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Swept-source optical coherence tomography angiography(SS-OCTA)is a new vascular imaging technique that was recently proposed. It has the advantages of being non-invasive, quick, high-resolution, and automated vascular stratification imaging. It is extremely helpful in the early diagnosis of ophthalmology-related diseases, as well as in the evaluation of treatment effectiveness and the tracking of disease progression. Based on the foundation of OCTA, SS-OCTA utilizes a fast-tuning laser with a wavelength of 1 050 nm for deeper penetration and non-invasive depth-resolved imaging of the retinal and choroidal microvascular systems, deepening the understanding of the characteristics of a wide range of ophthalmic diseases(fundus lesions, glaucoma, neurodegenerative diseases, etc.). The structures of the anterior segment of the eye can also be studied using SS-OCTA, including changes in the depth and density of corneal neovascularization as well as changes in iris neovascularization before and after therapy. This approach provides a novel tool for ophthalmic clinical practice. The development of the clinical use of SS-OCTA technology in ophthalmology is reviewed in this article.
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Purpose: Anterior segment optical coherence tomography (AS?OCT) by a swept source can visualize the ciliary body. The study was performed for analyzing the feasibility of a new swept?source OCT (Anterion) device for measuring iris ciliary sulcus, ciliary body thickness, and iris thickness. Methods: It is a pilot study among 30 normal young participants and hospital employees with their consent. The ciliary body, iris thickness, and ciliary sulcus were measured and compared to the results in the literature. We obtained 28 good?quality results. The main outcome measures were iris thickness (near and away from the pupillary margin), ciliary body thickness, and iridociliary sulcus measurement. Results: The iris thickness 2.5 mm from the pupillary margin was 0.70 ± 0.10 mm in the right eye and 0.68 ± 0.11 in the left eye. Closer to the root, the iris thickness varied from 0.55 ± 0.16 mm (right eye) and 0.57 ± 0.12 (left eye). Ciliary body thickness: Right eye 0.59 ± 0.14mm (28 good images), left eye 0.58 ± 0.13mm; ciliary sulcus (inner angle): right eye 82.65 ± 26.6°, left eye 83.66 ± 30.1°. Conclusion: Anterion OCT is feasible in our setting for various measurements and can provide valuable inputs to ophthalmologists for the treatment of ocular diseases.
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AIM: To investigate the changes in retinal and choroidal blood flow after pars plana vitrectomy(PPV)for proliferative diabetic retinopathy(PDR).METHODS: A cross-sectional study was conducted on 35 patients(35 eyes)who were diagnosed as monocular PDR and received 23GPPV in ophthalmology department of the Second People's Hospital of Hefei between September 2020 and July 2022. All eyes underwent swept-source optical coherence tomography angiography(SS-OCTA)examination. Retinal and choroidal vascular parameters within 3mm×3mm of macular zone were measured by built-in analyzer, and its correlation with postoperative best corrected visual acuity(BCVA)was analyzed.RESULTS: The follow-up was 1～22(average 9.72±6.67)mo. At the last follow-up, flow area(FA)of intermediate capillary plexus(ICP)layer in paranasal foveal region was significantly reduced in PPV eyes(0.31±0.06mm2)compared with contralateral eyes(0.38±0.05mm2), and FA of deep capillary plexus(DCP)in temporal foveal region was significantly lower in PPV eyes(0.19±0.08mm2)than contralateral eyes(0.27±0.07mm2; all P<0.05). Choroidal vascularity index(CVI)were lower in PPV eyes than contralateral eyes in parafoveal subregions except temporal region(P<0.05). After PPV, BCVA had a certain correlation with the density and FA of middle and deep retinal vessels.CONCLUSIONS: Eyes with severe PDR may be prone to having a decrease in the DCP and parafoveal choroidal perfusion in the parafoveal regions after PPV than contralateral eyes.
