23G玻璃体视网膜手术后视网膜血管直径与神经纤维层厚度及视盘的变化

目的：调查接受睫状体平坦部玻璃体切割术及术中辅助治疗患者的视网膜血管直径,视网膜神经纤维层厚度和视盘改变。
　　方法：共40例(40眼)接受单侧睫状体平坦部玻璃体切割术及术中辅助治疗患者纳入研究,分别于术前、术后3 lo及6 lo行视网膜照相检测视网膜中央动脉和静脉的直径,应用修正Parr-Hubbard公式计算视网膜中央动脉当量和视网膜中央静脉当量。运用Stratus OCT检测视神经纤维层厚度。立体视盘摄影检测视盘的垂直杯盘比。
　　结果：术前患者的双眼视网膜血管直径与神经纤维层厚度及视盘检查无统计学差异。垂直杯盘比在3 lo和6 lo较术前明显增加(P<0.01, P<0.01),且手术眼与对侧眼显著不同(P<0.01, P<0.01)。术后6lo术眼视网膜中央动脉当量与视网膜中央静脉当量的改变明显大于对侧眼(P<0.01, P<0.01)。视神经纤维层厚度无显著变化。
　　结论：玻璃体切割术及术中辅助治疗在术后6 lo会引起视盘的垂直杯盘比及视网膜血管直径的改变,而视网膜神经纤维层厚度变化不明显。     

Pupil Dilation May Affect Retinal Vessel Caliber Measures

Purpose: To assess the effect of pupil dilation on measures of retinal vessel caliber.

Design: Observational study with self-comparisons

Methods: Retinal photographs were taken for both eyes of 25 subjects before and after pupil dilation. Three photographic graders, masked to pupil dilation status, measured the same set of images using a computer-assisted, semi-automatic method. We compared means (standard deviations) of retinal arteriolar caliber equivalent (CRAE) and retinal venular caliber equivalent (CRVE) of the same eyes between pre- and post-dilation images. We assessed concordance correlation coefficients (CC), Bland Altman limits-of-agreements, and used linear mixed models to assess CRAE and CRVE measures associated with pupil dilation (influencing image quality), graders (observers) and right-left eye variation.

Results: We found high CCs for CRAE (0.82-0.94) and CRVE (0.87-0.94) between pre- and post-dilation images of the same eyes across the graders. Bland Altman plots showed that mean differences ranged from 0.55-3.42μm for CRAE and 1.56-2.29μm for CRVE. After adjusting for right-left eye random variation, a significant fixed effect of dilation was evident in mean CRAE in two of the three graders. There was no significant fixed effect of dilation in mean CRVE across all graders. In models including data of both eyes’ measures from pre- and post-dilation images by three graders, the fixed effect for dilation status contributed significantly to CRAE and CRVE variances whereas random effects for graders and dilation status contributed minimally.

Conclusions: Contrary to our hypothesis, we found a systematic effect of pupil dilation on retinal vessel caliber measures.     

Retinal microvascular signs and incidence of abdominal aortic aneurysm: The Atherosclerosis Risk in Communities Study

Purpose: To test the hypothesis that retinal microvascular abnormalities known to predict other cardiovascular diseases are associated prospectively with risk of abdominal aortic aneurysm. The rationale is that aortic aneurysm involves small vessel pathology that parallels, to some degree, retinal vasculopathy.

Methods: In 1993–1995, the Atherosclerosis Risk in Communities (ARIC) Study, a prospective population-based cohort, took retinal photographs of a randomly selected eye of 10,911 ARIC participants (initial mean age 60 years). Staff centrally graded the photographs using central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) indices. We followed participants for incidence of abdominal aortic aneurysm (n = 378 events), measured via medical record linkage from 1993–1995 through 2011.

Results: Wider venular diameters were associated with increased incidence of abdominal aortic aneurysm, with the hazard ratio (95% CI) being 1.61 (1.20, 2.16) for the highest versus lowest quartile of CRVE. However, adjustment for other abdominal aortic aneurysm risk factors, particularly smoking, eliminated the association of CRVE with abdominal aortic aneurysm. CRAE and frank retinopathy showed no association with abdominal aortic aneurysm incidence.

Conclusion: This prospective study found that retinal vascular diameters and retinopathy are not associated with incidence of abdominal aortic aneurysm.     

