Is iOCT the next paradigm shift for vitreoretinal surgery?
Take-home: Evidence is accumulating documenting that intraoperative OCT improves surgeon decision-making and outcomes of patients undergoing vitreoretinal procedures.
Reviewed by Justis P. Ehlers, MD
Take-home: Evidence is accumulating documenting that intraoperative OCT improves surgeon decision-making and outcomes of patients undergoing vitreoretinal procedures.
Justis P. Ehlers, MDCleveland-Intraoperative ocular coherence tomography (iOCT) is a useful asset when performing macular surgery and other vitreoretinal procedures. Considering the advantages it provides, iOCT may be the next paradigm shift in vitreoretinal surgery according to Justis P. Ehlers, MD.
“The evidence is here and the images are clear,” said Dr. Ehlers, the Norman C. and Donna L. Harbert Endowed Chair of Ophthalmic Research and co-director of iOCT research at the Ophthalmic Imaging Center, Cole Eye Institute, Cleveland Clinic, Cleveland.
“Show patients their OCT image, then ask if they prefer OCT-assisted surgery, and they will say, ‘yes,’ ” Dr. Ehlers said. “Then ask yourself: ‘Do I want to know exactly what I just did, and do I want objective, immediate feedback on the completion of my surgical objectives.’ My answers to those questions are ‘yes,’ and I imagine they are for other retina specialists.”
Dr. Ehlers observed that for retina specialists today, OCT drives diagnosis, therapeutic decision making, and disease surveillance more than any other imaging modality. The shift is based on studies showing OCT is superior to the clinician’s exam for visualizing various pathologies and anatomic configurations.
“What has transformed the clinic is now transforming what we do in our operating rooms,” Dr. Ehlers said. “In short, iOCT gives immediate feedback on the completion of surgical objectives and facilitates visualization of translucent tissue and membranes.”
Dr. Ehlers points out that the technology is here to stay-now with three systems having FDA clearance.
Supported by data
Evidence supporting the utility of iOCT as a tool for facilitating vitreoretinal surgery is available from more than 40 articles published in the peer-reviewed literature. Dr. Ehlers reviewed results from the two largest prospective trials-“Prospective Intraoperative and perioperative Ophthalmic imaging with optical coherencE TomogRaphy(PIONEER)” and “Determination of feasibility of Intraoperative Spectral domain microscope combined/integrated OCT Visualization during En face Retinal and ophthalmic surgery (DISCOVER)”-that were conducted at the Cleveland Clinic.
Figure A: Intraoperative OCT immediately prior to peeling epiretinal membrane (red arrow). (Figure courtesy of Justis P. Ehlers, MD)
In PIONEER, which included more than 750 eyes at final enrollment, iOCT altered surgical decision making in about 15% of membrane-peeling procedures. Data from PIONEER also indicate that use of iOCT improved outcomes.
“In PIONEER, the rate of epiretinal membrane recurrence was < 1% when using image-assisted surgery without mandated ILM peeling,” Dr. Ehlers said. “In contrast, the rate reported in the literature ranges from 5% to 15%.
“So, the evidence shows vitreoretinal surgeons performing membrane peeling can fix things the first time in 99% of cases using OCT-guided surgery versus in only 85% to 95% of cases without it,” he added.
The DISCOVER study has data for more than 350 eyes at 18 months, and it similarly showed that in 16% of eyes where surgeons thought they were done at the end of the case, iOCT revealed there was residual membrane requiring peeling.
Figure B: Intraoperative OCT immediately following membrane peeling that confirms excellent clearance of the foveal area (yellow arrow) with minimal residual membrane near the optic nerve (orange arrow). (Figure courtesy of Justis P. Ehlers, MD)
Conversely, in 20% of cases, surgeons thought there was a need for additional peeling, but iOCT showed the surgical objectives had already been achieved, reducing the need for additional surgical manipulation.
“In two-thirds of cases, iOCT provided valuable feedback in terms of identifying the membrane edge, presence of a lamellar versus full thickness hole after peeling, and confirming peel completion,” Dr. Ehlers explained. “In addition, in more than one-third of cases, iOCT changed the surgical procedure, either aborting the need for indocyanine green staining, limiting unnecessary further surgery or peeling, and identifying full-thickness macular holes.”
As much as vitreoretinal surgeons would like to believe they see everything, they don’t, Dr. Ehlers concluded. As good as surgical outcomes are, they can be better, and iOCT may be part of the paradigm that can improve outcomes.”
Justis P. Ehlers, MD
This article is based on a presentation given by Dr. Ehlers at Retina Subspecialty Day during the 2015 meeting of the American Academy of Ophthalmology. Dr. Ehlers is a consultant to Alcon Laboratories, Bioptigen, Carl Zeiss Meditec, and Leica. Dr. Ehlers also has intellectual property licensed to Bioptigen, Leica, and Synergetics.
