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Retinal blood vessels are the only circulatory system that can be observed under non-invasive conditions. By observing the morphological changes of retinal blood vessels, the changes of blood circulation can be indirectly reflected. The occurrence, development and evolution of different diseases can be discovered. With the development of new detection technologies, especially the wide application of fundus photography and optical coherence tomography, a more intuitive and non-invasive quantitative index is provided for retinal vascular measurement. It is important for the diagnosis, guiding treatment and follow-up of related vascular diseases. This article reviews the development of retinal vessel diameter measurement methods and related applications in clinical diagnosis and treatment.
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Diabetic retinopathy (DR) is the most common cause of preventable blindness in the working-age population.In addition to optimizing the hyperglycemia,hypertension,hyperlipidemia and other risk factors,regular fundus examination is essential for early diagnosis asymptomatic DR and timely treat the sight-threatening DR,so as to reduce blindness and severe visual impairment caused by DR.Clinical practice guidelines for the screening and management of DR have been implemented throughout the world,but there are reasonable differences between existing guidelines in the recommended timing of first retinal examination,screening intervals,methods for examination and criteria for referral to an ophthalmologist.It is of great clinical significance to have a detailed understanding of the current guidelines for DR screening and their clinical basis.
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Objective To compare the imaging characteristics and detection of various types of lesions in diabetic retinopathy (DR) with colorful laser scanning fundus imaging (MSLI) and traditional color fundus photography (CFP).Methods Prospective case series observational study.A total of 38 eyes of 38 patients with DR diagnosed by clinical examination were included in the study.Among them,21 were male and 17 were female;the mean age was 62.6± 11.2 years;the average duration of diabetes was 14.3±7.5 years.All the patients were performed CFP,MSLI,frequency domain optical coherence tomography (SD-OCT),fluorescein angiography (FFA) examination.Using the Helielberg Spectralis HRA+OCT MSLI inspection,one scan simultaneously obtained 488 nm blue reflection (BR),515 nm green light reflection (GR),820 nm infrared light reflection (IR),and multicolor image (MC).The detection of traditional CFP and MC on microaneurysm (MA),hard exudation (HEX),cotton plaque (CWS),intraretinal hemorrhage (IRH),intraretinal microvascular abnormality (IRMA),venous bead (VB),venous ring (VL),macular edema (DME),macular anterior membrane (MEM) and laser photocoagulation (LB) were comparatively observed.The results of FFA examination were used as the diagnostic criteria for lesions.SD-OCT was used to determine the location and depth of lesions and the diagnostic reference for DME and MEM.Results The numbers of eyes with MA (x2=10.460),DME (x2=4.006),MEM (x2=4.444) was significantly higher in MC than that of traditional CFP.But the number of eyes with IRH (Z2=0.103),CWS (x2=1.515),HEX (x2=0.227),IRMA (x2=0.051),VB (x2=0.001),VL (x2=0.149),VH (x2=0.693) and LB (x2=0.720) were not statistically significant between two methods (P＞0.05).The imaging quality of MSLI mode is obviously better than that of traditional CFP.Among them,GR imaging shows the best structural changes of superficial retina in MA,CWS,HEX,MEM,etc.IR imaging shows clear depth in deep retina such as LB.DME was green on MC and the weak low-reflection dark area was visible on the IR image,which were consistent with the DME range indicated by the SD-OCT examination.Conclusions Compared with the traditional CFP,the MSLI can clearly show the DR lesion.The number of checkouts is high on MA,DME and MEM by MC image.
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Obejctive To investigate the consistency and reproducibility ofmacular perfusion parameters in early diabetic retinopathy (DR) using optical coherence tomography angiography (OCTA).Methods A prospective cross-sectional observational study.Forty-six patients (46 eyes) diagnosed with mild nonproliferative DR were included in this study.There were 24 males and 22 females,with the mean age of 59.16± 10.32 years.Two macular scan sizes of 3 mm× 3 mm and 6 mm× 6 mm were performed by the same operator,and the same test was performed by another operator.The superficial retinal layer (SRL) and deep retinal layer (DRL) in the foveal avascular zone (FAZ) and vessel density (VD) were quantified.The consistency of the two scan sizes and the reproducibility of the same scan size were also evaluated.The consistency was determined by the intraclass correlation coefficient (ICC).If the intraclass correlation coefficient (ICC)＞0.80,consistency was good;if 0.4≤ICC＜0.8,consistency was general;if ICC＜0.40,consistency was poor.Results In the 3 mm × 3 mm and 6 mm × 6 mm scanning sizes,the mean results of the two examiners were calculated.The FAZ of SRL were 0.39±0.13 mm2 and 0.42±0.15 mm2,FAZ of DRL were 0.74±0.22 mm2 and 0.89±0.23 mm2.The VD of SRL were (32.23±2.86)％ and (31.91 ±3.01)％,VD of DRL were (43.73 ±4.64)％ and (45.12± 5.49)％.The consistency analysis showed that the ICC of SRL-FAZ and DRL-FAZ were 0.920 and 0.812,respectively;the ICC of VD were 0.833 and 0.830,respectively.The consistency was good.The reproducibility analysis of different examiners in the same scan size was better in the consistency of SRL FAZ and VD.Conclusion OCTA in two scanning sizes to measure FAZ and VD of early DR has good consistency and reproducibility.
