ABSTRACT
AIM: To evaluate the characteristics of choriocapillary blood flow in different patients with diabetic retinopathy(DR)based on the measurement of choriocapillaris(CC)perfusion density(PFD)using ultra-high-speed swept-source optical coherence tomography angiography(SS-OCTA)METHODS: The cross-sectional observational study was conducted on 139 cases(139 eyes)who admitted to the Second People's Hospital of Hefei, including 115 DR cases(115 eyes)and 24 control cases(24 eyes). The color retinal images were graded according to the Early Treatment Diabetic Retinopathy Study(ETDRS)scale, and the DR eyes were classified into non-DR group, nonproliferative diabetic retinopathy(NPDR)group, NPDR combined with diabetic macular edema(DME)group and proliferative diabetic retinopathy(PDR)group. The ultra-high-speed SS-OCTA was used to scan a 3mm×3mm region centered on the macular central fovea, the CC perfusion area was measured by the built-in software, and PFD was calculated. Multivariable linear regressions were used to evaluate the correlation between PFD of CC and DR degree.RESULTS: The degree of DR had a correlation with blood perfusion of CC after adjusting for various confounding factors. When compared to the control group, the PFD of CC in the central fovea of the NPDR group decreased by 9.358 units(95%CI -18.484～-0.232, P=0.045)and 9.284 units in the paracentral fovea(95%CI -18.487～-0.090, P=0.048); In the NPDR combined with DME group, the central fovea CC PFD decreased by 18.173 units(95%CI -28.583～-7.762, P=0.001), while the paracentral fovea decreased by 17.032 units(95%CI -27.521～-6.544, P=0.002); In the PDR group, the central fovea CC PFD decreased by 28.309 units(95%CI -39.978～-16.640, P<0.001), while the paracentral fovea decreased by 25.841 units(95%CI -37.597～-14.085, P<0.001).CONCLUSION: The macular perfusion can be objectively quantified by the measurement of CC PFD with ultra-high-speed SS-OCTA. The CC PFD in the macular region was significantly reduced in more advanced stages of DR. Furthermore, future research should focus on longitudinal studies in the causal relationship between CC perfusion and DR progression.
ABSTRACT
Purpose: To evaluate the choriocapillaris flow deficits (CCFD) on swept-source optical coherence tomography angiography (SS-OCTA) in eyes with unilateral polypoidal choroidal vasculopathy (PCV), fellow unaffected eyes, and to compare them with age-matched healthy controls. Methods: This study was a cross-sectional study which included treatment-naïve eyes with unilateral PCV (group 1), fellow unaffected eyes of patients with PCV (group 2), and normal eyes (group 3). Using the SS-OCTA, the Choriocapillaris (CC) slab was segmented from the structural optical coherence tomography (OCT) and the corresponding flow map was multiplied after signal compensation. The resultant image was evaluated for CCFD in equidistant squares measuring 1 × 1 mm, 1.5 × 1.5 mm, 2 × 2 mm, 2.5 × 2.5 mm, 3 × 3 mm, and 6 × 6 mm centered on the fovea. Results: The percentage of flow deficits were significantly increased (one-way ANOVA, P = 0.003 and P = 0.049) in the eyes with PCV as compared to the fellow eyes, and age-matched healthy controls. In the multiple pairwise comparison using post hoc Bonferroni, CCFD of 1 mm in group 1 and 2 (P = 0.019), group 1 and 3 (P = 0.003), and CCFD of 1.5 mm in group 1 and 3 (P = 0.044) were statistically significant. Correlation analysis showed no significant correlation between CCFD, age, Best corrected visual acuity (BCVA), foveal thickness (FT), and subfoveal choroidal thickness (SFCT) in our study. Linear regression analysis showed that the CCFD was negatively correlated with the distance from the foveal center in group 1 (? = ?0.613, P = 0.046). Conclusion: Eyes with PCV demonstrated a significant flow impairment in the choriocapillaris layer as compared to the fellow unaffected eyes and age-matched healthy eyes.
ABSTRACT
A structurally and functionally intact choroid tissue is vitally important for the retina function. Although central retinal artery is responsible to supply the inner retina, choroidal vein network is responsible for the remaining one-third of the external part. Abnormal choroidal blood flow leads to photoreceptor dysfunction and photoreceptor death in the retina, and the choroid has vital roles in the pathophysiology of many diseases such as central serous chorioretinopathy, age-related macular degeneration, pathologic myopia, Vogt–Koyanagi–Harada disease. Biomarkers of choroidal diseases can be identified in various imaging modalities that visualize the choroid. Indocyanine green angiography enables the visualization of choroid veins under the retinal pigment epithelium and choroidal blood flow. New insights into a precise structural and functional analysis of the choroid have been possible, thanks to recent progress in retinal imaging based on enhanced depth imaging (EDI) and swept-source optical coherence tomography (SS-OCT) technologies. Long-wavelength SS-OCT enables the choroid and the choroid–sclera interface to be imaged at greater depth and to quantify choroidal thickness profiles throughout a volume scan, thus exposing the morphology of intermediate and large choroidal vessels. Finally, OCT angiography allows a dye-free evaluation of the blood flow in the choriocapillaris and in the choroid. We hereby review different imaging findings of choroidal diseases that can be used as biomarkers of activity and response to the treatment.
ABSTRACT
A 26-year-old healthy male patient's fundus revealed findings consistent with torpedo maculopathy. Swept-source optical coherence tomography (OCT) showed a dome-shaped elevation of the retina at the level of ellipsoid zone. On OCT angiography segmented at the level of the choriocapillaris, a cluster of convoluted fine vessels was seen, and further, deeper scans of the larger choroidal vessels showed a slower flow. From these observations along with the embryological correlation of choriocapillaris development, a possibility of an abnormality preventing proper fenestration of the choriocapillaris along the horizontal raphe being responsible for this anomaly is suggested.