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AIM: To evaluate the characteristics of choriocapillary blood flow in different patients with diabetic retinopathy(DR)based on the measurement of choriocapillaris(CC)perfusion density(PFD)using ultra-high-speed swept-source optical coherence tomography angiography(SS-OCTA)METHODS: The cross-sectional observational study was conducted on 139 cases(139 eyes)who admitted to the Second People's Hospital of Hefei, including 115 DR cases(115 eyes)and 24 control cases(24 eyes). The color retinal images were graded according to the Early Treatment Diabetic Retinopathy Study(ETDRS)scale, and the DR eyes were classified into non-DR group, nonproliferative diabetic retinopathy(NPDR)group, NPDR combined with diabetic macular edema(DME)group and proliferative diabetic retinopathy(PDR)group. The ultra-high-speed SS-OCTA was used to scan a 3mm×3mm region centered on the macular central fovea, the CC perfusion area was measured by the built-in software, and PFD was calculated. Multivariable linear regressions were used to evaluate the correlation between PFD of CC and DR degree.RESULTS: The degree of DR had a correlation with blood perfusion of CC after adjusting for various confounding factors. When compared to the control group, the PFD of CC in the central fovea of the NPDR group decreased by 9.358 units(95%CI -18.484～-0.232, P=0.045)and 9.284 units in the paracentral fovea(95%CI -18.487～-0.090, P=0.048); In the NPDR combined with DME group, the central fovea CC PFD decreased by 18.173 units(95%CI -28.583～-7.762, P=0.001), while the paracentral fovea decreased by 17.032 units(95%CI -27.521～-6.544, P=0.002); In the PDR group, the central fovea CC PFD decreased by 28.309 units(95%CI -39.978～-16.640, P<0.001), while the paracentral fovea decreased by 25.841 units(95%CI -37.597～-14.085, P<0.001).CONCLUSION: The macular perfusion can be objectively quantified by the measurement of CC PFD with ultra-high-speed SS-OCTA. The CC PFD in the macular region was significantly reduced in more advanced stages of DR. Furthermore, future research should focus on longitudinal studies in the causal relationship between CC perfusion and DR progression.
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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<0.05). VD in the area of 3-6 mm showed a tendency to increase compared with the control group(t=1.715, P>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<0.05). There was no significant difference in CT, CVV and CVI between the two groups(P>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.
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AIM:To evaluate the correlation between axial lengths and anterior segment parameters using swept-source optical coherence tomography(SS-OCT).METHODS:For the cross-sectional clinical study, a total of 109 adult volunteers with different degrees of myopia recruited from January 1, 2022, to March 31, 2022, at the ophthalmology clinic of the First Affiliated Hospital of Zhengzhou University were included. Participants were divided into 4 groups based on axial length(AL): group A(AL≤24.0mm), group B(24.0mm<AL≤25.0mm), group C(25.0mm<AL≤26.0mm)and group D(AL>26.0mm). Anterior segment examinations were performed using SS-OCT, including: central corneal thickness(CCT), lens thickness(LT), anterior chamber depth(ACD), anterior chamber width(ACW), angle opening distance(AOD500), angle recess area(ARA500), trabecular iris space area(TISA500), trabecular iris angle(TIA500), crystalline lens rise(CLR). The relationships between these data and AL, spherical equivalent(SE)were analyzed.RESULTS:There was no difference in the comparison of CCT among the four groups(P>0.05). There were differences in SE, LT, ACD, ACW, AOD500, ARA500, TISA500, TIA500 and CLR among the four groups(all P<0.01). SE and LT were negatively correlated with AL(r=-0.75, -0.41, all P<0.01); ACD, ACW and CLR were positively correlated with AL(r=0.58, 0.45, 0.54, all P<0.01); AOD500, ARA500, TISA500 and TIA500(temporal and nasal side)were positively correlated with AL(all P<0.01). ACD and CLR were negatively correlated with SE(r=-0.21,-0.25, all P<0.01), and LT was positively correlated with SE(r=0.21, P<0.05).CONCLUSION:As AL increases, CCT remains unchanged while the ACD and ACW increase. The position of the crystalline lens moves backward and LT decreases.
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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.
