Analysis of choroidal vascularity index distribution and influencing factors in normal children / 中华实验眼科杂志

Objective:To evaluate the distribution characteristics of choroidal vascularity index (CVI) in macula among normal children using swept-source optical coherence tomography (SS-OCT), and to investigate the influencing factors.Methods:A cross-sectional study was conducted.Sixty-three children aged 6 to 12 years were enrolled in The First Affiliated Hospital of Zhengzhou University from May 2021 to November 2021.Spherical equivalent refraction, axial length (AL) and other ocular biological parameters were measured.Macula-centered CVI and choroidal thickness (ChT) were measured by SS-OCT angiography.According to the ETDRS partition, the obtained image was divided into macular central fovea (0-1 mm diameter), inner ring (1-3 mm diameter) and outer ring (3-6 mm diameter) zones.Data from the right eye were selected for statistical analysis.CVI in the three rings and four zones (superior, temporal, inferior and nasal zones) of the inner and outer rings were compared.Univariate and multiple linear regression analyses were used to analyze the correlation between CVI and sex, AL, anterior chamber depth (ACD), ChT and pupil diameter.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of The First Affiliated Hospital of Zhengzhou University (No.2021-KY-0399-003). Written informed consent was obtained from each guardian.Results:The average CVI in the macular central fovea, inner ring and outer ring were 0.35±0.12, 0.32±0.10 and 0.27±0.08, respectively, with a significant difference ( F=10.96, P<0.001), and significant differences in CVI were found in pairwise comparisons of the three ring zones (all at P<0.05). Significant differences in CVI were found among superior, temporal, inferior and nasal zones in inner and outer rings ( Fring=11.60, P=0.001; Fzone=12.02, P<0.05). The CVI was smaller in superior and nasal zones in inner ring than in temporal zone, greater in superior, temporal and inferior zones in outer ring than in nasal zone, smaller in superior zone of outer ring than that of the inner ring, and the differences were statistically significant (all at P<0.001). The single factor linear regression analysis showed that ChT in the fovea, inner ring and outer ring were the influencing factors of CVI in the three ring zones (all at β=0.001, P<0.001). Pupil diameter ( β=0.034, P=0.038; β=0.040, P=0.003; β=0.024, P=0.011) and ACD ( β=0.097, P=0.034; β=0.097, P=0.013; β=0.061, P=0.032) were the influencing factors of CVI in fovea, inner ring and outer ring.After multiple linear regression analysis, the regression equations were established as follows: CVI in the macular fovea=0.001×ChT in the macular fovea + 0.001×ChT in the inner ring+ 0.001×ChT in the outer ring-0.301 ( R2=0.514, F=6.875, P<0.001); CVI in the inner ring=0.001×ChT in the macular fovea+ 0.001×ChT in the inner ring+ 0.001×ChT in the outer ring+ 0.088×AL-0.307 ( R2=0.603, F=9.870, P<0.001); CVI in the outer ring=0.001×ChT in the macular fovea+ 0.001×ChT in the inner ring+ 0.001×ChT in the outer ring-0.135 ( R2=0.601, F=9.781, P<0.001). Conclusions:In children aged 6-12 years old, the CVI is higher in the macular central fovea than in inner and outer rings, and the CVI in nasal zone is the smallest in both inner and outer rings.The thicker the ChT, the higher the CVI in all zones in the macular area; the deeper the anterior chamber, the higher the CVI in the inner ring.

Evaluation of choroidal vascularity index and subfoveal choroidal thickness in eyes with chronic central serous chorioretinopathy and their normal fellow eyes / 中华实验眼科杂志

