OCT technology has become prevalent in all areas of ophthalmic care over the past decade, with technological improvements allowing faster acquisition times and higher fidelity images. The latest breakthrough is OCT angiography (often abbreviated as OCTA). While still in its infancy, it is already being heralded as revolutionary.
As opposed to static images obtained with traditional OCT devices, OCT angiography is performed with multiple images, typically in the same location, to allow imaging of the retinal and choroidal vasculature. Real time tracking technology such as Zeiss’s FastTrac minimizes any artifact and ensures accurate readings.
While OCT angiography does not provide all the detail of traditional fluorescein angiograms, in many ways it provides more clinical information. To begin, blood flow and areas of choroidal neovascularization can be measured, and this has significant potential for evaluating success of therapy. Furthermore, the peripapillary capillary network may be better visualized.
There also may be potential for glaucoma diagnosis, as optic nerve perfusion has been shown to correlate with the disease. With OCT angiography all of this information can be obtained in a non-invasive method, and as opposed to a traditional fluorescein angiogram, it can be acquired in a manner of seconds without the need for a contrast medium.
Today in the United States, there are two available approved OCT angiography systems, AngioPlex from Zeiss and AngioVue from Optovue.
AngioPlex is a software algorithm for the CIRRUS 5000 HD-OCT platform that uses full depth color encoded images to clearly illustrate vascular pathology. In diabetic retinopathy it can show microaneurysms and areas of ischemia. In age related macular degeneration it can reveal the presence of a choroidal neovascular membrane. And in vascular occlusions it can show the location of the occlusion and the extent of the ischemia.
AngioVue is a dual mode imaging system capable of capturing traditional OCT images as well as OCT angiography to help clinicians assess both the structure and the function of ocular microvasculature. The system is designed to provide a non-invasive way for clinicians to document and track the progression of patients’ conditions.
Additionally, Heidelberg Engineering is currently developing a similar technology to add OCT angiography capabilities to the SPECTRALIS platform.
Of course, for some data, fluorescein angiogram will still have to be performed. However, it is very reasonable that patients may only require one fluorescein angiogram combined with OCT angiography at their initial visit for diagnostic purposes, followed by only OCT angiography at subsequent encounters.
While there is no current CPT code approved by CMS and compensation will be the same as a regular OCT, reimbursement continues to decrease every year. Given the time saved over FA and patient convenience factor, OCT angiography will still be financially worthwhile for busy practices.
There is no doubt that as the technology continues to evolve and data acquisition becomes even more robust, this will completely replace fluorescein angiography for the majority of posterior segment disease.