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Objective:To evaluate the feasibility of measurement and characteristics of intraocular lens (IOL) tilt using the swept-source optical coherence tomography (SS-OCT) biometer (IOLMaster 700) and to explore its potentially relevant parameters.Methods:A cross-sectional study was conducted.Two hundred and forty-two eyes (119 right eyes, 123 left eyes) of 185 patients after phacoemulsification and IOL implantation were included in Beijing Tongren Hospital from July to September 2018.The IOL position, angle κ, angle α, corneal curvature, anterior chamber depth (ACD), pupil diameter (PD), and axial length (AL) were obtained by IOLMaster 700, and the IOL tilt direction and magnitude were calculated.The within-subject standard deviation and intraclass correlation coefficient were used to evaluate the repeatability of three IOL tilt measurements.Binocular symmetry of IOL tilt and the correlation between IOL tilt and different influencing factors were evaluated by Pearson linear correlation analysis or Spearman rank correlation analysis.Influencing factors for IOL tilt were assessed by multiple linear regression analysis.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Beijing Tongren Hospital, Capital Medical University (No.TRECKY2018-049). Patients were informed of the purpose and methods of this study and signed the written informed consent.Results:The repeatability of IOL tilt measurements was excellent with a within-subject standard deviation of 5.16° for IOL tilt direction and 0.13° for IOL tilt magnitude.IOL tilt was mirror symmetric in both eyes.The IOL tilt direction in right eyes ranged from -89.60° to 87.53° with a mean of (18.85±29.65)°, and the tilt magnitude ranged from 1.32° to 7.05° with a mean of (4.16±1.26)°.The IOL tilt direction in left eyes ranged from -84.30° to 89.44° with a mean of (21.17±32.38)°, and the tilt magnitude ranged from 0.58° to 7.40° with a mean of (3.80±1.31)°.There were moderate and weak positive correlations of IOL tilt direction and tilt magnitude between both eyes ( r=0.473, P<0.001; r=0.335, P=0.011). IOL tilt magnitude was weakly positively correlated with angle α and IOL diopter ( rs=0.272, P=0.003; r=0.285, P=0.002), and was weakly negatively correlated with ACD, PD and AL ( r=-0.303, P=0.001; r=-0.233, P=0.011; rs=-0.331, P<0.001). In backward stepwise regression analysis, the regression equation of IOL tilt magnitude, angle α, ACD, PD, AL and IOL diopter in multiple linear regression analysis was as follows: IOL tilt magnitude=10.503+ 1.456×angle α-0.532×ACD-0.196×AL ( R2=0.400; F=8.588, P<0.001). Conclusions:The SS-OCT biometer can be an effective method to assess IOL tilt.IOL tilt is mirror symmetric between the right eyes and left eyes.
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AIM: To explore Bland-Altman analysis of corneal curvature and astigmatism measured by new swept-source optical coherence tomography(SS-OCT)and Scheimpflug anterior segment analyzer in patients with age-related cataract.METHODS: A total of 177 patients(282 eyes)with age-related cataract admitted to the hospital between January and December 2021 were enrolled. The steep-axis curvature(Ks), flat-axis curvature(Kf), mean corneal curvature(Km), corneal astigmatism and astigmatism axis of anterior corneal surface, posterior surface and the whole cornea were measured by SS-OCT and Scheimpflug anterior segment analyzer respectively. All parameters were detected by paired sample t-test, intra-group repeatability test, Pearson correlation and Bland-Altman consistency analysis.RESULTS: There was no significant difference in Ks, Kf and Km of anterior corneal surface measured by SS-OCT and Scheimpflug anterior segment analyzer(P&#x003E;0.05). Ks, Kf and Km of posterior corneal surface and whole cornea measured by Scheimpflug anterior segment analyzer were all greater than those measured by SS-OCT(P&#x003C;0.05). There was no significant difference in astigmatism and axial values of anterior corneal surface, posterior surface and whole cornea measured by SS-OCT and Scheimpflug anterior segment analyzer(P&#x003E;0.05). The intraclass correlation coefficient(ICC)of all parameters was greater than 0.88, indicating a good intra-group repeatability. Ks, Kf, Km, astigmatism and axis of anterior corneal surface, posterior surface and whole cornea measured by SS-OCT were positively correlated with those measured by Scheimpflug anterior segment analyzer(P&#x003C;0.05). Bland-Altman consistency analysis showed that Ks, Kf, Km, corneal astigmatism and axis of anterior corneal surface, posterior surface and whole cornea measured by SS-OCT were highly consistent with those measured by Scheimpflug anterior segment analyzer(P&#x003C;0.05).CONCLUSION: The corneal curvature and astigmatism parameters measured by new SS-OCT are highly consistent with those measured by Scheimpflug anterior segment analyzer, which can be applied in the diagnosis of corneal curvature and astigmatism in patients with age-related cataract.