Objective:To observe the choroidal vascular changes of chronic central serous chorioretinopathy (cCSC), and analyze their correlations with central macular thickness (CMT).Methods:A cross-sectional study was adopted.Seventy-six eyes of 38 patients with monocular cCSC who were treated in Renmin Hospital of Wuhan University from March 2018 to December 2019 were enrolled, and 30 eyes of 30 normal control matched with age, gender, and spherical equivalent (SE) were included.Choroidal images of all subjects, and the CMT, subfoveal choroidal thickness (SFCT), choroidal vascularity index (CVI), total choroidal area (TCA), choroidal stromal area (SA), and choroidal luminal area (LA) were measured by Heidelberg enhanced depth imaging optical coherence tomography.The differences in SFCT, LA, SA, TCA, CMT and CVI between the cCSC eye, fellow eye and normal eye, as well as the correlation between SFCT and CVI, SFCT and CMT, and CVI and CMT were analyzed.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Renmin Hospital of Wuhan University (No.WDRY2020-K234).Results:The CVI and the SFCT of the cCSC eyes, fellow eyes and normal eyes were (71.67±5.60)% and 483.82(409.01, 550.87)μm, (68.33±3.85)% and 444.66(351.25, 505.15)μm, (64.70±1.88)% and 373.46(327.98, 405.48)μm, respectively.The CMT, SFCT, TCA, LA, CVI in cCSC eyes were significantly higher than those in the contralateral eyes and normal control eyes, while SFCT, TCA, LA, CVI in the contralateral eyes were higher than those in normal control eyes (all at P<0.05). Pairwise comparison among the three groups showed no significant difference in SA (all at P>0.05). Correlation analysis showed that in cCSC eyes, SFCT was strongly positively correlated with CVI ( rs=0.703, P<0.001), and there was no correlation between CMT and SFCT ( rs=0.181, P=0.278), or CMT and CVI ( r=0.231, P=0.164). Conclusions:The SFCT and CVI are higher in cCSC and the fellow eyes compared with normal eyes, and the choroidal vessels are significantly dilated in cCSC patients.The SFCT and CVI of the cCSC eye are slightly higher in comparison with the fellow eye.CMT is not correlated with SFCT or CVI in cCSC eyes.

Early changes of retinal and choroidal microvascular structure in hypertensive patients / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To explore the feasibility of swept source optical coherence tomography angiography(SS-OCTA)in evaluating early retinal and choroidal microcirculation changes in patients with hypertension.METHODS:Prospective clinical study. A total of 27 patients with grade 2 or 3 essential hypertension(hypertension group)diagnosed in the Department of Cardiology of Xi'an First Hospital from July to November 2022 were included in the study. There were 14 males and 13 females. The mean age was(57.11±3.36)years. During the same period, 27 age- and sex-matched normal people without a history of hypertension were selected as the control group, including 12 males and 15 females. The average age was(55.74±2.95)years old. All patients underwent BCVA(LogMAR), intraocular pressure, axial length, slit lamp examination, fundus color photography and SS-OCTA examination. SS-OCTA was used to scan the macular area of the right eye in the range of 6×6 mm. The retina and choroid were divided into three concentric circles with diameters of 0-1 mm, 1-3 mm and 3-6 mm around the fovea according to ETDRS. Macular vessel density(VD), perfusion area(PA), retinal thickness(CMT), choroidal thickness(CT), choroidal vessel volume(CVV)and choroidal vasculr index(CVI)of the superficial capillary plexus(SCP)and the deep capillary plexus(DCP)in the macular area of 0-1 mm, 1-3 mm and 3-6 mm were analyzed and recorded. The changes in VD, PA, CMT, CT, CVV and CVI were compared between the two groups. Independent sample t-test was used to compare VD, PA, CMT and CVI between the two groups; CT, CVV and LogMAR visual acuity were analyzed by Wilcoxon signed rank test of independent samples.RESULTS:Compared with the control group, the hypertensive group had significantly lower VD in the macular area 0-3 mm(0-1 mm, t=-3.144; 1-3 mm, t=-3.611, P&#x003C;0.05). VD in the area of 3-6 mm showed a tendency to increase compared with the control group(t=1.715, P&#x003E;0.05). The CMT in the 0-1mm area of the macular area in the hypertension group was lower than that in the control group(t=-2.624, P&#x003C;0.05). There was no significant difference in CT, CVV and CVI between the two groups(P&#x003E;0.05).CONCLUSION:The VD of DCP in the 0-3 mm area and the CMT in the 0-1 mm area are decreased in hypertensive patients. There were no significant differences in CT, CVV and CVI between the two groups. VD and CMT in macular DCP may be used as indicators to evaluate the early changes of retinal and choroidal microcirculation in hypertensive patients.

How does anisometropia affect the choroidal vascularity index?