Effect of capsular tension ring implantation on predicted refractive error after cataract surgery in patients with pseudoexfoliation syndrome

AIM: To investigate the effect of capsular tension ring(CTR) implantation on predicted refractive error after cataract surgery in patients with pseudoexfoliation(PEX) syndrome.METHODS: This double-blind randomized clinical trial was conducted on 60 patients with PEX syndrome referring to Imam Khomeini Hospital affiliated to Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran, for undergoing cataract surgery. The study population was divided into two groups, namely CTR group(n=30) and non-CTR group(control group;n=30). The refractive error and anterior chamber depth(ACD) were measured 1 wk, 1 mo, and 3 mo after phacoemulsification(PE) surgery.RESULTS: The results indicated no statistically significant difference between the two groups in terms of predicted refractive error(obtained by subtracting preoperative predicted refractive error from actual postoperative refractive error) 1 wk(P=0.47), 1 mo(P=0.30), and 3 mo(P=0.06) after the PE surgery. Regarding the CTR group, the changes of ACD was statistically significant 1 and 3 mo after the PE surgery, compared to those obtained 1 wk post-surgery(P=0.005).CONCLUSION: The CTR implantation in PEX cataractous patients without zonulysis has no statistically significant effect on the predicted refraction and ACD changes after PE. The predicted refraction error has a hyperopic shift in both groups. The results reveal the unnecessary of calculating modified IOL in CTR implantation.     

Relationships between age,blood pressure,and retinal vessel diameters in an older population

PURPOSE: To describe the cross-sectional relationships between age, blood pressure (BP), and quantitative measures of retinal vessel diameters in an older Australian population. METHODS: Retinal photographs from right eyes of participants (n = 3654, aged 49+ years) in the Blue Mountains Eye study taken during baseline examinations (1992-1994) were digitized. The width of all retinal vessels located 0.5 to 1.0 disc diameters from the disc margin was measured by a computer-assisted method. Summarized estimates for central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) represent average retinal vessel diameters. The arteriole-to-venule ratio (AVR) was calculated. Associations between age and BP and CRAE, CRVE, and AVR were assessed with generalized linear models. RESULTS: Retinal vessel diameters decreased with increasing age in both men and women. CRAE and CRVE decreased by 4.8 microm and 4.1 microm, respectively, per decade increase in age, after adjusting for sex and mean arterial blood pressure. Mean AVR declined by 0.01 for each increasing decade of age, until 79 years. After adjustment for age, sex, smoking, and body mass index, CRAE, CRVE and AVR were all significantly and inversely associated with BP. For every 10-mm Hg increase in mean arterial blood pressure, AVR decreased by 0.012 and CRAE and CRVE decreased by 3.5 microm and 0.96 microm, respectively. CONCLUSIONS: Retinal arteriolar and venular diameters narrow with increasing age, and these parameters are inversely related to BP, independent of age, gender, and smoking. The findings are consistent with those from the Atherosclerosis Risk in Communities Study suggesting that decreased retinal vessel diameters may reflect microvascular damage from elevated blood pressure.     

Comparison of Two Non-mydriatic Fundus Cameras to Obtain Retinal Arterio-venous Ratio

Purpose: To analyze device-dependent variability of two non-mydriatic fundus cameras to obtain arterio-venous ratio (AVR), central retinal arteriolar equivalent (CRAE), and central retinal venular equivalent (CRVE) in static vessel analysis (SVA).

Methods: We examined 53 participants (29 men, 24 women; median age 46 years) of the Study of Health in Pomerania (SHIP). We took 45° optic-disc-centered fundus images of the right eye with two different non-mydriatic fundus cameras. The first photograph was obtained from the TRC-NW 200, the second from the OCT 2000 (both Topcon Corporation, Tokyo, Japan). One experienced grader graded image quality from 1 “ideal quality” to 5 “not analyzable” and determined AVR, CRAE, and CRVE with the software Vesselmap3 (Imedos, Jena, Germany).

Results: Average image quality was 1.8 for the TRC-NW 200 and 1.6 for the OCT 2000. AVR could not be determined in 5 images of the TRC-NW 200 due to low image quality, while six images of the OCT 2000 were not analyzable. The difference between AVR taken from two different non-mydriatic cameras was 0.01?±?0.03 in Bland-Altman plots. The difference between CRAE was 0.17?±?10.15 and between CRVE was ?2.32?±?11.76.

Conclusions: The two different non-mydriatic cameras showed good agreement with respect to image quality. When using the same reading software, AVR, CRAE, and CRVE agreed well. Thus, funduscopy and SVA seem to be robust against inter-device variability. As a result, device dependency can remain unconsidered in follow-up examinations with different technical equipment. However, variability might impact more with devices from different manufacturers.     

