Criticized laser study resurfaces in scope battles

April 28, 2017
Commentary: Politicized study utilized data inappropriately.

Amidst states' current legislative scope battles, a contentious ophthalmology study muddies the debate waters considering the research's ambiguous interpretation and downright validity.

Published in the October 2016 JAMA Ophthalmology, a study titled, "Comparison of Outcomes of Laser Trabeculoplasty Performed by doctors of optometry vs Ophthalmologists in Oklahoma," claims doctor of optometry-administered laser trabeculoplasties (LTPs) result in a greater risk of repeated sessions as compared to ophthalmologists, but does not provide the context that makes such findings immaterial.

Although purportedly analyzing LTP outcomes among Oklahoma's eye doctors for repeated sessions, the study instead measured utilization rates, finding doctor of optometry-treated eyes were more likely to require a follow-up LTP session as compared to an ophthalmologist. The study infers that this is an assessment of quality, even concluding: "Health policy makers should be cautious about approving laser privileges for doctors of optometry in other states until the reasons for these differences are better understood."

However, the reasons for doing LTP in repeat sessions are well-known and have nothing to do with inferior quality. Providing commentary at the request of JAMA Ophthalmology, Murray Fingeret, O.D., a glaucoma expert, contends the study was misleading not only for purporting to present outcomes—when only reporting procedure utilization rates—but also for not explaining that performing LTP in split sessions is an acceptable method.  

"Regarding this lack of information, did the authors consider the American Academy of Ophthalmology Primary Open Angle Glaucoma Preferred Practice Pattern statement that 'treating 180 degrees reduces the incidence and magnitude of post-operative IOP elevation compared with 360-degree treatment?" Dr. Fingeret wrote in his commentary. 

This distinction between 180 degrees and 360 degrees is critical. At the time of the study, the doctors of optometry trained and certified to perform LTP adhered to the above recommendation that treating 180 degrees in the first session was preferred to prevent intraocular pressure (IOP) spikes. Furthermore, the numbers of patients receiving a second session are not considered additional treatment, but rather completion of the procedure. 

"When SLT (selective LTP) was first introduced, it was understood that you can get the desired reduction in the eye pressure with only half the eye being treated, and fewer complications were seen," Dr. Fingeret says. "This is a perfectly reasonable method, and the American Academy of Ophthalmology's own practice guidelines discuss this method." 

In the years since the study period (2008-2013), the full 360-degree treatment has become more common, but the 180-degree treatment is still an acceptable albeit conservative technique, Dr. Fingeret says. There is nothing in the study to suggest any difference in the quality of care provided by a doctor of optometry versus an ophthalmologist, and the study may be flawed in not accounting for other procedures that ophthalmologists might have done in place of a repeat LTP. 

AOA, affiliates counter misleading narratives

Since the study's original presentation at the 2016 American Glaucoma Society Annual Meeting, AOA and affiliates have encountered the flawed findings rolled out during state scope battles as "evidence" against allowing doctors' of optometry laser privileges. Unfortunately, the narrative is often recycled without knowing the perspective, and that's why the AOA developed a rebuttal to the misleading data.

In addition to faulting the study for presenting utilization data as functional outcomes, the AOA also flagged the study size as being far too small—only six doctors of optometry nationwide performed this procedure at least 10 times for Medicare patients in 2013 (averaging only 1.78 procedures per patient). 

Furthermore, Medicare reimbursed 14 physicians nationwide in 2013 for 3 or more SLT treatments per patient, and only one was a doctor of optometry. This 2013 Medicare reimbursement data also showed that ophthalmologists were far more likely to perform 3 or more services, including an ophthalmologist who authored the study. 

It's for these reasons that the AOA concluded the study was a thinly veiled attempt to suppress increased optometric medical care in a treatment area where ophthalmologists presently enjoy no competition. 

"This study was an attempt to discredit SLT as being done by doctors of optometry in Oklahoma, and after 19 years of Oklahoma optometrists doing LTP, this was their best shot and it wasn't done all that well," Dr. Fingeret says. "There's no evidence that optometrists did anything inappropriate or that repeating SLT is an unreasonable technique. 

"If anything, this study shows that optometry is conservative as a profession and does everything to prevent any side effects or complications."

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