Inter-Individual Topographic Variation of Choroidal Thickness in Healthy Eyes on Swept-Source Optical Coherence Tomography.

Purpose: To investigate the topographic characters of inter-individual variations of the macular choroidal thickness (CT). Methods: This was a retrospective study. Macular CT data for 900 0.2 × 0.2-mm grids from 410 healthy eyes were collected from swept-source optical coherence tomography. Following the analysis of factors associated with mean CT, the ß-coefficients of the included associated factors in each grid were summarized for choroidal thickness changes analysis. Additionally, the coefficient of variance (CoV), coefficient of determination (CoD), and coefficient of variance unexplained (CoVU) for CT were calculated in each individual grid to investigate the inter-individual choroidal variations pattern. Results: Sex (ß = -17.26, female vs. male), age (ß = -1.61, per 1 year), and axial length (ß = -18.62, per 1 mm) were associated with mean macular CT. Females had a thinner choroid in all 900 grids (0.5-26.9 µm). As age increased, the CT noticeably decreased (8.74-19.87 µm per 10 years) in the temporal regions. With axial length elongation, the thinning (7.94-24.91 µm per 1 mm) was more evident in subfoveal and nasal regions. Both the CoV (34.69%-58.00%) and CoVU (23.05%-40.78%) were lower in the temporal regions, whereas the CoD (18.41%-39.66%) was higher in the temporal regions. Conclusions: Choroidal thinning is more predominant in the subfoveal and nasal regions with axial length elongation, but in the temporal region with aging. The inter-individual variation of CT is higher and less determined by sex, age, or axial length in the nasal regions. Translational Relevance: Topographic variation should be considered when interpreting choroidal thickness.

Histologic correlates of "Choroidal abnormalities" in Neurofibromatosis type 1 (NF1).

Neurofibromatosis type 1 (NF1) is a rare autosomal dominant disorder characterized by proliferation of cells from neural crest origin. The most common manifestations are cutaneous, neurologic, skeletal and ocular. The distinction of NF1 from other syndromes with multiple café-au-lait macules may be difficult in the pediatric age group, and ocular findings, especially Lisch nodules (i.e., melanocytic hamartomas on the irides), are a useful, early diagnostic tool. In recent years, novel ocular manifestations descriptively referred to as "choroidal abnormalities", choroidal "hyperpigmented spots" and "retinal vascular abnormalities" have been recognized in NF1. Choroidal abnormalities (CA) appear as bright patchy nodules that can be best detected with near-infrared ocular coherence tomography imaging (NIR-OCT). Because of their high specificity and sensitivity for NF1, CA have been added as an ocular diagnostic criterion of NF1 as an alternative to Lisch nodules. Although CA are important ocular diagnostic criteria for NF1, the histologic correlates are controversial. We present the postmortem ocular pathology findings of an NF1 patient for whom clinical notes and ocular imaging were available. Findings in this patient included choroidal hyperpigmented spots on funduscopy and retinal vascular abnormalities, both of which have been reported to be closely associated with CA. Histologic examination of the eyes showed multiple clusters of melanocytes of varying sizes in the choroid. Pathologic review of 12 additional postmortem eyes from 6 NF1 patients showed multiple, bilateral choroidal melanocytic aggregates in all eyes. These findings suggest that the CA seen on NIR-OCT and the hyperpigmented spots seen clinically in NF1 patients are manifestations of multifocal choroidal melanocytic clusters, consistent with choroidal melanocytic hamartomas. Lisch nodules, often multiple, were present in all eyes with morphology that differed from the choroidal hamartomas. As such, although CA and Lisch nodules are melanocytic hamartomas, there are clear phenotypical differences in their morphologies.

Peripapillary atrophy area predicts the decrease of macular choroidal thickness in young adults during myopia progression.

