1. JAMA Ophthalmology Journal Club Slides: OCT Angiography in Type 2 Diabetes and Diabetic Retinopathy
Ting DSW, Tan GSW, Agrawal R, et al. Optical coherence tomography angiography in type 2 diabetes and diabetic retinopathy. JAMA Ophthalmol. Published online February 16, doi: /jamaophthalmol

2. Introduction Importance: Objective:
Optical coherence tomographic angiography (OCT-A) is able to visualize retinal microvasculature without the need for injection of fluorescein contrast dye.
Previous studies reporting on OCT-A have been small and none have evaluated the effect of systemic metabolic and vascular risk factors on the retinal microvascular density and branching complexity measured via OCT-A.
This prospective study describes the application of OCT-A to study a cohort of patients with diabetes and diabetic retinopathy (DR) and examines a variety of measures with metabolic and systemic vascular risk factors. It documents functional and structural changes in the retinal microvasculature associated with severity of DR and risk factors and suggests that OCT-A is a new, time-efficient, noninvasive tool to quantify the retinal capillary microvasculature to study diabetes, its microvascular and macrovascular complications, and potentially its outcomes.
Objective:
To evaluate the retinal microvasculature using OCT-A in patients with type 2 diabetes as well as the association of OCT-A characteristics with DR and systemic risk factors.

3. Methods
A prospective, observational study was conducted from January 1 to June 30, 2016, at medical retina clinics at the Singapore National Eye Center among 50 patients with type 2 diabetes with and without DR (n = 100 eyes).
The retinal microvasculature was examined with swept-source OCT-A and a semiautomated software to measure the capillary density index (CDI) and fractal dimension (FD) at the superficial vascular plexus (SVP) and deep retinal vascular plexus (DVP).
Data were collected on histories of patients’ glycated hemoglobin A1c, hypertension, hyperlipidemia, smoking, and renal impairment.
Main outcomes and measures were the CDI and FD at the SVP and DVP for each severity level of DR and the association of systemic risk factors vs the CDI and FD.

4. Results
Individual Quadrant and Global Capillary Density Index at Superficial and Deep Vascular Plexuses

5. Results
Fractal Dimension at the Superficial Vascular Plexus and Deep Vascular Plexus

6. Retina of a Patient With Severe Nonproliferative Diabetic Retinopathy
Results
Retina of a Patient With Severe Nonproliferative Diabetic Retinopathy
Binarized?

7. Results
Nonsegmented and Corresponding Binarized Optical Coherence Tomographic Angiography Images
Changed to binarized – if binarized is a word (also on previous slide)

8. Results
Multivariate Analysis of Risk Factors for Low Capillary Density Index (Lower Quartile) and High Fractal Dimension (Upper Quartile)
binarised

9. Comment
OCT-A is a new noninvasive tool to quantify the retinal capillary microvasculature to study diabetes and its complications, including complications not related to the eye.
OCT-A the potential to be used in larger epidemiologic and clinical studies, including interventional trials, to directly visualize the microvasculature that was previously not accessible in a noninvasive manner.

10. Conflict of Interest Disclosures
Contact Information
If you have questions, please contact the corresponding author:
Tien Yin Wong, MD, PhD, Vitreo-retinal Department, Singapore National Eye Center, 11 Third Hospital Ave, Singapore
Funding/Support
This study was supported by Singapore Health Service (SingHealth) Duke National University Singapore Medical School Academic Clinical Program Talent Development grant R277/83/2015 (ACP-2-1).
Conflict of Interest Disclosures
None were reported.