Refractive surgery trends

Results of the 2009 International Society of Refractive Surgery (ISRS) survey examining refractive surgery practice patterns in the United States show total surgical volume decreased while surgeons are continuing to embrace new techniques and technology that can afford safer and more predictable outcomes, said Dr Richard Duffey.

Dr Duffey conducts this project in collaboration with David Leaming, MD. He presented findings from analyses of 134 survey responders.

"This is the 13th year of the survey, but the first year we have conducted it online," said Dr Duffey, a private practitioner in Mobile, Alabama, USA. "We e-mailed 1307 messages to US ISRS members in August, 700 surgeons opened the message, and we included data from responses received by 1 October.

After adjusting for a small decrease in ISRS membership, the total volume of laser vision correction was reduced about 15% compared with 2008. The proportion of 'high volume' surgeons, defined for the purpose of the survey as those performing at least 75 cases per month, was 12%.

For a 30-year-old patient with myopia and a refractive error of –10 D, 43% of surgeons identified a phakic IOL as their preferred surgery, while about 40% said they would do laser vision correction.

For a 45-year-old patient with +3 D of hyperopia, LASIK was clearly preferred over refractive lens exchange, 68% versus 19%, respectively. However, for a patient of this age with +5 D hyperopia, refractive lens exchange predominated, with about two-thirds of surgeons identifying it as their preferred procedure compared with only about 10% who would perform LASIK.

Monovision still ranked as the most common choice for treating presbyopia (48%) followed by modified monovision (27%), but use of presbyopia-correcting IOLs had increased. For the latter technology, highest preferences were for the AcrySof ReSTOR multifocal IOL (Alcon Laboratories) at 9%, and Crystalens accommodating IOL (Bausch + Lomb) at 6%. The Tecnis Multifocal IOL (Abbott Medical Optics), which was first approved in 2009, had a 4% presence; however, none of the respondents were using the ReZoom multifocal IOL (Abbott Medical Optics).

In 2009, 8% of respondents said they would perform bilateral refractive lens exchange at the same session and 18% would implant a phakic IOL in both eyes of a patient.

Responses to questions on technology used showed VISX was still the dominant laser platform (58%), although there was a drop-off in its use compared with 2008, while WaveLight (Alcon) was enjoying continued growth, reaching 29% in the 2009 survey.

"Wavefront-guided customized procedures continued to be in good health with 90% of the respondents indicating they perform these procedures and more than half (56%) indicating they do customized surgery in more than three-quarters of their patients," Dr Duffey said.

Representation of topography units appeared consistent with previous years - the Humphrey Atlas (Carl Zeiss Meditec), Orbscan (Bausch + Lomb), and Pentacam (Oculus) lead at 39%, 30% and 23%, respectively.

The majority of surgeons were now using a femtosecond laser for flap creation with 46% saying they used an IntraLase platform (Abbott Medical Optics) and 6% having the Femto LDV (Ziemer).

"With this shift to the femtosecond laser, it was not surprising to see that when there are no other limitations, the proportion of surgeons selecting 100 µm as their preferred flap thickness increased, reaching 49% in the 2009 survey," Dr Duffey said. "This was accompanied by an increase in preferred minimal residual stromal bed thickness. This year, 54% of surgeons recommend 275 µm or greater."

Almost two-thirds of surgeons felt 480 µm was an adequate minimum central corneal pachymetry measurement for LASIK candidates, given all other parameters being normal, while 36% believed the cut-off should be 500 µm or higher. The majority of surgeons, 57%, said they do not routinely measure flap thickness, although that proportion has been declining slowly.

"With use of thinner flaps and thicker residual stromal beds, new cases of post-LASIK ectasia are thankfully on the decline," Dr Duffey said.

Complete results from 13 years of the survey are available at http://www.duffey-laser.com/