Comparison of Phase-variance Optical Coherence Tomography and Fluorescein Angiography in Retinovascular Imaging (PVOCT)

• Measurement of to be determined physical characteristics of retinovascular structures seen on phase variance optical coherence tomography (PV-OCT) and fluorescein angiography(FA). [ Time Frame: On the day in which a patient receives PV-OCT and FA imaging, estimated to take 2 hours. ] [ Designated as safety issue: No ]
  Masked examiners (retina specialists) will evaluate and grade coded PV-OCT and FA images for the presence and features of various retinovascular abnormalities (e.g., choroidal neovascular membranes, microaneurysms, venous dilation, etc.). Metrics to determined and may include: size, depth, area, volume, and relative position. Each subject's graded PV-OCT images will be compared to their graded FA images.
  
  

• Changes over time in the to be determined measured physical characteristics of retinovascular structures seen on PV-OCT and FA. [ Time Frame: Up to 12 months after enrollment. ] [ Designated as safety issue: No ]
  Each time a subject is determined to require OCT imaging as part of their normal clinical evaluation over the duration of the study, a PV-OCT scan will also be performed. Measured to be determined physical characteristics of these scans will be compared to measurements obtained from prior PV-OCT images in order to assess changes over time.
  
  

Fluorescein angiography (FA) has long been the gold standard for vascular imaging of the retina and choroid. It is a test that involves the intravenous injection of fluorescein dye, followed by imaging of the dye's passage through the blood vessels inside the eye. It is commonly used to diagnose many forms of retinovascular disease, as well as to assess the retina's response to various therapeutic interventions. While FA is a relatively safe diagnostic test, it carries the risk of both minor and major side effects. These include nausea and vomiting, yellowing of the skin and urine, vascular extravasation with skin eruption and necrosis, vasovagal reactions, myocardial infarction, respiratory failure, anaphylaxis, cardiopulmonary arrest, and death. Additionally, the test is time-consuming, technically difficult to perform, and requires patients to undergo the discomfort associated with intravenous access. Despite these drawbacks, FA is still commonly used in clinical practice, as there are no existing alternative tests with the ability to provide comparable detail of the retinal and choroidal vasculature.

Phase-variance optical coherence tomography is a novel, noninvasive, software-based technology capable of generating angiographic images from the data gathered by standard OCT scans. Preliminary research suggests it can produce high-definition representations of the retinal and choroidal vasculature which may be more detailed than the images produced by FA.