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Objective To observe the center retinal thickness (CRT) and subfoveal choroidal thickness (SFCT) in eyes with central retinal artery occlusion (CRAO) before and after treatment.Methods A total of 34 patients (34 eyes) diagnosed with CRAO by fundus fluorescence angiography (FFA) were retrospectively analyzed.There were 18 males (18 eyes) and 16 females (16 eyes).The average age was (61.42± 14.09) years.The mean onset time was (2.64±3.73) days.The mean hospitalization time was (11.92 ±4.95) days.The mean axial length (AL) was (23.53 ± 2.04) mm.The best-corrected visual acuity (BCVA),slit-lamp biomicroscopy,indirect ophthalmoscopy,fundus color photography,fundus fluorescein angiography,spectral domain optical coherence tomography (OCT) and AL measurement were performed.BCVA was converted to the logarithm of the minimum angle of resolution (logMAR).According to FFA,visual loss and the results of OCT,patients were divided into 3 groups:incomplete CRAO (15 eyes),subtotal CRAO (8 eyes),total CRAO (11 eyes).SFCT and CRT in affected and the fellow eye were measured by OCT for enhanced deep imaging.Follow up lasted for 1 month after treatment,with an average follow-up of (34.71 ± 6.82) days.The changes of S FCT,CRT,and BCVA before and after treatment were observed.The correlation between BCVA after treatment and pretreatment CRT was also analyzed.Results After 1 month of follow-up,the logMAR BCVA in incomplete group,subtotal group and total group were significantly higher than before treatment (t=3.74,3.61,3.26;P=0.004,0.009,0.017).Before treatment,the average CRT of the contralateral eyes in the total,subtotal and incomplete group were (215.00± 19.85),(224.00±22.79),(214.00±8.21) μtm,and the mean SFCT were (264.54± 121.71),(266.50±58.17),(261.86±90.95) μm.The average CRT of the affected eyes were (353.18±60.26),(280.14± 11.08),(266.63±19.65) μtm,and the average SFCT were (233.72± 111.35),(237.75 ± 53.30),(259.86±98.14) mm.Compared with the fellow eyes,the average CRT in the 3 groups were thickened,and the difference were statistically significant (t=8.274,3.694,11.577;P＜0.001,0.008,＜0.001);the average SFCT in the total group was decreased,the difference was statistically significant (t=-2.138,P=0.048).The mean CRT among the 3 groups of eyes was statistically significant (F=1 2.02,P＜ 0.001).There was no significant difference in the average SFCT (F=0.178,P=0.838).After 1 month follow-up,the mean CRT in the total,subtotal and incomplete group were (231.18 ± 49.28),(219.16± 21.34),(217.86± 24.98) μm,and the average SFCT were (239.81 ± 109.57),(241.86±42.81),(260.57±91.67) μan.Compared with before treatment,the average CRT in the three groups of eyes were decreased,the difference were statistically significant (t=13.032,3.711,4.970;P＜0.001,0.008,0.003);the difference in mean SFCT were not statistically significant (t=-0.785,-0.202,-0.078;P=0.466,0.845,0.940).Correlation analysis showed that BCVA after treatment was positively correlated with pretreatment CRT (odds ratio=0.578,P=0.002).Conclusion CRAO resulted in CRT in the preliminary stage and became thinner after receiving treatments.There exists a positive correlation between visual outcome and CRT before receiving treatments.
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Objective To investigate the relationship between glomerular filtration rate (GFR) and diabetic retinopathy (DR) and macular thickness in patients with type 2 diabetes mellitus (T2DM).Methods A total of 161 T2DM inpatients were enrolled in this study.There were 95 males (95 eyes) and 66 females (66 eyes),with an average age of (62.2±11.0) years.The average duration of diabetes was (14.8±7.9) years.The patients were grouped according to the degree of DR.Among them,91 patients were no DR,24 patients were mild non-proliferative DR (NPDR),24 patients were moderate NPDR,13 patients were severe NPDR and 9 eyes were proliferative DR (PDR).Severe NPDR and PDR were combine into severe DR group for statistical analysis.All patients underwent direct ophthalmoscope,fundus colorized photography,spectral domain optical coherence tomography (SD-OCT),fasting blood-glucose,glycated hemoglobin and renal function examinations.GFR was evaluated by 99 mTcDTPA.DR degree was evaluated by direct ophthalmoscope and fundus colorized photography.Central subfield (CSF),central macular volume and mean retinal thickness (MRT) were measure by SD-OCT.The correlation between GFR and DR staging and macular retinal thickness were analyzed by Spearman correlation analysis and Pearson correlation analysis.Logistic regression analysis was used to analyze the correlation between GFR and presence of DR.Results GFR was gradually decreased in patients with no DR,mild NPDR,moderate NPDR and severe DR (F=12.32,P＜0.001).Pearson correlation analysis demonstrated that GFR was negatively correlated to CSF (r=-0.202,P=0.010);but no correlation with MRT (r=-0.087,P=0.272).Spearman correlation analysis demonstrated that GFR was negatively correlated to DR staging (r=-0.325,P ＜ 0.001).The difference of DR prevalence rate in normal,slight abnormal renal function and renal insufficiency patients was significant (x2=12.32,P=0.002).Logistic regression analysis demonstrated that lower levels of GFR was significantly associated with presence of DR (95％ confidence interval=1.71-4.32,odds ratio=2.72,P＜0.001).Conclusion In T2DM patients,GFR is negatively correlated to DR staging and CSF.Lower GFR is independent risk factors for DR.
