Application in clinical care
In routine practice, the focus of follow-up by retina specialists in patients with diabetes includes evaluation for worsening of diabetic retinopathy and for the development of macular edema, macular ischemia, and neovascularization. In addition, widefield imaging may be used to identify nonperfusion in the periphery.
Dr. Waheed said OCTA enables early visualization of diabetic vascular changes in the eye and their quantification, thereby allowing better follow-up over time. Its ability to characterize the deep capillary plexus also has ramifications for patient care since changes in the deep vasculature have been shown to be associated with the evolution of diabetic macular edema (DME).
“Increasing development of microaneurysms in the deep capillary plexus has been shown to be predictive of DME development and potentially of recurrence after response to anti-VEGF treatment for DME,” Dr. Waheed said.
In addition, OCTA allows precise correlation of structure to vasculature that can help with understanding clinical status. Discussing a patient being treated for DME, Dr. Waheed noted that while the macular edema resolved with anti-VEGF therapy and the patient’s vision improved, visual acuity plateaued at 20/40.
“OCTA showed the presence of ischemia that provided an explanation for the vision outcome that could not be determined with the structural OCT alone,” Dr. Waheed said.
In addition, OCTA allows precise monitoring of proliferative diabetic retinopathy as it can be used to map out the size of the neovascular network. However, OCTA has a limited field of view.
“The central images with OCTA are of much higher resolution than those obtained with fluorescein angiography,” Dr. Waheed said. “OCTA does not allow for evaluation of peripheral areas of nonperfusion as can fluorescein angiography.”