Is there a relationship between the keratoconus and the peripapillary choroidal vasculature?

PURPOSE: To evaluate the peripapillary/parapapillary choroidal vascular parameters in the keratoconus (KC) and to determine the relationship between topography parameters and the peripapillary/parapapillary choroidal vascular parameters. METHOD: Ninety eyes of ninety patients with different stages of KC and 29 eyes of twenty-nine patients without KC were enrolled in the study. Patients with KC were divided into three groups according to the Amsler-Krumeich classification scale. The choroidal vasculature was assessed by choroidal vascular parameters [such as parapapillary choroidal microvascular density (pCMVd) and peripapillary choroidal vascularity index (pCVI)]. These parameters were also evaluated for correlation with other parameters. RESULT: The retinal nerve fibre layer thickness (RNFLT) of the superior-temporal area and the pCVI were decreased in group 3 compared to the control group (superiror-temporal RNFLT: 122.27 ± 21.43 vs 139.90 ± 21.7, p = 0.01 and pCVI: 67.04 ± 4.14 vs 69.99 ± 4.38, p = 0.04). The superior-temporal RNFLT was decreased in group 3 compared to group 2 (122.27 ± 21.43 vs 141.83 ± 25.58, p = 0.006). There was a negative correlation between pCVI and average simulated keratometry (mean sim K), but this association was weak (r = - 0.29 p = 0.001). CONCLUSION: This study demonstrated that there may be changes in pCVI in patients with grade 3 KC and that there may be an association between pCVI and mean sim K. As KC grade increases, pCVI may decrease. Furthermore, pCVI may have a negative correlation with mean sim K.

Peripapillary choroidal vascularity of paediatric myopic eyes with peripapillary hyperreflective ovoid mass-like structures.

PURPOSE: To assess the peripapillary choroidal vasculature in paediatric myopic patients with and without peripapillary hyperreflective ovoid mass-like structures (PHOMS). METHODS: This prospective study includes 60 eyes of 60 myopic (spherical equivalent [SE] <-1.00 dioptre [D]) patients with (n = 30) and without (n = 30) PHOMS (PHOMS [+] and PHOMS [-] groups, respectively), and 30 eyes of 30 age- and sex-matched emmetropic children (control group). Peripapillary choroidal parameters, including total choroidal (TCA), luminal (LA), and stromal areas (SA) and choroidal vascularity index (CVI) calculated from vertical and horizontal single-line enhanced depth imaging-optical coherence tomography scans centred on optic nerve head. RESULTS: Peripapillary retinal nerve fibre layer thicknesses were not different between the groups (p > 0.05). In the PHOMS (+) group, TCA, LA and SA were lower, and CVI was higher in all quadrants compared to the control (p < 0.05). However, only the mean TCA and LA in the inferior and nasal quadrants and the mean SA in the nasal quadrant were lower in PHOMS (+) than in PHOMS (-) (p < 0.05). In the PHOMS (-) group, higher CVI was observed in all quadrants except temporal compared to the control group. Although the mean CVI of the PHOMS (+) group was also higher than in the PHOMS (-) group, this difference was not statistically significant. CONCLUSION: This study indicates that choroidal parameters differ in paediatric myopic patients with PHOMS. Further studies with larger sample sizes are needed to understand the details of choroidal parameters in eyes with PHOMS.

Evaluation of Choroidal Structures in Children with Newly Diagnosed Type-1 Diabetes Mellitus.

Objectives: The objective of this study was to evaluate the subfoveal choroidal thickness (SFCT) and choroidal vascularity index (CVI) in children with newly diagnosed type 1 diabetes mellitus (T1DM). Methods: A total of 80 children (40 with T1DM and 40 healthy controls) were included in this cross-sectional study. Enhanced depth imaging optical coherence tomography (EDI-OCT) images of all participants were analyzed. The SFCT, total choroidal area (TCA), luminal area (LA), stromal area (SA), and CVI measurements were obtained from EDI-OCT images and compared between groups. The effects of HbA1c, fasting plasma glucose, and axial length measurements on choroidal measurements were investigated. Results: There was no significant difference between the groups according to TCA (0.84 [0.57-1.26] vs. 0.88 [0.65-1.16] mm2, p=0.745), LA (0.55 [0.41-0.79] vs. 0.59 [0.43-0.74] mm2, p=0.745), SA (0.27 [0.15-0.47] vs. 0.28 [0.15-0.47] mm2, p=0.935), and CVI (68.03 [66.5-70.5] vs. 67.75 [66.2-69.5] %, p=0.794), respectively. However, T1DM patients had thinner SFCT compared to control subjects (309.0 [327-489] and 398.5 [219-491], p<0.044). No correlation was found between HbA1c, fasting plasma glucose, axial length measurements, and SFCT, TCA, LA, SA, or CVI. Conclusion: Children with newly diagnosed T1DM have thinner SCFT in comparison to healthy children, however, no significant difference in CVI was observed between the groups. Long-term follow-up should be used to confirm the impact of the DM duration on CVI.