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Objective To observe the visual acuity change in patients with different patterns of optical coherence tomography (OCT) of diabetic macular edema (DME) after intravitreal ranibizumab injection and/or laser photocoagulation.Methods A retrospective observational case series.Seventy patients (99 eyes) with DME were enrolled.Best-corrected visual acuity (BCVA) was evaluated using the international vision test chart,and then convert the result to the logarithm of the minimum angle of resolution (logMAR).According to the morphological characteristics of OCT,the DME was divided into 3 patterns,including diffuse macular edema (DRT),cystoid macular edema (CME) and serous neuroepithelial layer detachment.The average follow-up was (80.43 ± 74.89) days.The patients were divided into 3 groups according to the different treatments,including intravitreal ranibizumab injection group (group A,21 patients,25 eyes),intravitreal ranibizumab injection and laser photocoagulation group (group B,23 patients,26 eyes),laser photocoagulation group (group C,26 patients,48 eyes).The changes of absolute BCVA (ABCVA) and improved visual acuity were compared between different treatment groups and different OCT patterns.ABCVA =logMAR BCVA before treatment-logMAR BCVA after treatment.Improvement more than 0.3 of logMAR value was considered as improved visual acuity.Results There was no significant difference in ABCVA between different treatment groups (F=0.050,P＞0.05).The improved visual acuity in group A and B were great than group C (x2=5.645,6.301;P＜0.05).In group A,B and C,there was no significant difference in ABCVA and improved visual acuity between different OCT patterns (P＞0.05).Improved visual acuity of DRT and CME eyes were higher in group A&B (70.59％ and 50.00％) than in group C (26.47％ and 14.29％),the difference was statistically significant (x2=5.075,4.453;P＜0.05).Conclusions There is no obvious change of visual acuity in patients with different OCT patterns of DME after the same treatment by intravitreal ranibizumab injection and/or laser photocoagulation.The improved visual acuity is not consistent in same OCT patterns after different treatment.
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Objective To investigate the distribution patterns of diabetic macular edema (DME) based on optical coherence tomography (OCT),and explore its correlation with diabetic retinopathy (DR) stages and systemic factors.Methods A total of 135 patients (242 eyes) with type 2 diabetes were included in this retrospective study.There were 75 males (138 eyes) and 60 females (104 eyes),the ages were from 29 to 83 years,with an average age of (5 8.8± 11.1) years.The general information such as height,weight,smoking history and blood glucose [such as glycosylated hemoglobin (HbA1 c)],blood pressure,blood lipid,24 hours urine protein and other examinations were collected.The diagnosis of DR and DME were made,and the staging of DR and typing of DME were performed based on fundus color imaging and OCT.DR were divided into mild nonproliferative DR (NPDR),moderate NPDR,severe NPDR and proliferative DR (PDR).DME were categorizedinto 4 types including sponge-like retinal swelling (SME),cystoid macular edema (CME),serous retinal detachment (SRD) and posterior hyaloid traction (PHT).The correlation between DME types and DR staging were analyzed by x2 test and Fisher exact test.Multivariate logistic regression analysis was used to analyze the correlation between DME types and systemic factors.Results In 242 DR eyes the proportions of mild,moderate,severe NPDR and PDR were 30.99％,32.64％,23.14％ and 13.23％,respectively.There were 199 eyes (82.23％) with DME.There were statistically significant differences in the proportion of DME in different stages of DR (x2=21.077,P＜0.01).In the 199 eyes with DME,There were 165 eyes (68.18％) of SME,22 eyes (9.09％) of CME,7 eyes (2.89％) of SRD and 5 eyes (2.07％) of PHT.The distribution of DME patterns in different stages of DR was statistically significant (x2=156.273,P＜0.01).Logistic regression analysis showed that the duration of diabetes,HbA1c and macroalbummuria were independent risk factors for DME [odds ratio (OR)=1.090,1.510,4.123;P＜0.05],and were also independent for SME (OR=1.092,1.445,3.942;P＜0.05);HbA1c wasanindependentriskfactorforSRD(OR=2.337,P＜0.05).Canclusions There are differences in the distribution of different DME types in each stage of DR.The duration of diabetes,HbA 1c and macroalbuminuria were independent risk factors for DME and SME,and macroalbuminuria and HbA1c for CME and SRD.