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Purpose: To evaluate the role of swept?source optical coherence tomography (SS?OCT) in the management of acute Vogt–Koyanagi–Harada’s (VKH) disease. Methods: Retrospective analysis of SS?OCT images of acute VKH patients between January 2015 and February 2020 in a tertiary eye care hospital. Results: We studied 34 eyes of 17 patients with acute probable VKH disease. The mean age was 31.6 ± 10.4 years. Twelve patients were women. The mean follow?up was 17.1 ± 9.3 months. The mean visual acuity was 0.86 logMAR (Snellen equivalent: 6/45) at presentation and 0.18 logMAR (Snellen equivalent: 6/9) at the last follow?up. The mean subfoveal choroidal thickness (SFCT) was 784.97 microns at presentation, 431.40 microns at the first month of therapy, 453.94 microns at six months of therapy, and 405.83 microns at the last follow?up. Qualitative features noted on SS?OCT on presentation was subretinal fluid (SRF) in 29 (85%) eyes, subretinal hyperreflective dots in 34 (100%) eyes, subretinal septa in 33 (97%) eyes, RPE undulations in 21 (61.7%) eyes, posterior vitreous cells in 34 (100%) eyes, SRF around disc in 9 (26%) eyes, and disc swelling in 34 (100%) eyes. At the end of 1 year of follow?up, RPE undulations were absent in 30 eyes (88%) and disc swelling was notably absent in all 34 eyes (100%), though SRF around disc was noted in 4 eyes (11.7%) of 2 patients who had recurrences. Conclusion: SFCT, SRF around disc, RPE undulation, and disc swelling may be important indicators on SS?OCT to guide therapy and prognosticate recurrences in acute VKH.
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Purpose: To investigate the retinal and choroidal microcirculation changes in celiac disease (CD) patients via optical coherence tomography angiography (OCT?A). Methods: This cross?sectional study included 44 pediatric patients with newly diagnosed CD and 44 healthy pediatric subjects. The vascular densities (VD) of the superficial, deep, and choriocapillar plexuses (VDs, VDd, and VDcc, respectively) (%), the superficial and deep foveal avascular zones (FAZs and FAZd) (%), the central macular thickness (CMT) (?m), and the subfoveal choroidal thickness (SFCT) (?m) were measured with swept?source OCT?A in addition to a complete ophthalmological examination. Results: Mean ages of the CD patients and the healthy participants were 12.02 ± 2.9 and 13.6 ± 2.3 years, respectively. The central sectors of the VDs and VDd measurements were found to be significantly higher in the study group compared to the control group (p = 0.006; P = 0.001, respectively), and the temporal and nasal values of the VDcc measurements were significantly lower in the study group than in the control group (p ? 0.05 for both values). CMT and FAZ metrics did not differ between the groups (p ? 0.05). SFCT was significantly reduced (p = 0.001), and choroidal thinning was more considerable in female CD patients (p = 0.045). Conclusion: CD seems to affect macular and choroidal microcirculation. The reduced choriocapillaris plexus parameters and choroidal thickness may provide disease activity information.