Quantifying ocular microcirculation in hypertension patients with carotid artery stenosis.

Background: Carotid artery stenosis (CAS) is one of the most common macrovascular complications of hypertension. The ophthalmic artery springs from the internal carotid artery; however, the effect of CAS on ocular microcirculation has not been quantified in hypertension patients. This study aimed to quantify ocular microcirculation metrics in hypertension with CAS (HCAS) patients and to explore the relationship between micro- and macroangiopathy in hypertension. Methods: All participants (community-based) underwent detailed assessments, including carotid ultrasonography, optical coherence tomography angiography (OCTA), and enhanced depth imaging (EDI)-OCT. CAS was diagnosed using carotid ultrasonography. Retinal microcirculation metrics, including vessel density (VD), skeleton density (SD), fractal dimension (FD), and foveal avascular zone (FAZ), were quantified using OCTA and ImageJ software. Choroidal microcirculation metrics, including subfoveal choroidal thickness (SFCT), luminal area (LA), and choroidal vascularity index (CVI), were quantified using EDI-OCT and ImageJ. Retinal vessel caliber metrics, including central retinal artery equivalent (CRAE), central retinal vein equivalent (CRVE), and artery/vein ratio (AVR), were calculated using revised formulas. The above metrics were compared among the HCAS group, hypertension with no CAS (HNCAS) group, and healthy control group. The mutual effects between ocular metrics and CAS were evaluated using regression analyses. Results: In a comparison of the HCAS vs. HNCAS groups, retinal metrics including VD, SD, FD, and choroidal metrics including CVI and LA were significantly decreased in the HCAS group (all p < 0.05); however, FAZ, SFCT, and retinal vessel caliber metrics including CRAE, CRVE, and AVR were comparable between groups (all p > 0.05). In a comparison of HNCAS and the healthy control group, VD, SD, and CRAE showed that AVR was significantly decreased in the HNCAS group (all p < 0.05); meanwhile, choroidal metrics were comparable between groups (all p > 0.05). Linear regression analyses showed that intima-media thickness (IMT) (p = 0.01) and peak systolic velocity (PSV) (p = 0.002) were negatively related to retinal VD in hypertension patients. Logistic regression analyses disclosed that older age (p < 0.001), smoking history (p = 0.002), lower VD (p = 0.04), SD (p = 0.02), and CVI (p < 0.001) were related to the presence of CAS in hypertension patients. Conclusion: CAS in hypertension-induced hypoperfusion in retinal and choroidal microcirculation and the decreased retinal VD and choroidal CVI were significantly associated with the presence of CAS in patients with hypertension, suggesting that hypertension macro- and microangiopathy were mutually affected and share the common pathophysiology. Furthermore, OCT could be a useful tool to assess hypertension patient's CAS risk profiles in a non-invasive way.

Exploring and identifying the imaging biomarkers for predicting anti-VEGF treatment response in polypoidal choroidal vasculopathy: a prospective multicenter study.

