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find Keyword "optical coherence tomography" 23 results
  • The changes in retinal and choroidal blood after scleral buckling surgery for rhegmatogenous retinal detachment

    Objective To observe the hemodynamic changes in the retina and choroid after scleral buckling surgery in eyes with rhegmatogenous retinal detachment (RRD). MethodsA prospective clinical observational study. A total of 25 eyes of 25 patients with RRD who underwent scleral buckling surgery in Tianjin Eye Hospital from February to April 2024 were included in the study. Among them, 10 were male and 15 were female. Age was 17-68 years old. All cases were monocular. The surgical eye and the contralateral healthy eye were divided into the affected eye group and the contralateral healthy eye group respectively. Best corrected visual acuity (BCVA), scanning source optical coherence tomography angiography (SS-OCTA), and axial length (AL) measurements were performed 3 months after surgery. SS-OCTA examination of macular area was performed by VG200 of Visual Microimaging (Henan) Technology Co., LTD. Scanning range 21 mm×26 mm. According to the partitioning method of the early treatment group of glycosuria retinopathy, the retina within 21 mm of the macular fovea was divided into concentric circles with the macular fovea as the center and diameters of 1-3, 3-6, 6-12, 12-21 mm, respectively. The built-in software of the device was used to record the central area (12 mm×12 mm in the fovea of the macula) and the peripheral area (12-21 mm range) retinal superficial capillary plexus (SCP), deep capillary plexus (DCP), radial peripapillary capillaries (RPC) blood density and choroidal vascular index (CVI), choroidal vascular volume (CVV), and 1-3, 3-6, 6-12, 12-21 mm above concentric circles (S), nasal side (N), temporal side (T), and lower side (I) SCP, DCP, and RPC blood flow density. Quantitative data between the two groups were compared by independent sample t test or Wilcoxon signed rank test. The correlation between retinal and choroid blood flow parameters and postoperative BCVA was analyzed by Spearman correlation analysis. ResultsCompared with the opposite healthy eye group, SCP blood density in the central area (Z=−4.372), DCP blood density in the central area (Z=−2.829), and CVI in the peripheral area (Z=−2.138) were decreased in the affected eye group, and the differences were statistically significant (P<0.05). SCP: in the affected eye group, the blood flow density in T3-6 mm, T6-12 mm, N6-12 mm and T12-21 mm regions decreased, while the blood flow density in I6-12 mm regions increased, with statistical significance (P<0.05). DCP: blood flow density in S6-12 mm, I6-12 mm, S12-21 mm and I12-21 mm regions decreased significantly, and the differences were statistically significant (P<0.05). RPC: blood flow density decreased significantly in T6-12 mm and I12-21 mm, and the differences were statistically significant (P<0.05). CVI: T6-12 mm, S12-21 mm, T12-21 mm, I12-21 mm significantly decreased, and T1-3 mm, S12-21 mm significantly increased, the differences were statistically significant (P<0.05). Correlation analysis showed that AL growth was positively correlated with CVV in central region (r=0.408, P=0.040) . The number of pad pressure was negatively correlated with the blood density of central DCP (r=−0.422, P=0.030). ConclusionsAfter scleral buckling operation, the blood flow density and choroidal blood flow parameters in RRD affected eyes are lower than those in contralateral healthy eyes in some areas. The increase of AL is positively correlated with CVV in the central region, and the wider the range of pad pressure, the worse the recovery of DCP blood density.

