Quantitative changes in the ageing choriocapillaris as measured by swept source optical coherence tomography angiography

Abstract

AimTo analyse quantitative optical coherence tomography angiography (OCTA) parameters of choriocapillaris (CC) at the foveal, perifoveal and parafoveal regions in healthy subjects of different age.MethodsIn this observational cross-sectional study, consecutive healthy subjects underwent swept source OCTA (PLEX Elite 9000, Carl Zeiss Meditec, USA). 3×3 mm and 6×6 mm scans centred on the fovea were acquired analysed and postprocessed with thresholding and binarisation processes. The main outcome measures included CC quantitative OCTA features (perfusion density (PD), vessel length density (VLD) and vessel diameter index (VDI)) at the foveal, perifoveal and parafoveal regions, and their relationship with age.ResultsSeventy-two eyes (72 patients, mean age 47.4±19.2 years, mean axial length 24.0±0.7 mm) were included. The mean PD was statistically lower in the foveal region compared with the parafoveal region in 3×3 mm scans (p=0.009). In subjects aged 70–80, PD of the foveal region was significantly reduced compared with the perifoveal region in 6×6 mm scans (p=0.008). A strong negative correlation was found between PD and ageing in the foveal, parafoveal and perifoveal regions (p<0.001 in all analyses). Furthermore, PD in the nasal-perifoveal region was significantly lower than the temporal-perifoveal region (p=0.005). No significant correlation was found between VLD and age in all regions, whereas VDI was strictly correlated with age (p<0.001).ConclusionsWe reported in vivo a strong negative correlation between PD and ageing in the CC of healthy subjects. This reduction seems related to a reduced diameter, and not to a reduced number, of capillaries. The age-related changes were higher in the central area compared with the perifoveal area.

Morphofunctional analysis of the retina in patients with type 1 diabetes without complications after 30 years of disease

“…Perfusion density of CC was calculated through Phansalkar's thresholding (radius, 15 pixels) and binarization after removing from the analysis the CC directly beneath major superficial retinal vessels in order to eliminate potentially confounding shadow or projection artifacts (Fig. 2) 19 . CC slab was identified as a 20 μm thick starting 29 μm posterior to the RPE reference.…”

“…1). Skeletonized images were used to calculate vessel length density (VLD) as the ratio of the total skeleton area over the total scanned area 19 . Vessel tortuosity was calculated according to the method recently published by Lee Hyungwoo, et al 20 .…”

Quantitative Evaluation of Superficial Retinal Capillary Area via Optical Coherence Tomography in Healthy Individuals in Turkish Population

“…Kan damarlarını bu akım sinyalindeki hızlı değişiklikleri tanıyarak lokalize eder. Akım halindeki eritrositler tekrarlanan OKT kesitlerinde hızlı varyasyonlara yol açarlar, bu varyasyonlar intensite, faz veya hem faz hem de intensite değişiklikleri göz önüne alarak ölçülür ve OKTA akım görüntüleri oluşturulur (5)(6)(7)(8)(9) . Yine OKTA görüntülemede sinyal derinliği ve segmentasyon çok önem göstermektedir.…”

Pearls and Pitfalls of Optical Coherence Tomography Angiography Imaging: A Review

“…• The fractal dimension, which is a mathematical parameter that describes the complexity of a biological structure [24]. Previous studies on the CC have investigated the distribution, size, and percentage of flow voids (also called signal voids), which are small dark regions that alternate with granular bright areas, the latter thought to represent CC flow, and the former more likely to be secondary to CC vascular dropout or flow reduction [2,25,26].…”

“…Given that previous imaging techniques have significant limitations for the evaluation of the CC, OCTA has evolved into a key technology for investigation of the CC [2,25,26].…”