BACKGROUND: Polypoidal choroidal vasculopathy (PCV) is a hemorrhagic fundus disease that can lead to permanent vision loss. Predicting the treatment response to anti-VEGF monotherapy in PCV is consistently challenging. We aimed to conduct a prospective multicenter study to explore and identify the imaging biomarkers for predicting the anti-VEGF treatment response in PCV patients, establish predictive model, and undergo multicenter validation. METHODS: This prospective multicenter study utilized clinical characteristics and images of treatment naïve PCV patients from 15 ophthalmic centers nationwide to screen biomarkers, develop model, and validate its performance. Patients from Peking Union Medical College Hospital were randomly divided into a training set and an internal validation set. A nomogram was established by univariate, LASSO regression, and multivariate regression analysis. Patients from the other 14 centers served as an external test set. Area under the curve (AUC), sensitivity, specificity, and accuracy were calculated. Decision curve analysis (DCA) and clinical impact curve (CIC) were utilized to evaluate the practical utility in clinical decision-making. FINDINGS: The eye distribution for the training set, internal validation set, and external test set were 66, 31, and 71, respectively. The 'Good responder' exhibited a thinner subfoveal choroidal thickness (SFCT) (230.67 ± 61.96 vs. 314.42 ± 88.00 µm, p < 0.001), lower choroidal vascularity index (CVI) (0.31 ± 0.08 vs. 0.36 ± 0.05, p = 0.006), fewer choroidal vascular hyperpermeability (CVH) (31.0 vs. 62.2%, p = 0.012), and more intraretinal fluid (IRF) (58.6 vs. 29.7%, p = 0.018). SFCT (OR 0.990; 95% CI 0.981-0.999; p = 0.033) and CVI (OR 0.844; 95% CI 0.732-0.971; p = 0.018) were ultimately included as the optimal predictive biomarkers and presented in the form of a nomogram. The model demonstrated AUC of 0.837 (95% CI 0.738-0.936), 0.891 (95% CI 0.765-1.000), and 0.901 (95% CI 0.824-0.978) for predicting 'Good responder' in the training set, internal validation set, and external test set, respectively, with excellent sensitivity, specificity, and practical utility. INTERPRETATION: Thinner SFCT and lower CVI can serve as imaging biomarkers for predicting good treatment response to anti-VEGF monotherapy in PCV patients. The nomogram based on these biomarkers exhibited satisfactory performances.

Choroidal and retinal vascular changes in HLA-B27-associated anterior uveitis.

PURPOSE: To quantitatively analyze choroidal and retinal vascular changes in HLA-B27-associated anterior uveitis. STUDY DESIGN: A retrospective study. METHODS: Medical records of 51 eyes with unilateral HLA-B27-associated anterior uveitis, their fellow eyes and 47 sex and age-matched healthy eyes were retrospectively reviewed. Their choroidal and retinal vasculature were analyzed using swept-source (SS) optical coherence tomography (OCT) and OCT angiography (OCTA) scans. RESULTS: Deep capillary plexus (DCP) vessel density (VD) (p < 0.001), choroidal vascularity index (CVI) (p = 0.012), and choriocapillary flow deficit (CCFD) (p < 0.001) of uveitic and fellow eye group were significantly higher than those of control group. On the contrary, superficial capillary plexus (SCP) VD (p < 0.001) of uveitic and fellow eye group were significantly lower than of control group. The vascular parameters of uveitis and fellow eye group showed no significant difference between uveitic and resolution period. CONCLUSION: Certain choroidal and retinal vascular parameters were significantly changed in both HLA-B27-associated anterior uveitis without posterior segment involvement and the quiet fellow eyes, suggesting their possible effects as a systemic inflammatory disorder.

Investigation of choroidal thickness and choroidal vascularity index in ocular rosacea patients according to skin subtypes.

BACKGROUND: To compare the choroidal thickness (CT) and choroidal vascularity index (CVI) values in ocular rosacea (OR) patients across skin subtypes of the disease and healthy controls. METHODS: This prospective study included 90 eyes of 90 mild-moderate OR patients with different skin subtypes (30 phymatous, 30 papulopustular and 30 erythematotelangiectatic) and 30 eyes of 30 age-gender matched healthy volunteers. After obtaining the enhanced depth imaging optical coherence tomography images, the CT was measured at subfoveal, 1500 µm nasal and 1500 µm temporal to the fovea, and the CVI was calculated using Image J software in the subfoveal, nasal and temporal areas. RESULTS: There was no CT significant difference between OR patients and healthy controls in all regions (p > 0.05). CVI values of OR patients were found to be significantly lower in the subfoveal, nasal and temporal regions compared to healthy controls (p = 0.02, p = 0.01, p = 0.01, respectively). No CT difference was detected between the subtypes and healthy controls in all regions (p > 0.05). Subfoveal-CVI was significantly lower in the phymatous subtype than the other subtypes and controls (p < 0.05), while nasal and temporal-CVI were significantly lower in the phymatous and papulopustular subtypes than the erythematotelangiectatic subtype and controls. CONCLUSION: Our study demonstrated no difference between rosacea skin types and healthy controls in terms of CT. Phymatous and papulopustular subtypes were more likely to be affected by chronic inflammation with having lower CVI in most of the regions. Further studies are needed to investigate the association of inflammatory factors with CVI in OR.