OBJECTIVE: This study aimed to investigate the influence of peripapillary atrophy (PPA) area and axial elongation on the longitudinal changes in macular choroidal thickness (ChT) in young individuals with myopia. METHODS AND ANALYSIS: In this longitudinal investigation, 431 eyes-342 categorised as non-high myopia (non-HM) and 89 as HM-were examined for 2 years. Participants were examined with swept-source optical coherence tomography. The macular ChT, PPA area and axial length (AL) were measured at baseline and follow-up visits. Multiple regression analysis was performed to identify factors associated with ChT changes. The areas under the receiver operating characteristic curves were analysed to ascertain the predictive capacity of the PPA area and axial elongation for the reduction in macular ChT. RESULTS: Initial measurements revealed that the average macular ChT was 240.35±56.15 µm in the non-HM group and 198.43±50.27 µm in the HM group (p<0.001). It was observed that the HM group experienced a significantly greater reduction in average macular ChT (-7.35±11.70 µm) than the non-HM group (-1.85±16.95 µm, p=0.004). Multivariate regression analysis showed that a greater reduction of ChT was associated with baseline PPA area (ß=-26.646, p<0.001) and the change in AL (ß=-35.230, p<0.001). The combination of the baseline PPA area with the change in AL was found to be effective in predicting the decrease in macular ChT, with an area under the curve of 0.741 (95% CI 0.694 to 0.787). CONCLUSION: Over 2 years, eyes with HM exhibit a more significant decrease in ChT than those without HM. Combining the baseline PPA area with the change in AL could be used to predict the decrease of macular ChT.

PGKD-Net: Prior-guided and Knowledge Diffusive Network for Choroid Segmentation.

The thickness of the choroid is considered to be an important indicator of clinical diagnosis. Therefore, accurate choroid segmentation in retinal OCT images is crucial for monitoring various ophthalmic diseases. However, this is still challenging due to the blurry boundaries and interference from other lesions. To address these issues, we propose a novel prior-guided and knowledge diffusive network (PGKD-Net) to fully utilize retinal structural information to highlight choroidal region features and boost segmentation performance. Specifically, it is composed of two parts: a Prior-mask Guided Network (PG-Net) for coarse segmentation and a Knowledge Diffusive Network (KD-Net) for fine segmentation. In addition, we design two novel feature enhancement modules, Multi-Scale Context Aggregation (MSCA) and Multi-Level Feature Fusion (MLFF). The MSCA module captures the long-distance dependencies between features from different receptive fields and improves the model's ability to learn global context. The MLFF module integrates the cascaded context knowledge learned from PG-Net to benefit fine-level segmentation. Comprehensive experiments are conducted to evaluate the performance of the proposed PGKD-Net. Experimental results show that our proposed method achieves superior segmentation accuracy over other state-of-the-art methods. Our code is made up publicly available at: https://github.com/yzh-hdu/choroid-segmentation.

Vascular changes of the choroid and their correlations with visual acuity in diabetic retinopathy.

Objective: To investigate changes in the choroidal vasculature and their correlations with visual acuity in diabetic retinopathy (DR). Methods: The cohort was composed of 225 eyes from 225 subjects, including 60 eyes from 60 subjects with healthy control, 55 eyes from 55 subjects without DR, 46 eyes from 46 subjects with nonproliferative diabetic retinopathy (NPDR), 21 eyes from 21 subjects with proliferative diabetic retinopathy (PDR), and 43 eyes from 43 subjects with clinically significant macular edema (CSME). Swept-source optical coherence tomography (SS-OCT) was used to image the eyes with a 12-mm radial line scan protocol. The parameters for 6-mm diameters of region centered on the macular fovea were analyzed. Initially, a custom deep learning algorithm based on a modified residual U-Net architecture was utilized for choroidal boundary segmentation. Subsequently, the SS-OCT image was binarized and the Niblack-based automatic local threshold algorithm was employed to calibrate subfoveal choroidal thickness (SFCT), luminal area (LA), and stromal area (SA) by determining the distance between the two boundaries. Finally, the ratio of LA and total choroidal area (SA + LA) was defined as the choroidal vascularity index (CVI). The choroidal parameters in five groups were compared, and correlations of the choroidal parameters with age, gender, duration of diabetes mellitus (DM), glycated hemoglobin (HbA1c), fasting blood sugar, SFCT and best-corrected visual acuity (BCVA) were analyzed. Results: The CVI, SFCT, LA, and SA values of patients with DR were found to be significantly lower compared to both healthy patients and patients without DR (P < 0.05). The SFCT was significantly higher in NPDR group compared to the No DR group (P < 0.001). Additionally, the SFCT was lower in the PDR group compared to the NPDR group (P = 0.014). Furthermore, there was a gradual decrease in CVI with progression of diabetic retinopathy, reaching its lowest value in the PDR group. However, the CVI of the CSME group exhibited a marginally closer proximity to that of the NPDR group. The multivariate regression analysis revealed a positive correlation between CVI and the duration of DM as well as LA (P < 0.05). The results of both univariate and multivariate regression analyses demonstrated a significant positive correlation between CVI and BCVA (P = 0.003). Conclusion: Choroidal vascular alterations, especially decreased CVI, occurred in patients with DR. The CVI decreased with duration of DM and was correlated with visual impairment, indicating that the CVI might be a reliable imaging biomarker to monitor the progression of DR.

