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Vitrectomy maintains significant role in management of DME
The procedure can help improve visual acuity in eyes that are refractory to treatment.
The availability of more treatment choices is one reason why the management of chronic diabetic macular edema has become a less straightforward treatment paradigm than it once was. As part of the ever-expanding list of options, vitrectomy should be considered highly in some situations, a specialist said.
“Management of chronic DME is probably the biggest day-to-day challenge for a retina specialist when trying to figure out the next treatment move,” Tarek S. Hassan, MD, said at Retina 2013. “I think some of this is for good reasons. We have more choices for treatment. We also understand the disease better. We can see the diabetic edema better. And then there is the bad reason that, in some eyes, the disease is such that there’s no help and the macular edema becomes refractory.”
Refractory cases
According to Hassan, a key area that needs to be assessed with DME is the potential for posterior hyaloidal traction, which is relieved with vitrectomy.
Vitrectomy can allow for visual acuity improvement in some eyes that are refractory to treatment, he said.
Tarek S. Hassan
“Those who flatly say vitrectomy does not work ignore critical data from many case series from many centers over many years,” Hassan said. “I would say physicians are overly reliant on intravitreal injections and/or laser treatment for refractory DME and underappreciate other potential alternatives.”
Hassan said physicians may not consider all aspects of the complex pathophysiology of DME and thus not look for the appropriate place for vitrectomy in their treatment regimen.
Citing numerous studies from 1996 to 2005, Hassan said data have shown that performing vitrectomy on both visibly taut and not visibly taut posterior hyaloidal traction has produced visual acuity improvement of two or more lines and has resolved macular edema that occurred in more than half to nearly all study participants. These were trials that were done largely before the advent of intravitreal steroid and anti-VEGF injections, he said.
Numerous clinical trials have shown vitrectomy for DME works best in eyes with a short duration of DME, little-to-no macular ischemia, mild or no preoperative laser treatment, no foveal hard exudates, better preoperative visual acuity and an obviously taut posterior hyaloid or epiretinal membrane, he said.
“Before injections, we were trying definitive procedures like vitrectomy earlier in the course of chronic DME than presently,” Hassan said.
Variables in vitrectomy
Hassan said conflicting data exist on the success of vitrectomy, but physicians should be skeptical of uncontrolled, nonrandomized science. Physicians should also be skeptical of large clinical trials that do not control for the many variables that exist among eyes with chronic DME.
“If you go to the literature on vitrectomy for DME, some will say this procedure works and some will say it does not,” he said.
To better assess the benefits of vitrectomy, Hassan said physicians should evaluate several factors within clinical studies, including patient characteristics, the study’s definition of “traction,” the amount of macular ischemia, retinal pigment epithelial atrophy and choroidal ischemia, and the definition of surgical parameters and techniques used.
“The problem is, there are so many variables that, as the studies are written, they can rarely ever be compared to one another to further assess data,” he said.
According to Hassan, physicians should consider the relative contribution of each part of the vitrectomy procedure, from the vitrectomy and membrane peeling to the panretinal photocoagulation and possible intravitreal steroid injection, and determine the proper place for vitrectomy in a patient’s treatment regimen.
“DME is complex, especially when refractory, and it cannot be approached by simply considering one treatment directed at one mechanism,” Hassan said. “Vitrectomy should have a significant role because it works, but you have to look for and define the role relative to other treatments.” – by Ashley Biro