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  • Alterations of choroidal vasculature after submacular fluid absorption in central serous chorioretinopathy using ultra-widefield swept-source optical coherence tomography angiography

    ObjectiveTo analyze the associations between the choroidal vasculature and submacular fluid (SMF) in central serous chorioretinopathy (CSC). MethodsA retrospective study. A total of 29 CSC patients (31 eyes) with complete records who visited the Department of Ophthalmology in Peking University People's Hospital from August 1, 2021 to March 1, 2023 were included in this study. The patients were divided into complete absorption and incomplete absorption groups according to the status of SMF in the last visit. All the patients underwent ultra-widefield swept-source optical coherence tomography angiography (UWF SS-OCTA) with a scanning range of 24 mm × 20 mm. The UWF SS-OCTA images were automatically analyzed in 9 regions (superotemporal, superior, superonasal, temporal, central, nasal, inferotemporal, inferior, and inferonasal). Alterations of choroidal vasculature in the nine subfields after SMF absorption were described, including choroidal thickness (CT), flow density of choriocapillaris layer, vessel density of large choroidal vessel layer, three-dimensional choroidal vascularity index (CVI), the mean choroidal vessel volume (mCVV), and the mean choroidal stroma volume (mCSV). The relevant factors affecting the complete absorption of SMF were additionally evaluated. ResultsAt baseline, CT (Z=2.859, P=0.004), mCVV (t=2.514, P=0.018), and mCSV (Z=2.958, P=0.003) in the superotemporal region of the affected eyes in the incomplete absorption group were significantly higher than those in the complete absorption group. Compared with baseline, at the last visit, the proportion of asymmetric vortex veins in the complete absorption group was significantly decreased (χ2=6.000, P=0.014), CVI in the superotemporal, superonasal, temporal, central, nasal, inferotemporal, and inferonasal regions (t=-4.125, t=-3.247, Z=-3.213, t=-2.994, t=-3.417, t=-3.733, t=-3.795; P=0.001, 0.006, 0.001, 0.010, 0.005, 0.003, 0.002), the mCVV of 9 regions (t=-2.959, t=-2.537, t=-2.235, t=-3.260, t=-3.022, t=-2.796, t=-2.747, Z=-2.107, t=-2.935; P=0.011, 0.025, 0.044, 0.006, 0.010, 0.015, 0.017, 0.035, 0.012) were significantly decreased. Compared to the complete absorption group, the choroidal blood flow changes in the non-complete absorption group were more limited, and CT in the upper region increased significantly at the last follow-up (t=2.272, P=0.037). Multivariate logistic regression analysis revealed that baseline CT in the superotemporal region may be an independent risk factor affecting the complete absorption of SMF (odds ratio=0.981, 95% confidential interval 0.965-0.997, P=0.021). ConclusionsIn the process of SMF absorption in CSC, significant reductions of choroidal blood flow were found in the large choroidal vessel layer, and there may be a locally compensatory increase in CT. In addition, baseline CT in superotemporal region is an independent risk factor affecting SMF absorption.

    Release date:2023-05-18 10:05 Export PDF Favorites Scan
  • Pathological diagnostic value of respiratory optical coherence tomography in lung cancer

    Objective To explore the pathological diagnostic value of optical coherence tomography (OCT) in lung cancer. Methods This study selected patients who underwent general anesthesia and electronic bronchoscope biopsy at the Respiratory Endoscopy Center of Sichuan Provincial People’s Hospital from January 1, 2023, to December 1, 2023. White-light bronchoscopy (WLB), auto-fluorescence bronchoscopy (AFB), and OCT examinations were performed in all patients. Lesions were assessed for benign or malignant characteristics based on AFB and OCT before biopsy. The final pathological results were determined according to pathology report. Results A total of 124 patients were included in the study. The accuracy of OCT in differentiating the nature of lesions was 93.55%, significantly higher than AFB (accuracy 83.06%). The accuracy, sensitivity, and specificity of OCT were all higher than AFB. For squamous carcinoma, adenocarcinoma, and small cell lung cancer, the accuracy rates of OCT imaging characteristics were 91.94%, 94.35%, and 94.35%, respectively. Conclusion OCT can improve the accuracy of pre-bronchoscopic tissue pathology biopsy in determining the nature of lesions and provide rapid pathological typing basis, potentially further promoting the development of non-invasive histological biopsy.