Choroidal Vascularity Index and Choroidal Structural Changes in Children With Nephrotic Syndrome.

Purpose: To investigate the choroidal vascularity index (CVI) and choroidal structural changes in children with nephrotic syndrome. Methods: This was a cross-sectional study involving 45 children with primary nephrotic syndrome and 40 normal controls. All participants underwent enhanced depth imaging-optical coherence tomography examinations. An automatic segmentation method based on deep learning was used to segment the choroidal vessels and stroma, and the choroidal volume (CV), vascular volume (VV), and CVI within a 4.5 mm diameter circular area centered around the macular fovea were obtained. Clinical data, including blood lipids, serum proteins, renal function, and renal injury indicators, were collected from the patients. Results: Compared with normal controls, children with nephrotic syndrome had a significant increase in CV (nephrotic syndrome: 4.132 ± 0.464 vs. normal controls: 3.873 ± 0.574; P = 0.024); no significant change in VV (nephrotic syndrome: 1.276 ± 0.173 vs. normal controls: 1.277 ± 0.165; P = 0.971); and a significant decrease in the CVI (nephrotic syndrome: 0.308 [range, 0.270-0.386] vs. normal controls: 0.330 [range, 0.288-0.387]; P < 0.001). In the correlation analysis, the CVI was positively correlated with serum total protein, serum albumin, serum prealbumin, ratio of serum albumin to globulin, and 24-hour urine volume and was negatively correlated with total cholesterol, low-density lipoprotein cholesterol, urinary protein concentration, and ratio of urinary transferrin to creatinine (all P < 0.05). Conclusions: The CVI is significantly reduced in children with nephrotic syndrome, and the decrease in the CVI parallels the severity of kidney disease, indicating choroidal involvement in the process of nephrotic syndrome. Translational Relevance: Our findings contribute to a deeper understanding of how nephrotic syndrome affects the choroid.

Three-dimensional choroidal contour mapping in healthy population.

Purpose was to study 3-dimensional choroidal contour at choroidal inner boundary (CIB) and choroidal outer boundary (COB) in healthy eyes. Healthy eyes imaged on wide field swept-source optical coherence tomography were included. Delineation of CIB and COB was done based on our previously reported methods. Quantitative analysis of the surfaces of CIB and COB was based on analyzing best fit spherical radius (R) (overall and sectoral). One hundred and seven eyes of 74 subjects with a mean age of 46.4 ± 19.3 years were evaluated. Overall, R COB (mean ± SD: 22.5 ± 4.8 mm) < R CIB (32.4 ± 9.4 mm). Central sector had the least R at COB (7.2 ± 5.9 mm) as well as CIB (25.1 ± 14.3 mm) across all age groups. Regression analysis between R (CIB) and age (r = -0.31, r2 = 0.09) showed negative correlation (P < 0.001) and that between R (COB) and age was positive (r = 0.26, r2 = 0.07) (P = 0.01). To conclude, central sector is the steepest sector in comparison to all the other sectors. This is indicative of a prolate shape of choroidal contour at CIB and COB. Outer boundary of choroid is steeper than inner boundary across all age groups. However, with ageing, outer boundary becomes flatter and inner boundary becomes steeper.

Choroidal macrovascular and capillary alterations in eyes with idiopathic epiretinal membranes.

