Evaluating Signs of Microangiopathy Secondary to Diabetes in Different Areas of the Retina with Swept Source OCTA.

Purpose: The purpose of this study was to compare perfusion parameters of the parafovea with scans outside the parafovea to find an area most susceptible to changes secondary to diabetic retinopathy (DR). Methods: Patients with different DR severity levels as well as controls were included in this cross-sectional clinical trial. Seven standardized 3 × 3 mm areas were recorded with Swept Source Optical Coherence Tomography Angiography: one centered on the fovea, three were temporal to the fovea, and three nasally to the optic disc. The capillary perfusion density (PD) of the superficial capillary complex (SCC) and deep capillary complex (DCC) as well as the fractal dimension (FD) were generated. Statistical analyses were done with R software. Results: One hundred ninety-two eyes (33 controls, 51 no-DR, 41 mild DR, 37 moderate/severe DR, and 30 proliferative DR), of which 105 patients with diabetes and 25 healthy controls were included (59 ± 15 years; 62 women). Mean PD of the DCC was significantly less in patients without DR (parafovea = 0.48 ± 0.03; temporal = 0.48 ± 0.02; and nasal = 0.48 ± 0.03) compared to controls (parafovea = 0.49 ± 0.02; temporal = 0.50 ± 0.02; and nasal = 0.50 ± 0.03). With increasing DR severity, PD and FD of the SCC and DCC further decreased. Conclusions: Capillary perfusion of the retina is affected early by diabetes. PD of the DCC was significantly reduced in patients with diabetes who did not have any clinical signs of DR. The capillary network outside the parafovea was more susceptible to capillary perfusion deficits compared to the capillaries close to the fovea. Trial Registration: clinicaltrial.gov, NCT03765112, https://clinicaltrials.gov/ct2/show/NCT03765112?term=NCT03765112&rank=1.

Imaging of Ocular Angle Structures with Fourier Domain Optical Coherence Tomography.

BACKGROUND: Imaging of the Schlemm's Canal is complicated by the small physiological size and the location several hundred microns beneath the sclera. Noninvasive imaging of Schlemm's canal and Trabecular Meshwork (TM) in vivo with Fourier Domain Optical Coherence Tomography (FD OCT) can provide clinicians with a powerful tool to visualize ocular angular structures crucial for glaucoma management. PURPOSE: To investigate the appearance of Schlemm's canal and TM on FD OCT images. METHODS: FD OCT images of the Schlemm's canal and TM were obtained with three different wavelengths using prototype FD OCT systems in a normal volunteer. FD OCT images using the 1310 nm wavelength prototype were obtained in three representative cases of glaucoma surgery performed on angle structures. RESULTS: The longer imaging depth and deeper tissue penetration of the 1310 nm system provided the clearest image of the TM and Schlemm's canal in the normal patient. In case 1, images pre- and post-trabectome surgery clearly showed the location and appearance of TM. In case 2, images post-canaloplasty surgery showed the location and appearance of Schlemm's canal. In case 3, images pre- and post-trabeculotomy surgery further confirms the appearance and location of the Schlemm's canal and TM. CONCLUSION: Operating wavelength of the FD OCT system and exact location of the scan across different meridians minimally affects the appearance of the ocular anatomy. The postoperative images of three angle glaucoma surgeries confirmed the location of Schlemm's canal and TM. How to cite this article: Asrani S, Young M, Xu J, Sarunic MV. Imaging of Ocular Angle Structures with Fourier Domain Optical Coherence Tomography. J Current Glau Prac 2013;7(2):85-87.