    Release date:2024-05-16 01:48 Export PDF Favorites Scan
  • An optical coherent imaging system for measuring the strain of blood vessels

    We aimed to establish an optical coherence tomography (OCT) system to measure the strain of blood vessels. A general OCT system was constructed firstly and its reliability was confirmed by comparing the OCT imaging of the porcine coronary and the corresponding histological slices. The strain of the porcine coronary was induced by static flow pressure and correlation algorithm was used to calculate the strain field of blood vessels within OCT images. The results suggest that bright-dark stratification of blood vessels displayed in OCT images is consistent with the intima and media layers of histological image. Furthermore, the strain of media layer is greater than that of the intima layer under the same static pressure. The optical coherence imaging system could not only measure the histological structure of the blood vessels, but also qualify the vessel strain under flow pressure.

    Release date:2017-10-23 02:15 Export PDF Favorites Scan
  • Analysis of macular vascular density and retinal thickness of school-age children

    ObjectiveTo observe the correlation between retinal capillary density and retinal thickness in the macula and spherical equivalent (SE) in school-age children. MethodsA cross-sectional study. From May to December 2022, 182 school-age children who visited the ophthalmology department of the First Affiliated Hospital of Zhengzhou University were included . There were 95 males and 87 females. The age ranged from 6 to 12 years, and the spherical equivalent (SE) was +0.50 to -6.00 D. They were divided into three groups based on the SE of the right eyes: 54 eyes in emmetropia group (+0.50≤SE<-0.50 D), 71 eyes in low myopia group (-0.50≤SE<-3.00 D), and 57 eyes in moderate myopia group (-3.00≤SE≤-6.00 D). The macular area of 6 mm×6 mm was scanned using swept-source optical coherence tomography angiography and was divided into three concentric rings centered on the fovea, including the macular central fovea (0-1 mm diameter), inner ring (1-3 mm diameter) and outer ring (3-6 mm diameter). The retinal thickness and blood flow density of superficial vascular plexus (SVP) and deep vascular plexus (DVP) in different zones within 6 mm of the macular area were measured. The relationships between SE and SVP, DVP and retinal thickness in each ring region were investigated by univariate and multivariate linear regression analyses, smooth curve fitting, and threshold effects. ResultsThere were significant differences in the SVP (F=6.64, 26.06, 22.69) and DVP (F=7.97, 25.01, 5.09) of macular central fovea, inner ring and outer ring among the emmetropia, low myopia and moderate myopia groups (P<0.05). Univariate linear regression analysis showed that the SVP (β=-0.56, -1.17, -0.79) and DVP (β=-1.03, -0.93, -0.45) of the three regions were positively correlated with SE (P<0.05). After smooth curve fitting, threshold effect analysis and multivariate linear regression analysis, the SVP and DVP in the macular central fovea were linearly positively correlated with SE (β=-0.91, -1.40; P<0.05), and SVP and DVP in the inner ring and outer ring showed an inverted U-shaped curve relationship with SE with the inflection (<3.00 D). When the SE was less than <3.00 D, the SVP and DVP in the inner ring and outer ring were positively correlated with SE (P<0.05). When the SE was higher than -3.00 D, except for the DVP in the inner ring region, the other parameters were negatively correlated with SE (P<0.05). There were significant differences in retinal thickness of the inner ring and outer ring (F=5.47, 16.36; P<0.05), and no significant difference in the macular central fovea among the emmetropia, low and moderate myopia groups (F=2.16, P>0.05). By using univariate and multivariate linear regression analyses, the retinal thickness in the inner ring and outer ring were negatively correlated with SE (β =1.99, 3.05; P<0.05). However, no correlation was found between retinal thickness and SE in the macular central fovea (β=-1.65, P>0.05). ConclusionsIn school-age children with SE between +0.50 D and -6.00 D, the retinal capillaries density of the macular central fovea gradually increase, and increase first and then decrease in the inner ring and outer ring with increasing SE. The retinal thickness of inner ring and outer ring gradually decrease and not change significantly in the macular central fovea.