PURPOSE: To evaluate the choroidal vascular alterations and effect of surgical treatment in the setting of idiopathic epiretinal membranes. METHODS: The structure of the choroid was studied in 33 patients with unilateral idiopathic epiretinal membrane using optical coherence tomography with enhanced depth imaging and optical coherence tomography angiography. Eyes with epiretinal membrane underwent 25-gauge vitrectomy with epiretinal membrane and internal limiting membrane peeling. The choroidal vascularity index, Haller layer/choroidal thickness ratio, and choriocapillaris flow density were used to evaluate changes in choroidal structure after surgery and compare with the healthy fellow eyes. RESULTS: The choroidal vascularity index and Haller layer/choroidal thickness ratio of the eyes with epiretinal membrane were higher than those of the fellow eyes at baseline (p=0.009 and p=0.04, respectively) and decreased postoperatively compared with preoperative values (p=0.009 and p=0.001, respectively). The choriocapillaris flow of eyes with epiretinal membrane was lower than that of the fellow eyes at baseline (p=0.001) and increased after surgery compared with the preoperative value (p=0.04). The choroidal vascularity index, Haller layer/choroidal thickness ratio, and choriocapillaris flow values of the healthy fellow eyes were comparable at baseline and final visit. In eyes with epiretinal membrane, the final choroidal vascularity index correlated with the final choriocapillaris flow (r=-0.749, p=0.008) in the multivariate analysis. CONCLUSION: Idiopathic epiretinal membrane appears to affect the choroidal structure with increased choroidal vascularity index and Haller layer/ choroidal thickness ratio and decreased choriocapillaris flow. These macrovascular (choroidal vascularity index and Haller layer/choroidal thickness) and microvascular (choriocapillaris flow) alterations appear to be relieved by surgical treatment of the epiretinal membranes.

Predicting central choroidal thickness from colour fundus photographs using deep learning.

The estimation of central choroidal thickness from colour fundus images can improve disease detection. We developed a deep learning method to estimate central choroidal thickness from colour fundus images at a single institution, using independent datasets from other institutions for validation. A total of 2,548 images from patients who underwent same-day optical coherence tomography examination and colour fundus imaging at the outpatient clinic of Jichi Medical University Hospital were retrospectively analysed. For validation, 393 images from three institutions were used. Patients with signs of subretinal haemorrhage, central serous detachment, retinal pigment epithelial detachment, and/or macular oedema were excluded. All other fundus photographs with a visible pigment epithelium were included. The main outcome measure was the standard deviation of 10-fold cross-validation. Validation was performed using the original algorithm and the algorithm after learning based on images from all institutions. The standard deviation of 10-fold cross-validation was 73 µm. The standard deviation for other institutions was reduced by re-learning. We describe the first application and validation of a deep learning approach for the estimation of central choroidal thickness from fundus images. This algorithm is expected to help graders judge choroidal thickening and thinning.

Mean Amplitude of Diurnal Variation of Sub-Foveal Choroidal Thickness among Adults with Healthy Eyes Visiting Outpatient Department of a Tertiary Eye Care Centre.

Introduction: The choroid, particularly the choroidal vasculature, plays an important role in the pathophysiology of various ocular diseases. Diurnal variation in the thickness of the choroid has been reported in previous studies. This study aimed to find the mean amplitude of diurnal variation of sub-foveal choroidal thickness among adults with healthy eyes visiting the outpatient Department of a tertiary eye care centre. Methods: A descriptive cross-sectional study was conducted among adults with healthy eyes presenting to the outpatient Department of a tertiary eye care centre from 1 February 2023 to 3 June 2023 after obtaining ethical approval from the Institutional Review Committee. After a comprehensive medical eye examination, sub-foveal choroidal thickness measurement was performed using enhanced depth imaging optical coherence tomography at the baseline and subsequent interval afterwards. A convenience sampling method was used. The point estimate was calculated at a 95% Confidence Interval. Results: Among 60 eyes, the mean amplitude of the diurnal variation of subfoveal choroidal thickness was 35.16±14.08 microns (31.59-38.72, 95% Confidence Interval). The mean amplitude for the right eye was 36.30±14.08 microns, and for the left eye, it was 34.23±14.08 microns. Conclusions: The amplitude of diurnal variation of subfoveal choroidal thickness from this study was found to be similar to other studies done in international settings. Keywords: choroid; circadian rhythm; cross-sectional study; Ophthalmology.

Retinal and Choroidal Vascularity Evaluation in Pediatric Radiologically Isolated Syndrome and Multiple Sclerosis.