Choroidal Vascularity Index and Subfoveal Choroidal Thickness in Rheumatoid Arthritis Assessed with Enhanced-Depth Imaging Optical Coherence Tomography.

PURPOSE: To evaluate the effects of rheumatoid arthritis (RA) on choroidal vascularity index (CVI) and subfoveal choroidal thickness (SFCT). METHODS: The study included 56 eyes of 56 rheumatoid arthritis patients and 65 eyes of 65 age- and sex-matched healthy normal participants. CVIs of all participants were measured by transferring enhanced depth imaging optical coherence tomography (EDI-OCT) images to the image J program that is software used for image binarization and compared between the 2 groups. SFCT, central macular thickness (CMT) and optic disc parameters of all participants were measured with spectral domain OCT and compared. RESULTS: The mean CVI values of the RA and control groups were 65.9 ± 1.52 and 68.56 ± 1.62, respectively, and were significantly lower in the RA group (p = 0.001). Mean SFCT values of the RA and control groups were 290.11 ± 15.18 and 332.88 ± 11.04, respectively, and SFCT was significantly lower in the RA group (p = 0.001). RA patients have thin SFCT and low CVI. There was no significant difference between the two groups in terms of CMT and optic disc parameters. CONCLUSION: RA patients have lower CVI and thinner SFCT than healthy participants.

Factors affecting choroidal circulation parameters in 4-14-year-old Chinese children measured by SS-OCT/OCTA.

PURPOSE: To measure the choroidal circulatory parameters Han Chinese children aged 4-14 years from Southwest China, and to explore the relationships between these parameters and age, axial length (AL), and choroidal thickness (ChT). METHODS: 284 eyes from 142 subjects were included in this cross-sectional study. All participants underwent cycloplegic refraction and IOLMaster500 examination. Swept-source optical coherence tomography (SS-OCT) was used to measure submacular choroidal thickness, choroidal vascular volume (CVV), choroidal stromal volume (CSV), choroidal vascularity index (CVI), and CVV/CSV ratio. RESULTS: In this population, the mean CVV was 2.92 ± 0.55 mm3, CSV was 4.69 ± 0.68 mm3, CVI was 38.22 ± 2.46 %, and CVV/CSV ratio was 62.11 ± 6.44 %. Multivariable regression analyses showed that both CVV and CSV were negatively correlated with AL (both P < 0.001) and positively correlated with ChT (both P < 0.001), while age showed no significant correlation with them (both P > 0.05). However, the correlations between CVI and age were not uniform rectilinear. Among participants aged ≤8 years, CVI showed no correlation with age (P > 0.05), while among those aged >8 years, it was positively correlated with age (P < 0.01). CVV/CSV ratio was positively correlated with ChT and age (both P < 0.01). CONCLUSION: After the age of 8, age was positively correlated with CVI. ChT was well correlated with CVI. Longer AL and thinner ChT were associated with reduced CVV and CSV, with CVV decreasing more rapidly than CSV.

Choroidal vascularity index in patients with computer vision syndrome combined with accommodative lead.

BACKGROUND: This study aimed to investigate the choroidal vascularity index (CVI) in patients with computer vision syndrome (CVS) combined with accommodative lead. METHODS: This retrospective case-control study enrolled patients diagnosed with CVS and accommodative lead at University-Town Hospital of Chongqing Medical University between July 2022 and May 2023. The control group included individuals without any ocular diseases. Ophthalmic assessments included basic visual acuity, refraction, ocular biometric parameters, and CVI. RESULTS: A total of 85 participants were included in the study, with 45 in the CVS group and 40 in the control group. The central corneal thickness of CVS group was found to be significantly thinner compared to the control group in both the right eye (532.40±30.93 vs. 545.78±19.99 µm, P = 0.019) and left eye (533.96±29.57 vs. 547.56±20.39, P = 0.014). In comparison to the control group, the CVS group exhibited lower CVI in the superior (0.40±0.08 vs. 0.43±0.09, P = 0.001), temporal (0.40±0.08 vs. 0.44±0.10, P < 0.001), inferior (0.41±0.08 vs. 0.46±0.08, P < 0.001), and nasal (0.41±0.08 vs. 0.44±0.08, P = 0.001) quadrants. Similar differences were observed in all four quadrants within the 1-3 mm radius, and in the temporal (P = 0.004) and inferior (P = 0.002) quadrants within the 1-6 mm and 3-6 mm radii (all P < 0.05). CONCLUSION: Compared to individuals without ocular issues, patients with CVS and accommodative lead were found to have thinner corneal central thickness and lower CVI.