    Release date:2024-01-23 05:54 Export PDF Favorites Scan
  • Evaluation of the efficacy of a customized surgical approach for congenital optic disc pit with maculopathy

    Objective To observe the curative effect of a personalized surgical scheme based on scanning source optical coherence tomography (SS-OCT) image features in the treatment of congenital optic disc pit (ODP) with maculopathy (ODP-M). MethodsA prospective interventional cohort study. From September 2019 to May 2024, 15 patients with 15 eyes who were diagnosed with ODP-M by ophthalmology examination in Department of Ophthalmonogy of The First Affiliated Hospital of Zhengzhou University were included in the study. Best corrected visual acuity (BCVA) and SS-OCT were performed in all affected eyes. Standard E word visual acuity chart was used for BCVA examination, which was converted into logarithm of the minimum angle of resolution (logMAR) BCVA for record. The center retinal thickness (CRT) was measured by SS-OCT examination of macular area using VG200D of Henan SVision Imaging Technology Co., LTD. According to the morphological characteristics of ODP and the splitting, edema and detachment of macular region, combined with the degree of pulling of the boundary membrane between the posterior vitreous cortex and macular region, a personalized surgical method was designed. Class I: pars plana vitrectomy combined with macular boundary film stripping, ODP boundary film packing and vitreous cavity gas filling. Class Ⅱ: pars plana vitrectomy combined with non-retained macular boundary film stripping or ODP inner boundary film packing, vitreous cavity gas filling. Class Ⅰ and Class Ⅱ operations were performed in 10 and 5 eyes of 15 eyes, respectively. The postoperative follow-up time was >6 months. Follow-up time was performed with the same equipment before surgery. BCVA changes, CRT reduction rate and complications were observed. BCVA and CRT were compared before and after operation by paired sample t test. ResultsThere were 15 eyes in 15 cases, 4 eyes in 4 males and 11 eyes in 11 females. The age was (28.87±16.5) years. logMAR BCVA of the affected eye was 0.94±0.51. CRT was (697.80±301.80) μm. At the last follow-up, the logMAR BCVA was 0.53±0.49. CRT was (392.53±167.55) μm. Compared with before operation, BCVA and CRT were significantly improved, and the difference was statistically significant (t=3.23, 3.25; P=0.006, 0.006). After surgery, transient intraocular hypertension occurred in 2 eyes, and the intraocular pressure returned to normal level after 3 to 7 days without special treatment. Two eyes underwent an unexpected second operation. Among them, one eye underwent Class Ⅰ surgery, the tunnel at ODP was closed after surgery, and there was a small amount of subretinal fluid in the macular area. Class Ⅱ surgery was performed in 1 eye with retinal reattachment. ConclusionPersonalized surgical treatment of ODP-M based on SS-OCT image features can reduce CRT and improve visual acuity.

    Release date:2025-05-14 02:04 Export PDF Favorites Scan
  • Evaluation of Anterior Segment Parameters of Hyperopia of School-aged Children Using Anterior Segment Optical Coherence Tomography

    The aim of this study was to investigate the feasibility of anterior segment optical coherence tomography to assess the anterior segment morphology of hyperopia in school-aged children. 320 eyes of 160 school-aged children, 6-12 years of age, were examined with anterior segment optical coherence tomography and were divided into four groups according to the cycloplegic spherical equivalence of refractive error. The mentioned four groups were: emmetropia group, low hyperopia group, moderate hyperopia group and high hyperopia group. The measurements of central corneal thickness, anterior chamber depth, angle opening distance, trabecular iris space area and scleral angle were compared in pairs among objects in the four groups. The results showed that high hyperopia and moderate hyperopia had shallower anterior chamber depth and narrower anterior chamber angle compared to those in emmetropia group. The study also showed that anterior segment optical coherence tomography as a non-contact technology could become a new technology for accessing the anterior segment morphology of hyperopia in school-aged children.

