progresses from 20/30 to 20/25 to 20/20, we observe a concomitant increase in patient satisfaction. What is quite telling, however, is that this trend continues with each step beyond 20/20,” Brinton said.
U.S. respondents said they believed that, on average, 29% of their patients had significantly increased dry eye after LASIK.
“Our data show this is no longer the cases, at least with modern femtosecond laser thin-flap LASIK,” Brinton said. “Patients without dry eye preoperatively had no difference in their dry eye scores at 3 months. In fact, a recent study showed a significant decrease in patient-reported dry eye symptoms at 6 months following LASIK when compared to preoperative levels.” – by Matt Hasson