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Purpose: To assess the axial length (AL) measurement failure rate using partial?coherence interferometry (PCI) and swept?source optical coherence tomography (SS?OCT) in dense cataracts. As a secondary outcome, the SS?OCT biometry was compared to immersion ultrasound. Methods: This is a prospective cross?sectional and comparative study. Seventy eyes from 70 patients with dense cataracts were enrolled in this study. Dense cataract was defined according to the Lens Opacities Classification System III (LOCS III) scores equal to or more than NO4, NC4, C4, and P3. The failure rate of AL measurement was evaluated using PCI and SS?OCT. Anterior chamber depth (ACD), lens thickness (LT), and AL measurements obtained by SS?OCT were compared with IUS. Results: AL measurement failure rate with PCI was 68.57% and 21.43% with SS?OCT (P = 0.007). AL measurement was achieved in 69.23% of NO4, 66.6% of P3, and 15.3% of mixed cataracts using PCI, while SS?OCT was achieved in 100% of NO4, NO5, P3, and P5 and 76.9% of mixed cataracts. Cortical cataracts alone did not influence AL measurement. Biometric data of ACD, LT, and AL were statistically different comparing US and SS?OCT with a good correlation of AL. Conclusion: SS?OCT significantly improves the rate of successful AL measurements when compared to PCI in dense cataracts. The LOCS III clinical cut?off for the use of SS?OCT ocular biometry may well be up to P4 and NO5
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Objective:To characterize the distribution characteristics of choroidal thickness in healthy normal subjects and to define the diagnostic cut-off value for pachychoroid.Methods:A cross-sectional study design was carried out.Four hundred and forty-six eyes of 230 healthy subjects from the pachychoroid disease spectrum (PCD) cohort in Beijing Tongren Hospital from April 2018 to June 2021, were enrolled for the choroidal thickness distribution analysis.Three hundred and fourteen eyes of 274 patients with PCD including 149 eyes of 113 patients with central serous chorioretinopathy, 95 eyes of 81 patients with polypoid choroidal vasculopathy, 70 eyes of 60 patients with neovascular age-related macular degeneration, along with 382 eyes of 199 normal subjects matched for refractive error, age and gender with PCD were selected for likelihood ratio analysis.Routine eye examinations including the best corrected visual acuity, intraocular pressure, slit-lamp microscopy, dilated fundus examination and color fundus photography were performed in all subjects.Swept-source optical coherence tomography (SS-OCT) of 9 mm×9 mm scanning mode was used to measure the subfoveal choroidal thickness (SFCT) automatically in nine macular regions according to the Early Treatment Diabetic Retinopathy Study classification system using TOPCON Advanced Boundary Segmentation (TABS) software.Pearson linear correlation analysis and Spearman rank correlation analysis were adopted to evaluate the correlations between SFCT and age, diopter.Multiple linear regression was employed to analyze the factors affecting SFCT.After age and refractive error adjustment, the likelihood ratio test was used to determine the diagnostic cut-off value for pachychoroid.This study adhered to the Declaration of Helsinki.The study protocol was approved by an Ethics Committee of Beijing Tongren Hospital (No.TRECKY2016-054). Written informed consent was obtained from each subject prior to entering the cohort.Results:A negative correlation was found between SFCT and age in normal eyes ( r=-0.34, P<0.001), in both normal male and female subjects ( r=-0.43, P<0.001; r=-0.38; P<0.001). A weak positive correlation was found between SFCT and diopter ( rs=0.19, P<0.001). It was found that age and diopter were strongly correlated with SFCT (both at P<0.001). The cut-off values for pachychoroid in 20-39 years group, 40-59 years group, 60-79 years group and ≥80 years group were 320-330 μm, 330-340 μm, 250-275 μm and 200-225 μm, respectively.The percentages of eyes with pachychoroid in 20-39 years group, 40-59 years group and ≥60 years group were 14.71%(10/68), 24.48%(47/192) and 28.89%(55/184), respectively, showing statistically significant differences among them ( χ2=6.170, P=0.046; LR=6.579, P=0.037). The proportion of pachychoroid in ≥60 years group was significantly higher than that of 20-39 years group, showing a statistically significant difference ( χ2=5.982, P=0.014; LR=6.479, P=0.011). Conclusions:The distribution characteristics of pachychoroid vary in normal subjects over age.Age and diopter are the independent influencing factors of SFCT.
