Macular perfusion parameters in different angiocube sizes: does the size matter in quantitative optical coherence tomography angiography?

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Re: Dolz-Marco et\ua0al.: Choroidal and sub-retinal pigment epithelium caverns: multimodal imaging and correspondence with Friedman lipid globules (Ophthalmology. 2018;125:1287-1301)

Refers to: Rosa Dolz-Marco, Jay P. Glover, Orly Gal-Or, Katie M. Litts, Jeffrey D. Messinger, Yuhua Zhang, Mariano Cozzi, Marco Pellegrini, K. Bailey Freund, Giovanni Staurenghi, Christine A. Curcio Choroidal and Sub-Retinal Pigment Epithelium Caverns Ophthalmology, Volume 125, Issue 8, August 2018, Pages 1287-130

Comparison of methods to quantify macular and peripapillary vessel density in optical coherence tomography angiography.

PURPOSE:To compare macular and peripapillary vessel density values calculated on optical coherence tomography angiography (OCT-A) images with different algorithms, elaborate conversion formula, and compare the ability to discriminate healthy from affected eyes. METHODS:Cross-sectional study of healthy subjects, patients with diabetic retinopathy, and glaucoma patients (44 eyes in each group). Vessel density in the macular superficial capillary plexus (SCP), deep capillary plexus (DCP), and the peripapillary radial capillary plexus (RCP) were calculated with seven previously published algorithms. Systemic differences, diagnostic properties, reliability, and agreement of the methods were investigated. RESULTS:Healthy eyes exhibited higher vessel density values in all plexuses compared to diseased eyes regardless of the algorithm used (p<0.01). The estimated vessel densities were significantly different at all the plexuses (p<0.0001) as a function of method used. Inter-method reliability and agreement was mostly poor to moderate. A conversion formula was available for every method, except for the conversion between multilevel and fixed at the DCP. Substantial systemic, non-constant biases were evident between many algorithms. No algorithm outperformed the others for discrimination of patients from healthy subjects in all the retinal plexuses, but the best performing algorithm varied with the selected plexus. CONCLUSIONS:Absolute vessel density values calculated with different algorithms are not directly interchangeable. Differences between healthy and affected eyes could be appreciated with all methods with different discriminatory abilities as a function of the plexus analyzed. Longitudinal monitoring of vessel density should be performed with the same algorithm. Studies adopting vessel density as an outcome measure should not rely on external normative databases

Choroidal Rift: A New OCT Finding in Eyes with Central Serous Chorioretinopathy

Central serous chorioretinopathy (CSC) is a complex and not entirely understood retinal disease. The aim of our research was to describe a novel optical coherence tomography (OCT) finding named &ldquo;choroidal rift&rdquo;, which may be identified in the choroid of eyes with CSC. We collected data from 357 patients (488 eyes) with CSC who had structural OCT and OCT angiography (OCTA) scans obtained. Choroidal rifts were identified as polygonal (and not round-shaped) hyporeflective lesions without hyperreflective margins. Choroidal rifts had to be characterized by a size superior to that of the largest choroidal vessel. Finally, hyporeflective lesions were graded as choroidal rifts only if these lesions had a main development perpendicular to the retinal pigment epithelium. OCT analysis allowed the identification of choroidal rifts in ten eyes from nine patients, all with chronic CSC, with an estimated prevalence rate of 2.1%. In three out of ten cases with choroidal rifts, these lesions spanned all the choroidal layers. In the remaining cases, choroidal rifts only partially spanned the choroidal thickness. In OCTA, choroidal rifts were characterized by the absence of flow. Combining structural OCT and OCTA information, we hypothesized that choroidal rifts may represent interruptions of the choroidal stroma in correspondence of fragile regions (in between expanded larger-sized choroidal vessels). Choroidal rift represents a novel OCT feature, which may characterize eyes with chronic CSC and may have a role in the development of irreversible chorio-retinal changes