Detecting early changes in choroidal vascularity and thickness using optical coherence tomography in patients with corneal crosslinking for keratoconus.

AIM: To investigate changes in choroidal thickness and vascularity in keratoconus patients treated with corneal crosslinking. METHODS: This study evaluated 28 eyes of 22 patients with keratoconus who underwent corneal crosslinking. The choroidal thicknesses were evaluated on enhanced depth imaging optical coherence tomography at the preoperative and postoperative 3d, 1, and 3mo. Choroidal thickness in the four cardinal quadrants and the fovea were evaluated. The choroidal vascularity index was also calculated. RESULTS: There was no significant difference in central choroidal thickness between the preoperative and postoperative 3d, 1mo (P>0.05). There was a significant increase in the 3mo (P=0.034) and a significant decrease in the horizontal choroidal vascularity index on the postoperative 3d (P=0.014), there was no statistically significant change in vertical axes and other visits in horizontal sections (P>0.05). CONCLUSION: This study sheds light on choroidal changes in postoperative corneal crosslinking for keratoconus. While it suggests the procedure's relative safety for submacular choroid, more extensive research is necessary to confirm these findings and their clinical significance.

Quantitative assessment of intervortex anastomosis in central serous chorioretinopathy and fellow eyes: Does the size of anastomotic vessels matter for the diagnosis?

PURPOSE: To evaluate the frequency and size of intervortex anastomosis at the posterior pole on en-face spectral domain optical coherence tomography (SD-OCT) images in central serous chorioretinopathy (CSC) cases and their fellow eyes and its associations with choroidal morphology. METHODS: Sixty-five treatment-naive eyes of 65 patients with CSC, 65 fellow eyes, and 55 eyes of healthy age-matched participants were included. The presence of intervortex anastomosis at the watershed zone and asymmetry of the choroidal vessels between the superior and inferior macula were evaluated using 6 × 6 mm en-face SD-OCT. The diameter of the widest Haller vessel and the diameter of the widest anastomotic Haller vessel passing through the watershed zone were measured on en-face SD-OCT images. The choroidal vascularity index (CVI) was assessed using ImageJ software. RESULTS: Intervortex vein anastomosis on the horizontal watershed zone was detected in 75.4% diseased eyes, 61.5% in fellow eyes, and 36.4% in healthy age-matched controls (p < 0.001). The mean CVI was significantly higher in both diseased (74.3 ± 2.3%) and fellow (73.8 ± 2.2%) eyes of CSC cases than in healthy controls (72.5 ± 2.3%) (p = 0.002, p = 0.013, respectively). In the cases with intervortex vein anastomosis, the diameter of the widest anastomotic Haller vessel passing through the watershed zone was 0.40 ± 0.10 mm in diseased eyes, 0.35 ± 0.11 mm in fellow eyes, and 0.30 ± 0.09 mm in healthy age-matched controls (p = 0.001). CONCLUSIONS: Intervortex anastomosis might be seen as a variation in normal eyes, however, its frequency and the size of anastomotic vessels are significant higher in not only CSC but also in fellow eyes.

Evaluation of Choroidal Thickness and Choroidal Vascularity Index in Patients with Rheumatoid Arthritis.

PURPOSE: To evaluate the choroidal vascularity index and choroidal thickness in patients with rheumatoid arthritis. METHOD: This study is a case control study. Our study consists of a total of two groups, with 32 individuals diagnosed with rheumatoid arthritis (RA) and 32 healthy volunteers. The thickness of the subfoveal choroid was measured from the 500 micron (µm), 1000 µm, 1500 µm nasal aspect of the fovea, and 500µm, 1000µm, 1500 µm temporal and subfoveal thickness of the fovea. ImageJ version 1.53i (National Institutes of Health, Bethesda, MD, USA) from open access was used for choroidal vascular index calculation. RESULTS: The mean age (p = 0.064) and gender distribution (p = 0.522) were not statistically different between these two groups. There was no difference between the groups in terms of visual acuity (p = 0.060), intraocular pressures (p=0.056), refractive errors (p = 0.418), and axial lengths (p = 0.280). Temporal 500 µm CT (p = 0.038), temporal 1000 µm CT (p = 0.010), and temporal 1500 µm CT (p = 0.005) differed significantly between the groups. The luminal area was significantly different between the RA group (842.71 ± 192.77) and the control group (957.78 ± 230.83) (p = 0.034). The choroidal vascularity index showed a significant difference between the RA group (64.99 ± 4.71) and the control group (67.34 ± 3.40) (p = 0.026). A significant difference was observed between the seronegative RA and the control group with temporal 1500 µm CT (p = 0.030), temporal 1000 µm CT (p = 0.023), and luminal area (p = 0.034). CONCLUSION: We demonstrated thinning in CT and decreased CVI for the first time in RA patients by comparing it with the control group.