视网膜血管直径和分叉角度与患者缺血性脑卒中的相关性

目的 探讨视网膜血管直径和分叉角度与患者缺血性脑卒中的相关性.方法 选取2019年1月至2020年6月在新乡医学院第一附属医院确诊为缺血性脑卒中的住院患者208例(413眼)为卒中组,以同期同年龄段未患有脑卒中者64例(128眼)为对照组.通过问卷调查和实验室检查获得患者的一般情况、吸烟和饮酒史以及血压、血脂情况;以视...     

Comparison of retinal vessel measurements in digital vs film images

PURPOSE: To compare central retinal artery equivalents (CRAE) and central retinal vein equivalents (CRVE) from vessels measured from images captured with a digital camera and digitized images taken with a film camera. DESIGN: Comparison of techniques. METHODS: SETTING: Clinic. Patients: A total of 75 eyes of 48 adults. OBSERVATION PROCEDURES: Gradings of retinal vessel diameters from images produced by using two photographic techniques: directly from a 45 degrees digital camera and digitized by scanning from a 30 degrees film-based camera. MAIN OUTCOME MEASURE: Differences in CRAE and CRVE from two types of images. RESULTS: CRAE and CRVE were highly comparable between the two techniques with correlation coefficients of 0.88 and 0.87, respectively. CONCLUSION: Estimates of CRAE and CRVE from measurements taken from digitally captured and digitized film-based images were highly comparable. It is likely that inferences about factors associated with retinal vessel diameters will be unbiased by the method of imaging.     

视网膜分支静脉阻塞视网膜微血管改变的定量研究

【摘要】 目的 研究视网膜分支静脉阻塞（BRVO）患者视网膜微血管改变的特点。设计 病例对照研究。研究对象 河北省邯郸市眼科医院连续的BRVO患者58例,对照组为“邯郸眼病研究”中按匹配原则抽取的非BRVO者200例。方法 对被研究者的眼底彩色照片定性判读视网膜微血管局部改变;利用计算机辅助软件（IVAN software, Australia）定量测量视网膜微血管管径,比较两组间的差异。主要指标 视网膜微血管局部改变包括局部视网膜动脉缩窄（FAN）、视网膜动静脉交叉压迫征（AVN）和动脉反光增强（OPAC）。定量测量指标为视网膜中央动脉直径（CRAE）、视网膜中央静脉直径（CRVE）和视网膜动静脉比值（AVR）。结果 CRAE、CRVE、AVR在BRVO组和非BRVO组分别为（136.0±20.7） μm Vs. （152.0±19.3） μm（P=0.000）;（207.2±23.1） μm Vs. （235.3±29.7） μm（P=0.000）;（0.66±0.13） Vs. （0.65±0.06）（P=0.019）。经多因素校正后视网膜血管局部改变FAN、AVN和OPAC在两组间比较的相对危险度分别为5.65（95%CI=1.77~18.03）、3.42（95%CI=1.48~7.89）和3.44（95%CI=1.44~8.24）（P均<0.05）。结论 视网膜动、静脉直径在BRVO者比非BRVO者均变窄,视网膜血管的局部改变在BRVO者比非BRVO者显著,因此视网膜血管的定量、定性分析可作为BRVO的观察指标。（眼科,2012,21：239-243）     

Correlation and Reproducibility of Retinal Vascular Geometric Measurements for Stereoscopic Retinal Images of the Same Eyes

Purpose: To assess the correlation and reproducibility of retinal vascular geometric measurements obtained from two stereo-paired fundus images.

Methods: Thirty stereoscopic pairs of color optic disc-centered photographs from the Blue Mountains Eye Study were analyzed. Side-by-side grading was performed by a single grader, using semi-automated computer software to quantify the following retinal geometric parameters: (1) retinal arteriolar/venular caliber (CRAE/CRVE); (2) arteriole-to-venule ratio (AVR); (3) branching angle; and (4) tortuosity. We used Pearson correlation (r), intra-class correlation coefficient (ICC), and Bland-Altman plots to assess within-pair correlation and reproducibility for each parameter measured.

Results: Inter- and intra-grader r and ICC were high (all r > 0.90 and ICC > 0.90), except for branching angle (ICCs between 0.69–0.83). There was no significant difference between within-pair means of all retinal vascular geometric parameters, before and after excluding poor quality images. CRAE, CRVE, AVR, and arteriolar and venular tortuosity showed very high within-pair correlation and agreement (all r > 0.80 and all ICC > 0.90 respectively). Arteriolar and venular branching angles demonstrated moderate within-pair correlation (r = 0.65 and r = 0.62, respectively) and within-pair agreement (ICC = 0.76 and ICC = 0.77, respectively).