Purpose: To investigate the choroidal vascularity index (CVI) and morphological features of the choroid in anisometropic amblyopia. Methods: In this prospective cross?sectional study, 39 patients with unilateral anisometropic amblyopic patients and 33 eyes of 33 healthy control participants were involved. These participants were examined in terms of axial length (AL), spherical equivalent (SE), central macular thickness (CMT), choroidal thickness (CT), total choroidal area (TCA), luminal area (LA), stromal area (SA), LA/SA ratio, and CVI. All parameters were compared between amblyopic eyes, healthy fellow eyes, and healthy control eyes. The Shapiro–Wilk tests, Chi?square test, the paired t?test, Wilcoxon signed?rank test, Mann–Whitney U test, Kruskal–Wallis test, and Pearson/Spearman correlation tests were used. Results: In the hyperopic patients; SE, subfoveal CT, nasal CT, temporal CT, TCA, LA, SA, and CMT were greater in amblyopic eyes than in healthy fellow eyes and control eyes (P < 0.001, P < 0.001, P < 0.001, P < 0.001, P < 0.001, P < 0.001, and P < 0.001, respectively), and CVI, LA/SA ratio, and AL were smaller in amblyopic eyes than in healthy fellow eyes and control eyes ([P < 0.001, P = 0.006], P < 0.001, and P < 0.001, respectively). In the myopic patients, subfoveal CT, nasal CT, temporal CT, TCA, LA, SA values were statistically smaller in amblyopic eyes than in healthy eyes and control eyes ([P < 0.001, P = 0.002), [P = 0.004, P = 0.012], [P = 0.012, P = 0.032], [P < 0.001, P = 0.013], [P < 0.001, P = 0.024], and [P < 0.001, P = 0.047], respectively). The differences in the AL and choroidal parameters were due to myopia and hyperopia. Conclusion: The choroidal structural parameters of the amblyopic eyes were different from that of the healthy eyes.

Parapapillary atrophy, choroidal vascularity index and their correlation in different degrees of myopia / 中华眼底病杂志

Objective:To observe the peripapillary atrophy (PPA) and peripapillary choroidal vascularity index (CVI) in patients with different degrees of myopia and to analyze their correlations.Methods:A cross-sectional clinical study. From September 2021 to December 2021, 281 mypoic patients of 281 eyes treated in Eye Hospital of Wenzhou Medical University at Hangzhou were included in this study, and the right eye was used as the treated eye. There were 135 eyes in 135 males and 146 eyes in 146 females. The age was 28.18±5.78 years. The spherical equivalent refraction (SE) was -5.13±2.33 D. The patients were divided into three groups: low myopia group (group A, -3.00 D <SE≤-0.50 D), moderate myopia group (group B, -6.00 D≤SE≤-3.00 D);high myopia group (group C, SE<-6.00 D). The spherical equivalent refraction was statistically different among the three groups ( H=241.353, P<0.05). All of the affected eyes were examined by swept-source optical coherence tomography. Combined with B-scan image,assessment and area measurement of β area, γ area (β-PPA and γ-PPA) were carried out on the en-face image. After binarization of the collected images, the nasal, superior, temporal and inferior CVI of the optic disc were calculated. For comparison between groups, one-way ANOVA was used for continuous variables with normal distribution, Kruskal-Wallis test was used for continuous variables with abnormal distribution, and categorical variables were used χ2 inspection. Linear regression analysis was used for the relationship between β-PPA and γ-PPA area and peripapillary CVI of different regions. Linear regression analysis was used to evaluate the relationships between the area of peripapillary atrophy and peripapillary choroidal vascularity index in different regions. Results:There was no statistical difference in the incidence of β-PPA among the three groups ( χ2=4.672, P=0.097). The incidence of γ-PPA in group A was lower than that in group B anc C, and the difference was statistically different ( χ2=33.053, P<0.001), in which both group A was lower than group B and C. Among the three groups, the area of β-PPA and γ-PPA was statistically significant ( H=36.535, 39.503; P<0.001, 0.001); the β-PPA area of group A and B was lower than that of group C; the γ-PPA area was group A <group B <group C. Peripapillary CVI of different regions in group A, group B and group C was statistically significant ( F=11.450, 5.037, 6.018, 4.489; P<0.05). The temporal CVI in group C was lower than that in group A and B; The inferior CVI of group C was lower than that of group A, and the superior and nasal CVI of group B and C were lower than that of group A. In multivariate analysis, SE ( β=0.374, P<0.001), temporal CVI ( β=-0.299, P<0.001) were correlated with the area of β-PPA (adjusted R2=296, P<0.001); AL ( β=0.452, P<0.001), temporal CVI ( β=-0.220, P<0.001) were correlated with the area of γ-PPA (adjusted R2=0.309, P<0.001). Conclusions:The incidence and area of γ-PPA are increased in the higher degree of myopia group. The area of γ-PPA is positively correlated with the axial length, and both the area of β-PPA and γ-PPA are negatively correlated with temporal CVI.