Choroidal manifestations of non-ocular sarcoidosis: an enhanced depth imaging OCT study.

BACKGROUND: Although choroidal thickening was reported as a sign of active inflammation in ocular sarcoidosis, there has been no research on the choroidal changes in non-ocular sarcoidosis (defined as systemic sarcoidosis without overt clinical signs of ocular involvement). Therefore, this study aimed to investigate choroidal structural changes in patients with non-ocular sarcoidosis. METHODS: This retrospective case-control study was conducted at Asan Medical Center, a tertiary referral center. We evaluated 30 eyes with non-ocular sarcoidosis and their age- and spherical equivalent-matched healthy control eyes. The subfoveal choroidal thickness, area ratio (Sattler layer-choriocapillaris complex [SLCC] area to Haller layer [HL] area), and choroidal vascularity index (CVI, luminal area to choroidal area) were analyzed using enhanced depth imaging in optical coherence tomography. Systemic and ocular factors associated with the choroidal thickness were investigated. RESULTS: Compared with the healthy control group, the non-ocular sarcoidosis group had significantly thicker subfoveal choroid (total and all sublayers [SLCC and HL]) and lower area ratio. There were no significant differences in the CVIs at all sublayers between groups. In the non-ocular sarcoidosis group, eyes under oral steroid treatment had thinner choroid than eyes under observation. In the control group, eyes with older age and more myopic spherical equivalent had thinner choroidal thickness. CONCLUSION: Total and all sublayers of the subfoveal choroid were significantly thicker without significant vascularity changes in non-ocular sarcoidosis eyes than in healthy control eyes. The degree of choroidal thickening was disproportionally greater at HL than at SLCC. These characteristic choroidal changes may be the subclinical manifestations in non-ocular sarcoidosis.

Evaluation of Choroidal Structure in Type 1 Macular Neovascularization Using Different Optical Coherence Tomography Analyses: Scale Bar and Binarization.

BACKGROUND: Macular neovascularization (MNV) has been evaluated by optical coherence tomography (OCT) imaging using various approaches. However, few studies have examined their differences. This study analyzed type 1 MNV with a combination of two approaches: scale bar and binarization. METHODS: We enrolled 84 patients with untreated type 1 MNV. We measured choroidal parameters using a scale bar and defined the ratios of superficial choroidal thickness to choroidal vessel diameter (SV ratios). We also used binarization and calculated the ratios of the luminal to the choroidal area (LC ratios) in two directions (horizontal and vertical). RESULTS: Fifty-one patients (61%) were classified as having polyps. SV ratios in the group with polyps were significantly lower than in the group without (p < 0.001). The receiver operating characteristic (ROC) curve showed that the SV ratio was predictive of polyps (AUC 0.733, 95% CI: 0.621-0.844). In patients without polyps, horizontal LC ratios were significantly higher in a subgroup with subretinal fluid than in those without (p = 0.047). The ROC curve showed that the LC ratio was predictive of subretinal fluid (AUC 0.722, 95% CI: 0.517-0.926). CONCLUSION: The SV ratio reflects the MNV disease type, whereas the LC ratio reflects MNV disease activity. Establishing cut-off values for each ratio may be useful for MNV diagnosis.

Three-dimensional choroidal vascularity index and choroidal thickness in fellow eyes of acute and chronic primary angle-closure using swept-source optical coherence tomography.