BACKGROUND: To assess vessel density (VD) and flow of retinal plexuses and peripapillary region related with the pediatric radiologically isolated syndrome (RIS) and multiple sclerosis (MS). METHODS: We analyzed 24 eyes of 12 participants with the diagnosis of RIS, 24 eyes of 12 participants with the diagnosis of MS, and 26 eyes of 13 age- and sex-matched healthy controls in this prospective, cross-sectional study. The superficial capillary plexus (SCP) and deep capillary plexus, foveal avascular zone, and the flow of choriocapillaris were investigated using optical coherence tomography angiography. RESULTS: Parafoveal VD and all subregion parameters in SCP were significantly decreased in the MS group compared with the controls, whereas only nasal and inferior VD were significantly decreased in the pediatric RIS group compared with the controls. Ganglion cell layer (GCL) thickness of all subregions of the inner ring was significantly decreased in the pediatric MS group compared with the control group. No significant difference was observed between the pediatric RIS group and the control group regarding thickness. CONCLUSIONS: We showed lower parafoveal VD in all subregions of SCP in pediatric MS, whereas only parafoveal nasal and inferior VD were decreased in pediatric RIS. GCL thickness of inner ring was significantly decreased in the pediatric MS, whereas GCL thickness did not change in pediatric RIS. Therefore, a decrease of parafoveal nasal and inferior VD without a decrease in thickness implies an early impairment of microvasculature in the RIS before impairment of thickness and that microvascular alterations begin from highly vascular superficial parafovea.

Choroid cavitation associated with macular coloboma. Multimodal study. Image en face.

Intrachoroidal cavitation is a finding identified with OCT initially described in myopic patients, it also appears in non-myopic patients. It can occur in both the peripapillary area and the posterior pole. Macular coloboma is a defect of embryonic development of the posterior pole, in structural OCT the absence of the retinal pigment epithelium and choroidal vessels is essential. In this case, intrachoroidal cavitation circumscribes the macular coloboma, in the absence of an intercalary membrane. The en face image allows us to assess the relationship between the two structures as well as their magnitude.

Automatic segmentation of layers in chorio-retinal complex using Graph-based method for ultra-speed 1.7 MHz wide field swept source FDML optical coherence tomography.

The posterior segment of the human eye complex contains two discrete microstructure and vasculature network systems, namely, the retina and choroid. We present a single segmentation framework technique for segmenting the entire layers present in the chorio-retinal complex of the human eye using optical coherence tomography (OCT) images. This automatic program is based on the graph theory method. This single program is capable of segmenting seven layers of the retina and choroid scleral interface. The graph theory was utilized to find the probability matrix and subsequent boundaries of different layers. The program was also implemented to segment angiographic maps of different chorio-retinal layers using "segmentation matrices." The method was tested and successfully validated on OCT images from six normal human eyes as well as eyes with non-exudative age-related macular degeneration (AMD). The thickness of microstructure and microvasculature for different layers located in the chorio-retinal segment of the eye was also generated and compared. A decent efficiency in terms of processing time, sensitivity, and accuracy was observed compared to the manual segmentation and other existing methods. The proposed method automatically segments whole OCT images of chorio-retinal complex with augmented probability maps generation in OCT volume dataset. We have also evaluated the segmentation results using quantitative metrics such as Dice coefficient and Hausdorff distance This method realizes a mean descent Dice similarity coefficient (DSC) value of 0.82 (range, 0.816-0.864) for RPE and CSI layer.

El espacio supracoroideo en pacientes afectados por retinosis pigmentaria / The suprachoroidal space in patients affected by retinitis pigmentosa

Antecedentes y objetivo: El espacio supracoroideo (SCS) es una estructura teórica que se sitúa entre el borde interno de la esclera y el límite externo del coroides. El SCS está siendo estudiado por sus posibles usos como vía para la administración de medicamentos y por técnicas quirúrgicas innovadoras para el tratamiento de muchas enfermedades retinianas. La retinitis pigmentosa (RP) es un grupo de trastornos hereditarios y progresivos caracterizados por el detrimento gradual de fotorreceptores que conduce a una discapacidad visual que se manifiesta típicamente como hemeralopía y pérdida progresiva del campo visual. El objetivo del estudio fue definir la morfología de los márgenes coroideos externos mediante el uso de tomografía de coherencia óptica de barrido (SS-OCT) en la RP.Materiales y métodosEstudio observacional retrospectivo diseñado para evaluar la presencia del ESC en la RP. Realizamos SS-OCT en un grupo de 55 pacientes afectados por RP (26 hombres y 29 mujeres, 110 ojos) con una edad media de 51,8±13,7 años. En el grupo de control incluimos a 28 sujetos sanos (6 hombres y 22 mujeres, 56 ojos) con una edad media de 48,8±16,6 años.ResultadosLas imágenes OCT permitieron delinear de manera precisa el margen coroideo externo y el margen escleral interno en los 110 ojos. En el grupo RP se detectó el ESC en 47 de los 110 ojos (42,7%), en el grupo de control se detectó el ESC en 11 ojos (19,6%).Los sujetos del grupo RP con SCS visibles presentaron un menor grosor retiniano (168,4 micrones) en comparación con aquellos con SCS visibles (211,2 micrones, p=0,007). (AU)

