Diabetic retinopathy (DR) is a leading cause of vision loss in working-age Americans. Capillary damage from hyperglycemia causes vision loss through downstream effects, such as retinal ischemia, edema, and neovascularization (NV). Proper screening and timely treatment with laser photocoagulation and anti-vascular endothelial growth factor (VEGF) injections can minimize morbidity. In the last decade, clinicians have been able to use objective structural data from optical coherence tomography (OCT) to guide the treatment of diabetic macular edema. Other aspects of care, however, still largely depend on subjective interpretation of clinical features and fluorescein angiography (FA) to determine the disease severity and treatment threshold. The recently developed OCT angiography (OCTA) provides dye-less, injection-free, three-dimensional images of the retinal and choroidal circulation with high capillary contrast. Not only is it safer, faster, and less expensive than conventional dye-based angiography, OCTA provides the potential of giving clinicians objective tools for determining severity of disease by detecting and quantifying NV and non-perfusion.

Participant-Related Inclusion Criteria:

I. All Diabetics (Groups A, B, C)

• Type 1 diabetes of at least 5 years duration or
• Type 2 diabetes of any duration II. Group B
• Able to return for follow-up over 3 years

Participant-Related Exclusion Criteria:

I. Group B

• Significant medical condition that would make long-term follow-up difficult II. Controls (Group D)
• Any medical problems associated with retinal vascular abnormalities (i.e., hypertension, systemic vasculitis, carotid insufficiency, etc.)

Eye-Related Inclusion Criteria:

I. Group A:

• Presence of active neovascularization, with or without prior treatment
• Presence of involuted fibrovascular proliferans

II. Group B:

• NPDR of any severity as defined by the International Clinical Diabetic Retinopathy Severity Scale

III. Groups C & D:

• No evidence of diabetic retinopathy

IV. Group ME:

• Presence of center-involving macular edema requiring treatment

Eye-Related Exclusion Criteria: (Applies to study eye only. May be present in non-study eye.)

• Visual acuity worse than 20/200
• Inability to maintain stable fixation for OCT imaging
• History of major eye surgery (vitrectomy, cataract surgery, scleral buckle, other intraocular surgery, etc.) within 90 days of enrollment
• History of another eye disease or condition that may alter retinal perfusion, permeability, or retinal anatomy
• Substantial media opacity (cataract, corneal scar, vitreous hemorrhage) that may interfere with study imaging

Adults age 18 or older with either healthy eyes or diabetic retinopathy