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Objective:To investigate the repeatability and correlation in tilt and decentration measurement of crystalline lens and intraocular lens (IOL) under non-mydriatic and mydriatic conditions using swept-source ocular coherence tomography CASIA2.Methods:A diagnostic test study was conducted.A total of 109 cataract patients (157 eyes) who received phacoemulsification with IOL implantation surgery in the Affiliated Hospital of North Sichuan Medical College from March to July 2020 were enrolled.The decentration and tilt of crystalline lens and IOL under non-mydriatic and mydriatic conditions were measured for three times by a single examiner using CASIA2 before and one week after surgery.The 0.5% compound tropicamide eye drops were used to dilate.Repeatability was evaluated by within-standard deviation, test-retest repeatability (TRT), coefficient of variation (CoV) and intraclass correlation coefficient (ICC). The correlation in decentration and tilt of crystalline lens and IOL between before and after mydriasis was assessed by Pearson correlation coefficient.This study adhered to the Declaration of Helsinki, and the study protocol was approved by an Ethics Committee of the Affiliated Hospital of North Sichuan Medical College (No.2020ER030-1). Written informed consent was obtained from all subjects before any medical examination.Results:The decentration of crystalline lens under non-mydriatic and mydriatic conditions was (0.217±0.112)mm and (0.220±0.110)mm, respectively, and the tilt was (5.017±1.422)° and (5.310±1.645)°, respectively.The decentration of IOL under non-mydriatic and mydriatic conditions was (0.245±0.136)mm and (0.250±0.145)mm, respectively, and the tilt was (5.144±1.345)° and (5.437±1.646)°, respectively.No significant difference was found between non-mydriatic and mydriatic conditions (all at P>0.05). Under both non-mydriatic and mydriatic conditions, the crystalline lenses of both eyes decentered and tilted toward the inferotemporal direction, and the IOL of right eyes decentered toward the inferior and tilted toward the inferotemporal direction, and the IOL of left eyes decentered and tilted toward the inferotemporal direction.Except the crystalline lens decentration, the measurement repeatability of crystalline lens tilt, IOL decentration and tilt in cataract patients before and after mydriasis was good, with ICC range in 0.815-0.984, TRT<50% and CoV≤14.840%.The measurement repeatability of crystalline lens decentration was poor, and the measurement repeatability of decentration axis, tilt and tilt axis of crystalline lens, and the repeatability of decentration and tilt of IOL were good in both eyes, with ICC range in 0.757-0.998, TRT<50% and CoV≤17.763%.There were good correlations in decentration, decentration axis, tilt and tilt axis of crystalline lens and IOL between non-mydriatic and mydriatic conditions (all r≥0.679, all at P<0.01). Conclusions:The measurement repeatability of decentration axis, tilt and tilt axis of crystalline lens and IOL, as well as the decentration of IOL by CASIA2 before and after mydriasis is good.The correlations of the measured parameters before and after mydriasis are good.
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@#AIM:To provide a clinical reference for the design of personalized surgical parameters for cataract, swept source optic coherence tomography angiography(SS-OCTA)was applied to comparatively study the blood flow of the macular area before operation in patients with different intraocular pressure during cataract surgery.METHODS: Prospective randomized controlled study. A total of 61 patients(77 eyes)who underwent cataract surgery in Sichuan Provincial People's Hospital from January to April 2021 were collected and divided into group A(37 eyes)and group B(40 eyes)for the study using a random number table. Group A and group B received the height of 75 and 90cm perfusion bottles with intraoperative,corresponding to 55.5 and 66.6mmHg intraoperative mean intraocular pressure,respectively. All patients were examined with SS-OCTA in macula area before and 1,7 and 30d after surgery, except routine ophthalmologic examination, the macular retinal thickness, the perfusion area and vessel density of the radial perioptic capillary plexus(RPCP)layer, superficial vascular plexus(SVP)layer, intermediate vascular plexus(IVP)layer and deep vascular plexus(DVP)layer were observed.RESULTS: There were no significant differences in the best corrected visual acuity(BCVA), intraocular pressure, foveal avascular zone(FAZ), macular retinal thickness, perfusion area and vascular density between the two groups at each time point before and after surgery(all <i>P</i>>0.05),but there were differences in time(all <i>P</i><0.05). In both groups, BCVA improved significantly from preoperative values at all time points after surgery, intraocular pressure and FAZ decreased compared with preoperative values(all <i>P</i><0.05), and macular retinal thickness, perfusion area in all layers, and blood flow density were increased compared with preoperative values.CONCLUSION:The macular retinal thickness, blood flow density and perfusion area of all layers increased,and the FAZ area decreased after cataract surgery, which may help to promote the recovery of visual acuity after surgery. At different intraocular pressures of 55.5 and 66.6mmHg intraoperatively, there was no significant difference in the patients'postoperative fundus blood flow changes, therefore, intraocular pressure can be flexibly selected during the operation to provide patients with personalized surgical design.