Background and objective: The suprachoroidal space (SCS) is a theoretical structure which can be demonstrated between the inner border of the sclera and the outer boundary of the choroid. SCS is being studied for its potential uses as a route for drug delivery and innovative surgical techniques for the treatment of many retinal diseases. Retinitis pigmentosa (RP) is a group of inherited eye disorders characterized by a gradual loss of photoreceptors, resulting in vision impairment, which typically presents as night blindness and progressive visual field loss. The purpose of the study is to define the morphology of outer choroidal margins by means of SS-OCT in RP.Material and methodThis is a retrospective observational study designed to evaluate the presence of SCS in RP. We performed swept source optical coherence tomography (SS-OCT) in a group of 55 patients affected by RP (26 males and 29 females, 110 eyes) with a mean age of 51.8±13.7 years. In the control group, we included 28 healthy subjects (6 males and 22 females, 56 eyes) with a mean age of 48.8±16.6 years.ResultsOCT scans allowed the outer choroidal margin and inner scleral margin to be delineated with certainty in all 110 eyes. In the RP group SCS was detected in 47 of 110 eyes (42.7%), in the control group SCS was detected in 11 eyes (19.6%).Subjects with SCS visible (RP group) had reduced retinal thickness (168.4μm) compared to those with not visible SCS (211.2μm, p=0.007). (AU)

Assessment of macular choroidal and retinal thickness: a cohort study in Tibetan healthy children.

This research investigates the distribution, progressive changes, and contributing factors of macular choroidal and retinal thickness in Tibetan children utilizing swept-source optical coherence tomography (SS-OCT). The Lhasa childhood study recruited 1632 students from seven primary schools in Lhasa. These participants underwent OCT and ophthalmological evaluations, encompassing retinal and choroidal thickness measurements, refractive error, axial length (AL), and systemic examinations. The median age of the scholars was 8.57 ± 0.50 years with a median spherical equivalent (SE) of 0.19 ± 1.28D. Multivariate regression analysis revealed that thinner macular choroid thickness was correlated with lower value of SE, worse best-corrected visual acuity, higher mean arterial blood pressure (MABP) and boys, while retinal thickness was associated with better image quality and lower value of SE. The choroid and retina were significantly thinner in myopic children. SE was positively related to the thickness of all choroidal and full retinal subregions. In comparison to baseline data from 20 months prior, most regions of the full retina had significantly thinned. Choroidal thickness of Tibetan children is thinner than that of same-age children from other regions. Thinning of retina, the outer-sector GCC and GCIPL may be specified as a follow-up and prognostic indicator for myopia.

The effect of polycythemia vera on choroidal thickness and retrobulbar blood flow.

BACKGROUND: To evaluate the choroidal thickness and retrobulbar hemodynamic parameters in polycythemia vera (PV) patients in comparison with healthy individuals, and to investigate the relationship of these values with blood hematocrit levels. METHODS: This prospective study included the 35 eyes of 35 PV patients and the 30 eyes of 30 healthy individuals. Choroidal thickness was measured at the subfoveal area and at 500 µm intervals nasal and temporal to the fovea up to a distance of 1500 µm. Color Doppler ultrasonography (CDU) was used to evaluate the retrobulbar vessels. Complete blood count values were recorded. RESULTS: Choroidal thickness was found to be significantly lower in the PV group than in the control group at the subfoveal, nasal 500, and temporal 500 and 1000 µm measurement points (p = 0.01, p = 0.011, p = 0.04, p = 0.045, respectively). The central retinal artery (CRA) peak systolic velocity (PSV) and end diastolic velocity (EDV) values and the ophthalmic artery (OA) PSV value were significantly lower in the PV group than in the control group (p < 0.001, p < 0.001, p = 0.019, respectively). No significant difference was present between the groups in terms of CRA and OA resistive index (RI) and pulsatile index (PI) values (p = 0.388, p = 0.564, p = 0.897, p = 0.693, respectively). A negative correlation was found between the blood hematocrit levels and the subfoveal, nasal 500 µm, and temporal 500 µm choroidal thickness measurements and the CRA PSV and EDV and the OA PSV values. CONCLUSIONS: PV may cause microvascular changes and lead to ocular vascular complications by affecting the choroidal and retrobulbar blood flow.