Comparison and correlation of choroidal parameters in children and adolescents with different refractive status / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To compare the choroidal parameters in children and adolescents with different refractive status, and to investigate the associations between ocular biometrics and choroidal parameters.METHODS:A cross sectional study. A total of 121 healthy children and adolescents(121 right eyes)aged 3-18 years treated in the Second People's Hospital of Hefei were collected. The data were divided into three groups according to spherical equivalent refraction(SER): emmetropia(-0.50&#x003C;SER≤+1.75D), low myopia(-3.00&#x003C;SER≤-0.50D)and moderate-to-high myopia(SER≤-3.00D). Ocular biometrics were measured by using the IOL Master. Data of the choroidal structures extracted from a 6mm sub-macular region centered on the fovea, including choroidal thickness(CT), the total choroidal area(TCA), luminal area(LA), stromal area(SA)and choroidal vascularity index(CVI)were determined by image binarization of the enhanced depth imaging-optical coherence tomography(EDI-OCT). Comparing all biology parameters among the three groups, associations among demographic factors, ocular parameters, and choroidal structures were evaluated by using multiple linear regression analysis.RESULTS:TCA, LA, SA and CT were all different among the three groups before age correction(all P&#x003C;0.001), and CVI was not different(P &#x003E;0.05). TCA, LA, SA, CT and CVI were found to be statistically different among the three groups after age correction(all P&#x003C;0.001), and there were differences in pairwise comparisons of TCA, LA, SA and CT among the three groups(all P&#x003C;0.001), which were the highest in emmetropic eyes and lowest in moderate-to-high myopic eyes, However, the CVI in pairwise comparisons among the three groups showed that only the moderate-to-high myopia group was significantly lower than the emmetropic group(P=0.014). Multiple regression analysis showed that the LA was significantly associated with SER(P=0.020), whereas CT were significantly associated with the axial length(AL)(P=0.028).CONCLUSIONS: The choroidal LA and CVI tend to decrease in children and adolescents with higher myopia, indicating that the decrease of sub-foveal choroidal blood flow may be related to the progression of myopia.

Changes of choroidal structure in children with hyperopic amblyopia observed by EDI-OCT technique / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To compare the differences in choroidal structure between hyperopic amblyopia and normal children of the same age by the enhanced depth imaging optical coherence tomography(EDI-OCT)technique.METHODS: There were 35 cases in 50 eyes of children with hyperopic amblyopia visiting our hospital in January 2021 to December 2021 selected in the amblyopic group, and 30 cases in 51 eyes of healthy children who matched general data in the same period were selected in the control group. EDI-OCT examination was performed to measure the choroidal thickness(CT). After image processing, the total choroidal area(TCA), luminal area(LA), stromal area(SA)and choroidal vascularity index(CVI)were obtained.RESULTS: TCA(except inferior quadrant), SA(except inferior quadrant of the outer ring), LA and CT(except inferior and temporal quadrant )in the amblyopic group of each area were significantly larger than that in the control group(P&#x003C;0.05), and there was no significant difference in CVI between the two groups except the temporal quadrant of the outer ring(P&#x003E;0.05). There was no significant difference in CT for all degrees of hyperopic amblyopia, with the exception of the nasal quadrant(P&#x003E;0.05).CONCLUSION: Hyperopic amblyopia is accompanied with abnormal choroidal structure. As the degree of hyperopia increases, TCA, LA and SA exhibit increasing trends. The changes in choroidal structure are presumed to be related to hyperopic amblyopia.

Choroidal hyper-reflective foci and vascularity in retinal dystrophy

Purpose: To investigate choroidal hyper-reflective foci (HRF) in subjects with retinal dystrophy [Stargardt's disease (SGD) and retinitis pigmentosa (RP)] and their association with demographics, visual acuity, choroidal thickness (CT), and choroidal vascularity index (CVI). Methods: Single center retrospective study of subjects with previously diagnosed SGD or RP. Swept-source optical coherence tomography images were analyzed for the presence of choroidal HRFs and CVI using previously validated automated algorithm. A Spearman's rank correlation coefficient was used to evaluate the correlation between the number of HRF and various baseline parameters including age, visual acuity, intraocular pressure, and other optical coherence tomography (OCT) parameters (CT, choroidal area, and CVI) were evaluated in these subjects. Results: This study included 46 eyes (23 subjects) and 55 eyes (28 subjects) with previously diagnosed RP and SGD, respectively. In the RP group, the mean number of HRFs was 247.9 � 57.1 and mean CVI was 0.56 � 0.04. In SGD group, mean HRF was 192.5 � 44.3 and mean CVI was 0.41 � 0.04. Mean HRF was significantly greater in the RP group (0.02), however, the mean CVI was not statistically different. In RP, mean HRF were correlated only with CVI (r = 0.49; P = 0.001), however, in SGD, it correlated with only choroidal area (r = 0.27; P = 0.04). Conclusion: Choroidal HRF were present in both RP and SGD subjects with more HRFs in those with RP. These HRFs were associated with alteration in choroidal vascularity, which further adds into the pathogenesis of these diseases.