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AIM: To investigate the correlation between postoperative lens decentration and tilt and visual quality in eyes implanted with aspherical intraocular lens(IOL)by using a new anterior segment swept-source optical coherence tomography(OCT)CASIA2.METHODS: An observational study. A total of 90 eyes of 62 participants who underwent age-related cataract surgery at 1mo were included. Using CASIA2 by an experienced examiner, IOL tilt and decentration were obtained three consecutive times after mydriasis and the vector mean values were calculated. Double-pass optical quality analysis system(OQAS)and wavefront aberration instrument KR-1W were used for the visual quality measurements, including the total high-order aberration(tHOA), spherical aberration(SA), Coma, objective scatter index(OSI), modulation transfer function cut off frequency(MTF cut off)and Strehl ratio(SR)at 4 and 6mm pupil diameter.RESULTS: IOL decentration was positively correlated with SA(r=0.347, P=0.001)and OSI(r=0.343, P=0.002)at 4mm pupil diameter, and it was negatively correlated with MTF cut off(r=-0.244, P=0.032). There was no significant correlation between IOL decentration and tHOA, Coma and SR. IOL tilt was negatively correlated with MTF cut off(r=0.-345, P=0.002)and SR(r=-0.256, P=0.023)at 4mm pupil diameter, but it was not correlated with tHOA, SA, Coma and OSI. There were no significant correlations between the IOL decentration and tilt and tHOA, SA, Coma, MTF cut off and SR at 6mm pupil diameter.CONCLUSION: After aspherical IOL implantation in age-related cataract patients, IOL decentration was weakly correlated with SA at 4mm pupil diameter, while decentration and tilt were not significantly correlated with other higher-order aberrations. The decentration and tilt were weakly correlated with OSI value and MTF cut off value of the visual quality parameters. The results suggest that clinicians should pay more attention to higher-order aberrations and visual quality during precise cataract surgery.
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@#AIM: To compare the detection rate of axial length(AL)in cataract eyes by Tomey OA-2000 and IOL Master 500, and to evaluate the repeatability of OA-2000 in measuring ocular biometrics parameters. <p>METHODS: A cross-sectional study of 270 cataract eyes was implemented in the ophthalmic outpatient department from July to September 2018. Ocular biometric measurements including AL, keratometry readings(K), anterior chamber depth(ACD), lens thickness(LT), central corneal thickness(CCT), pupil diameter(PD)and white to white(WTW)were performed using OA-2000 and IOL Master 500. The detection rates of AL were calculated and compared between the two devices. <p>RESULTS: AL detection rates of 86.3%(233/270)and 97.0%(262/270)were found by IOL Master 500 and OA-2000 respectively. The mean difference in the measured AL by the two devices was(0.007±0.129)mm, and the 95% limits of agreement(95%<i>LoA</i>)of AL was 0.01(-0.24 to 0.26)mm. OA-2000 demonstrated good repeatability in measuring AL, ACD, K(2.5mm and 3mm pupil diameter), LT and CCT, but not in measuring PD and WTW. <p>CONCLUSION: Both OA-2000 and IOL Master 500 showed good agreement in AL measurement in cataract patients. However, compared with IOL Master 500, OA-2000 has a higher detection rate of AL. OA-2000 not only demonstrates excellent repeatability in ocular biometric measurements including AL, ACD, K, LT and CCT, but also more advantageous for the AL measurement of cataract with heavy lens opacity and subcapsular opacity.