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  • Study on the relationship between retinal and choroidal blood flow and the pathogenesis of idiopathic macular hole

    Objective To compare changes in retinal and choroidal blood flow in the macular area of eyes with idiopathic macular hole (IMH), fellow eyes, and normal eyes. Additionally, the correlation between these blood flow changes and the occurrence and development of IMH. Methods A cross-sectional study. From January 2023 to January 2024, 47 patients (47 eyes) diagnosed with IMH (IMH group) in Department of Ophthalmology of The Second Hospital of Hebei Medical University were included in the study. The contralateral eye of IMH eyes was assigned to the contralateral eye group. Healthy volunteers with matched gender and age were selected as the normal control group. Swept-source optical coherence tomography angiography was used to acquire the vessel density (VD) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in the areas within 0-1 mm and 1-6 mm around the fovea, including the superior, temporal, inferior, and nasal regions. Additionally, the choroidal blood flow area (CBFA) and three-dimensional choroidal vascular index (3D-CVI) were measured. The minimum linear diameter (MLD) and base diameter (BD) of the IMH were manually measured. Spearman correlation analysis was performed to evaluate the correlation between the size of the IMH and the various vascular parameters. ResultsCompared with the normal control group, the SCP-VD in the 3rd stage (t=1.298, P=0.009) and 4th stage (t=1.264, P<0.000) eyes in the IMH group was significantly decreased, with statistical significance; the DCP-VD (t=1.958, 2.150, 1.712, 1.667; P=0.027, <0.000, <0.000, <0.000) and 3D-CVI (t=0.027, 0.030, 0.024, 0.023; P=0.005, 0.003, <0.000, <0.000) in eyes of all stages were significantly decreased, with statistical significance; the CBFA in eyes of stages 2-4 was significantly decreased, with statistical significance (t=0.027, 0.022, 0.021; P=0.028, 0.002, 0.002). Compared with the contralateral eye group, the DCP-VD and 3D-CVI in the IMH group were significantly reduced, with statistical significance (Z=−3.289, −2.704; P=0.001, 0.007). Pairwise comparisons between eyes of different stages in the IMH group showed that SCP-VD was significantly different between stage 2 and stage 4 (t=1.776, P=0.008); DCP-VD was significantly different between stage 1 and stage 3, and stage 1 and stage 4 (t=1.685, 1.661; P=0.002, 0.000). Correlation analysis showed that SCP-VD was negatively correlated with MLD and BD (r=−0.508, −0.408; P=0.002, 0.014); DCP-VD was negatively correlated with BD (r=−0.410, P=0.013). Compared with the normal control group, the nasal CBFA in stage 3 and 4 IMH eyes (t=0.149, 0.145; P=0.005, 0.002), and the nasal 3D-CVI in stage 1 and 3 IMH eyes (t=0.030, 0.027; P=0.002, <0.000) were significantly decreased, with statistical significance. ConclusionsThe SCP-VD, DCP-VD, CBFA, and 3D-CVI in IMH eyes were significantly reduced. SCP-VD showed a negative correlation with MLD and BD, while DCP-VD was only negatively correlated with BD.

    Release date:2025-08-15 01:04 Export PDF Favorites Scan
  • Fundus imaging features of glucocorticoid-related central serous chorioretinopathy