A preliminary study of choroidal vascular index in patients with diabetic retinopathy / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To investigate the differences of the choroidal vascularity index between type 2 diabetes with diabetic retinopathy and non-diabetes patients.<p>METHODS: A retrospective cross-sectional study was performed at Beijing Friendship Hospital. Enhanced depth imaging spectral-domain optical coherence tomography(EDI-OCT)scans of 68 eyes of 68 type 2 diabetes who with diabetic retinopathy were compared with those of right eyes of 34 age- and gender-matched healthy controls. The choroidal images were binarized into luminal areas(LA)and stromal areas(SA). CVI was defined as the ratio of LA to total circumscribed subfoveal choroidal area. Mean choroidal thickness, mean retinal thickness and mean CVI between patients and controls were compared using <i>t</i>-test. <p>RESULTS: There were no significant differences in total circumscribed subfoveal choroidal area(0.53±0.14mm2 <i>vs</i> 0.49±0.15mm2), LA(0.35±0.09mm2 <i>vs</i> 0.32±0.10mm2), SA(0.17±0.05mm2 <i>vs</i> 0.17±0.06mm2), or subfoveal choroidal thickness(347.9±76.9μm <i>vs</i> 325.9±92.9μm)between patients with DR and controls(<i>P</i>>0.05). However, there was a significantly lower CVI in patients with diabetes as compared to controls(64.33%±3.25% <i>vs</i> 67.04%±2.46%, <i>P</i><0.001). The critical value was 63.59%.<p>CONCLUSION: CVI is a kind of biological indicators which can directly reflect the changes of choroidal internal structure, and it is more stable and reliable than SFCT. For type 2 diabetic patients who with diabetic retinopathy, CVI is lower than that of healthy people.

Diurnal variation in subfoveal and peripapillary choroidal vascularity index in healthy eyes

Purpose: To report the diurnal variation in choroidal vascularity index (CVI) in subfoveal (SF-CVI) and peripapillary area in healthy eyes. Methods: The study was a cross-sectional study including 12 healthy subjects. Swept-source optical coherence tomography scans were taken at 9 am, 11 am, 1 pm, 3 pm, and 5 pm. Subfoveal choroidal thickness (SFCT) and CVI were calculated using automated segmentation techniques and previously validated algorithms. Systemic parameters including systolic blood pressure (SBP), diastolic blood pressure, mean arterial pressure, and mean ocular perfusion pressure were calculated and correlated with SFCT and CVI. Results: A total of 12 eyes (right eye) of 12 patients (mean age: 26 ± 3.77 years) were analyzed. The mean (±standard deviation) amplitude of SFCT and SF-CVI variation was 35.91 ± 14.8 ?m (range, 15–69 ?m) and 0.05 ± 0.02 (range, 0.02–0.08). The mean CVI showed a significant diurnal variation in the temporal quadrant of the peripapillary region (P = 0.02). Conclusion: SFCT and SF-CVI showed a significant diurnal variation in amplitude (peak–trough analysis) and SF-CVI correlated well with SBP suggestive of a direct influence of blood pressure on choroidal vascularity. The mean peripapillary CVI in the temporal quadrant also showed a significant diurnal variation with no significant change in other quadrants.