AIM: To compare the three-dimensional choroidal vascularity index (CVI) and choroidal thickness between fellow eyes of acute primary angle-closure (F-APAC) and chronic primary angle-closure glaucoma (F-CPACG) and the eyes of normal controls. METHODS: This study included 37 patients with unilateral APAC, 37 with asymmetric CPACG without prior treatment, and 36 healthy participants. Using swept-source optical coherence tomography (SS-OCT), the macular and peripapillary choroidal thickness and three-dimensional CVI were measured and compared globally and sectorally. Pearson's correlation analysis and multivariate regression models were used to evaluate choroidal thickness or CVI with related factors. RESULTS: The mean subfoveal CVIs were 0.35±0.10, 0.33±0.09, and 0.29±0.04, and the mean subfoveal choroidal thickness were 315.62±52.92, 306.22±59.29, and 262.69±45.55 µm in the F-APAC, F-CPACG, and normal groups, respectively. All macular sectors showed significantly higher CVIs and choroidal thickness in the F-APAC and F-CPACG eyes than in the normal eyes (P<0.05), while there were no significant differences between the F-APAC and F-CPACG eyes. In the peripapillary region, the mean overall CVIs were 0.21±0.08, 0.20±0.08, and 0.19±0.05, and the mean overall choroidal thickness were 180.45±54.18, 174.82±50.67, and 176.18±37.94 µm in the F-APAC, F-CPACG, and normal groups, respectively. There were no significant differences between any of the two groups in all peripapillary sectors. Younger age, shorter axial length, and the F-APAC or F-CPACG diagnosis were significantly associated with higher subfoveal CVI and thicker subfoveal choroidal thickness (P<0.05). CONCLUSION: The fellow eyes of unilateral APAC or asymmetric CPACG have higher macular CVI and choroidal thickness than those of the normal controls. Neither CVI nor choroidal thickness can distinguish between eyes predisposed to APAC or CPACG. A thicker choroid with a higher vascular volume may play a role in the pathogenesis of primary angle-closure glaucoma.

Association between choroidopathy and photoreceptors during the early stage of diabetic retinopathy: a cross-sectional study.

PURPOSE: To explore the role of choroidopathy in diabetic retinopathy (DR) by investigating the correlation between alterations of choroidal vessel and photoreceptors during the early stage of DR. METHODS: We performed a cross-sectional comparison of diabetic patients without DR (NDR group; n=16) and those with mild nonproliferative diabetic retinopathy (NPDR group; n=39). Optical coherence tomography (OCT) images of choroidal vessel alterations and photoreceptor structures were evaluated using the choroidal vascularity index (CVI) and adjusted ellipsoid zone (EZ) reflectivity, respectively. To evaluate the function of cone photoreceptors, the fundamental, harmonic amplitudes, the parameters S and Rmp3 were calculated from the electroretinogram (ERG). These factors were compared between groups. The correlation between the CVI and parameters describing the function and structure of the photoreceptors was evaluated. RESULTS: The significant decrease was observed in the CVI in the NPDR group compared to the NDR group (0.67 ± 0.04 vs. 0.70 ± 0.06; p = 0.028), but not in the adjusted EZ reflectivity or ERG parameters. In NPDR group and merging the 2 groups, CVI was moderately positively correlated with the fundamental amplitude obtained by the flicker ERG (NPDR only: r = 0.506; p = 0.001; merge the 2 groups: r = 0.423; p = 0.001), which was regulated by the response of the cone photoreceptors. The CVI was positively and moderately correlated with the logS (NPDR only: r = 0.462; p = 0.003; merge the 2 groups: r = 0.355; p = 0.008), indicating the sensitivity of cone cell light transduction. CONCLUSION: Compared to eyes without DR, CVI decreased representing choroidal vascular changes in eyes with mild NPDR. These changes may be related to the functional impairment of cone photoreceptors, especially phototransduction sensitivity, as the DR develops.

Comparison of choroidal structural changes between term and preterm children with and without retinopathy of prematurity.

PURPOSE: To evaluate the effects of prematurity and retinopathy of prematurity (ROP) treatment on choroidal structure using the image binarization method and compare with term children. METHODS: Children aged 6-11 years were included in this prospective case-control study. There were 36 (72 eyes) term children and 52 (103 eyes) preterm children included in the study. Subfoveal choroidal thickness (SFCT) and choroidal thickness (CT) at 500, 1500, and 2500 µm temporal and nasal from the fovea were measured. Images were binarized using the Image J program. The choroidal vascularity index (CVI) was calculated by dividing the luminal area by the total subfoveal choroidal area. RESULTS: There was no significant difference in SCFT between children born at term (290.44±57.617 µm) and preterm (288±69.270 µm) (p = 0.800). CVI was found to be significantly higher in term children (71.90±2.60 %) than in preterm children (69.58±2.72 %) (p<0.001), and the difference was also significant when compared to preterm children without ROP (p = 0.033). In the preterm subgroups, although CVI was higher in preterm children without ROP (70.42±2.24 %) than in those with spontaneous regression (69.34±3.30 %) and those treated with laser photocoagulation (68.91±2.35 %), there was no significant difference (p = 0.330, p = 0.089 respectively). CVI was similar between children with spontaneous regression and those treated with laser photocoagulation (p = 0.909). CVI and logMAR best corrected visual acuity (BCVA) were inversely correlated (r=-0.295 p<0.001). CONCLUSION: Reduced CVI in preterm children indicates that prematurity is related to the choroid. Choroidal vascularity index appears to be a more reliable marker than CT for evaluating the relationship between choroid and ROP.