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@#In recent years, ocular biometers based on swept-source optical coherence tomography(SS-OCT)technology have emerged in ophthalmic practice. Compared with the earlier ocular biometers such as the partially coherent interference(PCI)based ones, the SS-OCT based devices have a higher signal-to-noise ratio, greater swept light wavelength, better tissue penetration, faster scanning speed, and better axial length(AL)detection rate for cataract patients. This review aims to summarize the advances of a widely used SS-OCT based device-IOL Master 700 in cataract.
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@#AIM: To observe the morphological characteristics of posterior precortical vitreous pocket(PPVP)using swept-source optical coherence tomography(SS-OCT). <p>METHODS:Prospective study. One hundred and thirty-eight eyes of 91 cases with PPVP observed by SS-OCT in Henan Eye Hospital from March 2019 to June 2019 were included in the study. The average width and height size of PPVP was compared among subjects with different genders, age and equivalent spherical.<p>RESULTS: In 138 eyes, 112 eyes(81.2%)were ship shaped, 19 eyes(13.8%)were oval, and 7 eyes(5.1%)were hook shaped. Ninety-nine eyes(71.7%)had PPVP which connected with Martegiani area. The average width of PPVP was 6248.82±1117.87μm, and the average height of PPVP was 562.12±476.94μm. There was no difference in the width and height of PPVP between different genders(<i>P</i>>0.05), and the PPVP' width was positively correlated with age(<i>r</i>=0.32, <i>P</i><0.01). The PPVP' height in low myopia group were lower than that in non-myopia and moderate myopia group eyes(<i>P</i>=0.01, 0.03). <p>CONCLUSION: PPVP is a boat-shaped fluid cavity in front of the macula, which communicates with the Cloquet canal. Its width is related to the age. The existence of PPVP may play a role in the development of PVD and its progress.
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@#AIM: To evaluate the repeatability of a swept-source optical coherence tomography(SS-OCT)based biometer-IOL Master 700 in ocular biometrics in cataract eyes, and to investigate its agreement with a partially coherent optical interference based biometer-IOL Master 500. This study was also designed to compare the detection rate of the axial length(AL)measured by the two biometers. <p>METHODS:A total of 225 eyes of 133 cataract patients were included in this cross-sectional study from July to September 2018. Ocular biometric parameters including AL, keratometry(K), anterior chamber depth(ACD), lens thickness(LT), central corneal thickness(CCT)and white to white(WTW)were measured for each participant by both IOL Master 700 and IOL Master 500. <p>RESULTS: The IOL Master 700 measured <i>S<sub>w</sub></i> of AL, K<sub>m</sub>, K<sub>1</sub>, K<sub>2</sub>, ACD, LT, CCT, WTW in cataract patients were 0.027mm, 0.112D, 0.148D, 0.162D, 0.015mm, 0.010mm, 2.355μm and 0.134mm, <i>CoV</i> was 0.115%-1.162%, <i>ICC</i>≥0.923, the maximum <i>ICC</i> of AL is 1.000, and all measurements had high repeatability. The AL measured by IOL Master 700 and IOL Master 500 were(23.805±2.162)mm and(23.782±2.162)mm respectively, the difference was statistically significant(<i>t</i>=33.645, <i>P</i><0.001). However, the 95% <i>LoA</i> was 0.003mm-0.043mm, and the AL measured by the two biometers was significantly correlated(<i>r</i>=1.000, <i>P</i><0.001)with good agreement. The AL detection rates were 93.8%(211/225)for IOL Master 700 and 87.6%(197/225)for IOL Master 500, the difference was statistically significant(χ<sup>2</sup>=5.147, <i>P</i>=0.023).<p>CONCLUSION: IOL Master 700 demonstrates excellent repeatability in ocular biometric measurements including AL, K<sub>m</sub>, K<sub>1</sub>, K<sub>2</sub>, ACD, LT, CCT and WTW for cataract patients, especially in AL measurement. IOL Master 700 is in good agreement with IOL Master 500 in measuring AL, however the IOL Master 700 has a higher detection rate for AL in patients with severe opacity and subcapsular opacity in their lens.