COMPARING FUNDUS FLUORESCEIN ANGIOGRAPHY AND SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN THE EVALUATION OF DIABETIC MACULAR PERFUSION.

PURPOSE: To compare fundus fluorescein angiography (FFA) and swept-source optical coherence tomography angiography (SS-OCTA) in the evaluation of macular perfusion in diabetic patients. METHODS: Forty-one eyes (21 diabetic patients) seen at Moorfields Eye Hospital (London) over a 1-month interval underwent color fundus photography, FFA, and SS-OCTA imaging of the capillary superficial plexus using 2 different protocols: 3 × 3 mm and 4.5 × 4.5 mm. Quantitative assessment (foveal avascular zone diameters and area), qualitative analysis (macroscopic and microscopic levels) and Early Treatment Diabetic Retinopathy Study diabetic macular ischemia grading were performed. Artifacts were recorded. Intraclass correlation coefficients and weighted kappa values were calculated. RESULTS: Mean (SD) foveal avascular zone area was 0.695 (0.52) mm on FFA, 0.627 (0.54) mm on SS-OCTA 3 × 3 and 0.701 (0.54) mm on SS-OCTA 4.5 × 4.5 protocol. Intraclass correlation coefficients showed good agreement between FFA and SS-OCTA for both vertical diameter and foveal avascular zone area measurements. The agreement between SS-OCTA 3 × 3 and 4.5 × 4.5 was good for all quantitative measurements. Weighted kappa for diabetic macular ischemia grading showed low to fair agreement between FFA and SS-OCTA, whereas the agreement was good between two different SS-OCTA protocols. CONCLUSION: Swept-source OCTA is a reproducible technique in the assessment of macular perfusion in diabetic patients with special regards to foveal avascular zone analysis. The agreement with FFA is limited especially for diabetic macular ischemia grading. Fundus fluorescein angiography is more sensitive in identifying microaneurysms.

Effect of Mydriatic Administration on Retinal Hemodynamics in Glaucoma: An Optical Coherence Tomography Angiography Study.

PRCIS: Pupillary dilation with 0.5% tropicamide and 2.5% phenylephrine resulted in a statistically significant decrease in foveal avascular zone (FAZ) metrics in glaucoma eyes. This observation emphasizes the critical role of pupillary status in interpreting glaucomatous vascular alterations detected by optical coherence tomography angiography (OCTA). PURPOSE: The purpose of this study was to evaluate the influence of mydriatic eye drops on OCTA parameters in patients with primary open angle glaucoma (POAG). MATERIALS AND METHODS: A total of 20 POAG eyes and 20 control eyes were recruited in the study. The imaging area on the fundus was visualized by AngioPlex (Cirrus 5000 HD-OCT) using en face view of 3×3 mm and 6×6 mm preview scans. Images were generated before and after the instillation of topical 0.5% tropicamide and 2.5% phenylephrine. Optic nerve head (ONH) perfusion, ONH flux index, macular perfusion density, macular vessel density, and FAZ measurements were consecutively obtained for each session. Differences between the predilation and postdilation measurements were evaluated in POAG patients and controls. RESULTS: POAG eyes showed a statistically significant decrease in the FAZ area from a mean of 0.29-0.25 mm 2 ( P =0.037) and FAZ perimeter from a mean of 2.27-2.09 mm ( P =0.045) in the OCTA 6×6 mm scan area after tropicamide/phenylephrine instillation. Predilation and postdilation measurements of ONH perfusion and ONH flux index were significantly lower in the glaucoma group compared with controls ( P <0.05, for all). CONCLUSIONS: Topical pupillary dilation with 0.5% tropicamide and 2.5% phenylephrine results in a statistically significant reduction in the FAZ area and FAZ perimeter in POAG eyes. Further OCTA studies are needed for the diagnostic value of vascular changes due to pupil dilation in glaucoma.

Orbital schwannoma with fluid-fluid levels on MRI.

A 40-year-old man presented with a progressively growing left orbital mass producing proptosis. Orbital MRI revealed a large bilobed mass that was isointense with respect to the extraocular muscles on T1-weighted images and demonstrated heterogenous contrast enhancement. T2-weighted images revealed a markedly heterogenous internal appearance with fluid-fluid levels. The mass was completely excised in one piece. Histopathologically, the encapsulated tumor consisted mostly of spindle-shaped tumor cells with elongated nuclei forming bundles without obvious mitosis. Richly cellular areas were consistent with the Antoni A pattern, and more hypocellular edematous areas were consistent with the Antoni B pattern. Hemorrhagic and cystic areas were seen within the tumor. The tumor cells stained diffusely positive with S-100 protein. Findings were consistent with the diagnosis of orbital schwannoma. Fluid-fluid levels are usually seen in some vascular and bone tumors and soft tissue lesions. Fluid-fluid levels have previously been reported to occur in intracranial but not in orbital schwannomas. This case demonstrates that orbital schwannoma can also display fluid-fluid levels on MRI, which were thought to be due to intralesional hemorrhage in this case.