    ObjectiveTo compare and observe the fundus imaging characteristics of eyes with glucocorticoid-related central serous chorioretinopathy (CSC). MethodsA retrospective clinical study. A total of 149 CSC patients with 166 eyes diagnosed at Department of Ophthalmology of The First Affiliated Hospital of Zhengzhou University from March 2021 to October 2024 were included in the study. The duration of the disease from the appearance of symptoms to treatment was less than 3 months. All affected eyes underwent best-corrected visual acuity (BCVA), fundus color photography, swept-source optical coherence tomography (SS-OCT), and fundus fluorescein angiography (FFA) examinations. BCVA was tested using an international standard vision chart and converted into logarithm of the minimum angle of resolution (logMAR) visual acuity for statistical analysis. The SS-OCT instrument measured subfoveal choroidal thickness (SFCT), central macular thickness (CMT), choroidal vascular volume (CVV), and the width and height of flat irregular pigment epithelial detachment (FIPED). FIPED, subretinal fibrin, and choroidal layer strong reflective spots were identified from SS-OCTA B-scan images; multiple leakages (leak points >3) were identified from FFA images. Based on the presence or absence of a clear history of glucocorticoid administration before the onset, patients were divided into glucocorticoid-related and non-glucocorticoid-related groups, comprising 41 patients with 53 eyes and 108 patients with 113 eyes, respectively. Clinical and fundus imaging characteristics of the two groups were compared. The comparison of quantitative data between the two groups was performed using independent samples t test or non-parametric independent samples Wilcoxon test; the comparison of qualitative data was performed using χ2 test. ResultsCompared with the non-glucocorticoid-related group, the glucocorticoid-related group had a smaller male-to-female ratio and a higher bilateral incidence, and the differences were statistically significant (χ2=4.925, 17.849; P<0.05). The logMAR BCVA for the glucocorticoid-related and non-glucocorticoid-related groups were 0.45±0.33 and 0.21±0.21, respectively; SFCT were (644.43±131.91) and (507.26±121.79) μm; CMT were (389.51±233.45) and (362.59±140.85) μm; CVV were (4.44±1.07) and (3.67±0.82) mm3; FIPED incidence were 58.49% (31/58) and 20.35% (23/113), respectively; FIPED width and height were (1 122.01±533.98) and (742.90±388.79) μm, and (99.13±92.17) and (33.01±15.99) μm; subretinal fibrin were observed in 24 (45.28%, 24/53) and 15 (13.27%, 15/113) eyes; choroidal strong reflections were found in 38 (71.70%, 38/53) and 45 (39.82%, 45/113) eyes; multiple leak points were identified in 35 (66.03%, 35/53) and 40 (35.40%, 40/113) eyes, respectively. Compared with the non-glucocorticoid-related group, the glucocorticoid-related group had worse BCVA (Z=−4.984), thicker SFCT (t=6.586), larger CVV (t=5.160), higher incidence of FIPED (χ2=23.908), and greater width and height of FIPED (t=2.895, Z=−3.703). The glucocorticoid-related group also had a significantly increased incidence of subretinal fibrin, choroidal strong reflections, and multiple leak points, with all differences being statistically significant (χ2=20.565, 14.663, 13.675; P<0.05); however, the comparison of CMT showed no statistically significant difference (Z=−0.651, P>0.05). ConclusionCompared with non-glucocorticoid-related CSC, glucocorticoid-related CSC patients have poorer vision, are more likely to affect both eyes, show no gender bias; choroidal vascular dilation is more significant, and damage to the outer retina and retinal pigment epithelium is more severe.

    Release date:2025-05-14 02:04 Export PDF Favorites Scan
  • Numerical Simulation of Heat Transfer in the Human Anterior Chamber at Different Corneal Temperatures

    A three-dimensional (3D) model of human anterior chamber is reconstructed to explore the effect of different corneal temperatures on the heat transfer in the chamber. Based on the optical coherence tomography imaging of the volunteers with normal anterior chamber, a 3D anterior chamber model was reconstructed by the method of UG parametric design. Numerical simulation of heat transfer and aqueous humor flow in the whole anterior chamber were analyzed by the finite volume methods at different corneal temperatures. The results showed that different corneal temperatures had obvious influence on the temperature distribution and the aqueous flow in the anterior chamber. The temperature distribution is linear and axial symmetrical around the pupillary axis. As the temperature difference increases, the symmetry becomes poorer. Aqueous floated along the warm side and sank along the cool side which forms a vortexing flow. Its velocity increased with the addition of temperature difference. Heat fluxes of cornea, lens andiris were mainly affected by the aqueous velocity. The higher the velocity, the bigger more absolute value of the above-mentioned heat fluxes became. It is practicable to perform the numerical simulation of anterior chamber by the optical coherence tomography imaging. The results are useful for studying the important effect of corneal temperature on the heat transfer and aqueous humor dynamics in the anterior chamber.

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