Choroidal Perfusion Changes After Vitrectomy for Myopic Traction Maculopathy.

BACKGROUND: The choroidal vasculature supplies the outer retina and is altered in many retinal diseases, including myopic traction maculopathy (MTM). Choroid health is typically assessed by measuring the choroidal thickness; however, this method has substantial limitations. The choroidal vascularity index (CVI) was recently introduced to provide quantitative information on the vascular flow in the choroid. This index has been evaluated in a wide range of diseases but has not been extensively used to characterize MTM. AIM: This study aimed to investigate the CVI across different stages of MTM and the influence of macular surgery on choroidal perfusion markers in different surgically resolved MTM stages. METHODS: Eighteen healthy myopic eyes in the control group and forty-six MTM eyes in the surgical group were evaluated using enhanced optical coherence tomography (OCT) imaging. Binarized OCT images were processed to obtain the luminal choroidal area (LCA) and stromal choroidal area (SCA), which were used to calculate CVI in the form of a percentage ratio. CVI data were collected at baseline, one and four months postoperatively, and at the final clinical visit. MTM eyes were divided into four stages based on disease severity. The choriocapillaris flow area (CFA) and central subfield thickness (CSFT) were measured along side the CVI. RESULTS: No significant differences were observed between the two groups at baseline, except for visual acuity (p < 0.0001). Surgery significantly improved vision at all postoperative time points (p < 0.0001). At baseline, there were no significant differences in CVI, CFA, or CSFT scores between the control and surgical groups. However, all three measurements were lower at the final visit in the surgical group (p ≤0.0001). No significant differences were found in any of the parameters among the four stages of MTM (p > 0.05). Ultimately, correlation and multivariate linear regression analyses did not reveal any significant association between CVI and visual acuity. CONCLUSIONS: This study did not find significant preoperative differences in CVI between healthy myopic eyes and eyes with MTM. However, the postoperative CVI and CFA values were significantly lower than those of the control eyes. Thus, CVI may not be a good biomarker for surgical outcomes, as the correlation between CVI and visual acuity was not statistically significant.The CVI and CFA decreased after surgery, providing evidence of choroidal changes after surgical management.

Quantitative analysis of deep learning-based denoising model efficacy on optical coherence tomography images with different noise levels.

BACKGROUND: To quantitatively evaluate the effectiveness of the Noise2Noise (N2N) model, a deep learning (DL)-based noise reduction algorithm, on enhanced depth imaging-optical coherence tomography (EDI-OCT) images with different noise levels. METHODS: The study included 30 subfoveal EDI-OCT images averaged with 100 frames from 30 healthy participants. Artificial Gaussian noise at 25.00, 50.00, and 75.00 standard deviations were added to the averaged (original) images, and the images were grouped as 25N, 50N, and 75N. Afterward, noise-added images were denoised with the N2N model and grouped as 25dN, 50dN, and 75dN, according to previous noise levels. The choroidal vascularity index (CVI) and deep choroidal contrast-to-noise ratio (CNR) were calculated for all images, and noise-added and denoised images were compared with the original images. The structural similarity of the noise-added and denoised images to the original images was assessed by the Multi-Scale Structural Similarity Index (MS-SSI). RESULTS: The CVI and CNR parameters of the original images (68.08 ± 2.47 %, and 9.71 ± 2.80) did not differ from the only 25dN images (67.97 ± 2.34 % and 8.50 ± 2.43) (p:1.000, and p:0.062, respectively). Noise reduction improved the MS-SSI at each noise level (p < 0.001). However, the highest MS-SSI was achieved in 25dN images. CONCLUSIONS: The DL-based N2N denoising model can be used effectively for images with low noise levels, but at increasing noise levels, this model may be insufficient to provide both the original structural features of the choroid and structural similarity to the original image.