Effect of Acetazolamide on Choroidal Morphology in Central Serous Chorioretinopathy

PURPOSE: We sought to elucidate the influence of acetazolamide on choroidal structure changes during the treatment of central serous chorioretinopathy (CSC).METHODS: This was a retrospective study of 45 eyes from 45 patients with acute CSC who were divided into an acetazolamide group (group 1, n = 20) and an observation group (group 2, n = 25). The main outcome measures were the changes in best-corrected visual acuity, subretinal fluid (SRF) height, subfoveal choroidal thickness (SFCT), and choroidal vascularity index (CVI) at one week, one month, two months, and three months, respectively.RESULTS: Although statistical significance was not reached, best-corrected visual acuity improved in both groups at month 3 (from 0.06 ± 0.07 to 0.01 ± 0.03 in group 1 and 0.17 ± 0.24 to 0.09 ± 0.18 in group 2; p = 0.083 and 0.183, respectively). Separately, SRF height and CVI showed a significant decrease at three months in both groups (all p < 0.05), while a significant SRF height decrease was also noted in group 1 at one month (p = 0.038). In group 1, a significant decrease in the SFCT and CVI started at one week and one month (p = 0.021 and 0.008), respectively. However, in group 2, a significant decrease in the SFCT and CVI started at one month and two months (p = 0.005 and 0.015), respectively.CONCLUSIONS: Acetazolamide has no effect on final functional or anatomical status at three months in eyes with CSC but does shorten the time for SRF absorption and accompanying choroidal structural changes.

Measurement and analysis of choroidal vascularity index and subfoveal choroidal thickness in central serous chorioretinopathy / 中华眼底病杂志

Objective To observe the choroidal vascularity index (CVI) and the subfoveal choroidal thickness (SFCT) of central serous chorioretinopathy (CSC),and to compare the stability and consistency of the two methods of measurement.Methods A retrospective study.Thirty-one patients with unilateral acute CSC who visited the Department of Ophthalmology of Beijing Friendship Hospital for the first time during the period from Nov 1st,2016 to Mar 18th,2018 were included in the study.Thirty-one healthy age-matched subjects were enrolled as controls.All CSC affected eyes and their fellow eyes and healthy eyes were scanned by single-line enhanced depth imaging of OCT through central fovea of macula to measure their SFCT.The image was binarized and then the CVI of a 1500 μm range below fovea was calculated,i.e.the ratio of vascular (or lumen) area to total choroidal area.CVI and SFCT were compared among CSC eyes,fellow eyes and healthy eyes by variance analysis.Intra-group correlation coefficient (ICC),Bland-Altman curve and coefficient of variation (CV) were used to analyze the repeatability,consistency and stability of CVI and SFCT;and Medcalc18.2.1 software was used to draw the Bland-Altman curve and observe the consistency of the two measurement methods.Results There were statistically significant differences in CVI and SFCT between CSC affected eyes and fellow eyes (t=3.470,2.844;P=0.001,0.006),CSC affected eyes and healthy eyes (t=6.977,6.277;P＜0.001,＜0.001),fellow eyes and healthy eyes (t=3.508,3.433;P=0.001,0.001).Relative consistency analysis of CVI and SFCT showed that the ICC of single measurement and average measurement of CVI were 0.967 and 0.983 respectively,and that of single measurement and average measurement of SFCT were 0.937 and 0.967 respectively.The consistency of CVI and of SFCT was very good.The ICC value of CVI was slightly higher than that of SFCT.The results of repeatability analysis of CVI and SFCT showed that the difference between the two CVI measurements was smaller,and the difference between the two SFCT measurements was larger.And CVI and SFCT stability analysis results showed that the CV of CVI and SFCT were 10.5％ and 25.3％ respectively.CVI has smaller CV than SFCT.Conclusions Compared with healthy eyes,CVI and SFCT are increased in CSC affected eyes and fellow eyes.And compared with SFCT,CVI has better consistency,repeatability and stability.

Qualitative comparison of choroidal vascularity measurement algorithms

Purpose: To compare the accuracy of manual and automated binarization technique for the analysis of choroidal vasculature. Methods: This retrospective study was performed on a total of 98 eyes of 60 healthy subjects. Fovea-centered swept source optical coherence tomography (SS-OCT) scans were obtained and choroidal area was binarized using manual and automated image binarization technique separately. Choroidal vessel visualization in the binarized scans were subjectively graded (grades 0–100) by comparing them with the original OCT scan images by two masked graders. The subjective variability and repeatability was compared between two binarization method groups. Intergrader and intragrader variability was estimated using paired t-test. The degree of agreement between the grades for each observer and between the observers was evaluated using Bland–Altman plot. Results: The mean accuracy grades of the automatically binarized images were significantly (P < 0.001) higher (93.38% ± 1.70%) than that of manually binarized images (78.06% ± 2.92%). There was a statistically significant variability and poor agreement between the mean interobserver grades in the manual binarization arm. Conclusion: Automated image binarization technique is faster and appears to be more accurate in comparison to the manual method.