Choroidal remodeling following different anti-VEGF therapies in neovascular AMD.

The purpose of this study was to investigate choroidal morphology remodeling in AMD-associated type 1 macular neovascularization using two different anti-VEGF drugs. We registered 73 treatment-naïve eyes with a diagnosis of exudative AMD and type 1 MNV. Patients received 3 monthly intravitreal aflibercept (n = 36, aflibercept group [AG]) or brolucizumab (n = 37, brolucizumab group [BG]). Baseline best-corrected visual acuity (BCVA) and anatomical (structural optical coherence tomography) parameters were collected at "T1 control", before the loading phase (LP) of intravitreal injection, and at "T2 control", 1 month after the last injection. The main outcomes measured were choroidal vascularity index (CVI), sub-foveal choroidal thickness (SFCT), and central macular thickness (CMT). Our results displayed significant SFCT reduction in both groups between T1 and T2 (p < 0.05), We did not find choroidal vascularity modifications (p > 0.05) after the loading aflibercept injections. Moreover, only the BG displayed a significant choroidal remodeling (stromal choroidal area [SCA], total choroidal area [TCA] and CVI) at T2 (p < 0.05). In particular, a relevant stromal and total choroidal volume reduction was noted, accompanied by an increase in CVI. To conclude, the latter modifications of the choroidal morphology were found significant between two groups (p < 0.05). Our analysis showed a significant impact of brolucizumab on choroidal morphology in eyes affected by type 1 nAMD. This effect was found relevant when compared with aflibercept.

Effects of age and axial length on choroidal stratified structure in normal eyes.

To quantify the choroidal structures of normal eyes by optical coherence tomography (OCT)-based binarization and evaluate the relationships among age, refractive power, and ocular axial length. This was a retrospective observational study. One hundred and eighty nine eyes of 189 subjects without ocular diseases were examined by enhanced depth imaging (EDI)-OCT. A choroidal OCT horizontal image with a width of 1500 µm centered on the fovea was binarized. The lumen, stroma, and total choroidal area in the choriocapillaris (CC), Sattler's layer (SL), and Haller's layer (HL) were measured, and the ratio of the luminal area to total choroidal area (L/C ratio) was calculated. Multiple regression analysis was performed for choroidal parameters in each choroidal layer and for age, refractive power, and ocular axial length. Multiple regression analysis showed that an older age was significantly correlated with a lower choroidal area and the L/C ratio in all choroidal layers (each P < 0.05). A Long axial length was significantly associated with lower SL and HL (P < 0.05), but not with refractive power. In the choroid of normal eyes, age-related decreases in the choroidal area and L/C ratio were associated with all choroidal layers, and elongation of the axial length was associated with thinning of SL and HL.

Insights into the pattern of choroidal vascularity index changes in idiopathic macular hole.

This retrospective study aimed to investigate the changes in choroidal vascularity index (CVI) before and after surgery for idiopathic macular hole (MH). Enhanced depth imaging optical coherence tomography (EDI-OCT) images were analyzed at baseline and at 1-week, 1-month, and 3-month postoperative visits. A total of 97 patients (97 eyes) were included in the study. At baseline, overall CVI and macular CVI showed negative correlation with axial length (AL) and positive correlation with central corneal thickness (CCT). There were no significant differences in macular CVI or overall CVI between affected and healthy eyes, as well as in subgroup analysis of different stages of macular CVI. Following surgery, there was a significant decrease in CVI at 1 week postoperatively, followed by a gradual recovery to baseline levels over time. The observed changes in CVI may be attributed to factors such as air tamponade, pressure changes, and photoreceptor metabolism. This study provides insights into the pattern of CVI changes associated with MH surgery. The findings suggest that stage 4 MH is associated with decreased macular CVI in affected eyes. These results contribute to a better understanding of the effects of surgery on choroidal blood flow in MH patients.