Conclusions: Use of computer-assisted software to measure retinal vascular geometric parameters from paired fundus images was highly repeatable and is robust to differences in photographic angles of paired stereo images. Such measurements can be applied to evaluate temporal changes in longitudinal studies.     

Determination of retinal blood vessel diameters and arteriovenous ratios in systemic hypertension: comparison of different calculation formulae

Background Generalized arteriolar narrowing is one of the retinal changes influenced by systemic hypertension. The ratio of retinal arteriolar to venular diameters is often used as a marker of generalized arteriolar narrowing. There are several ways to determine the retinal arteriovenous ratio (A/V ratio). However, no comparison of retinal vascular measurements and A/V ratios determined by different formulae has been presented.Methods Eighty-seven men participating in the Tampere Ambulatory Hypertension Study returned for a 10-year follow-up examination in which fundus photographs were taken of both eyes. The diameters of retinal arterioles and venules were measured 1 and 2 disc diameters from the optic disc edge. The A/V ratio was determined using mean arteriole and venule width, the sum of widths of arterioles and venules, the sum of squares of widths of arterioles and venules, the central retinal artery equivalent (CRAE) and the central retinal venous equivalent (CRVE). The repeatability of measurements and A/V ratios was determined. Comparison was made between A/V ratios determined by different calculation formulas.Results In general, determination of A/V ratios yielded lower deviation than that of diameters of arterioles and venules separately. Calculation of A/V ratios using different formulas gave different ratio levels. According to linear regression analysis, the A/V ratio calculated using the sum of squares of widths of arterioles and venules correlated best with CRAE/CRVE (R ² 0.92) and A/V ratios calculated using the mean arteriole and venule widths or the sum of widths of arterioles and venules resulted in clearly lower associations (R ² 0.38–0.40 and R² 0.41–0.48, respectively). Of all A/V ratios, CRAE/CRVE had the best repeatability. No statistically significant differences were found between measurements from right and left eyes.Conclusions The high repeatability of CRAE/CRVE and sum of squares of widths of arterioles/sum of squares of widths of venules, as well as the good association of the two formulae, favor the use of these in evaluation of retinal vascular changes in systemic diseases. Our results also showed that if only one eye can be examined, it seems to suffice if fundus vascular alterations associated with systemic hypertension are evaluated.     

Heritability of retinal vessel diameters and blood pressure: a twin study

PURPOSE: To assess the relative influence of genetic and environmental effects on retinal vessel diameters and blood pressure in healthy adults, as well as the possible genetic connection between these two characteristics. METHODS: In 55 monozygotic and 50 dizygotic same-sex healthy twin pairs, aged 20 to 46 years, interpolated diameter estimates for the central retinal artery (CRAE), the central retinal vein (CRVE), and the artery-to-vein diameter ratio (AVR) were assessed by analysis of digital gray-scale fundus photographs of right eyes. RESULTS: The heritability was 70% (95% CI: 54%-80%) for CRAE, 83% (95% CI: 73%-89%) for CRVE, and 61% (95% CI: 44%-73%) for mean arterial blood pressure (MABP). Retinal artery diameter decreased with increasing age and increasing arterial blood pressure. Mean vessel diameters in the population were 165.8 +/- 14.9 microm for CRAE, 246.2 +/- 17.7 microm for CRVE, and 0.67 +/- 0.05 microm for AVR. No significant influence on artery or vein diameters was found for gender, smoking, body mass index (BMI), total cholesterol, fasting blood glucose, or 2-hour oral glucose tolerance test values. CONCLUSIONS: In healthy young adults with normal blood pressure and blood glucose, variations in retinal blood vessel diameters and blood pressure were predominantly attributable to genetic effects. A genetic influence may have a role in individual susceptibility to hypertension and other vascular diseases. The results suggest that retinal vessel diameters and the possible associated variations in risk of vascular disease are primarily genetic characteristics.     

儿童视网膜血管管径测量一致性分析

目的分析不同观察者使用计算机辅助的视网膜图像分析技术测量儿童视网膜血管管径的临床可靠性和一致性。方法横断面研究。1名熟练研究者和3名新培训研究者背靠背应用IVAN定量测量软件对100例4~8岁儿童的眼底图像视网膜血管进行测量。测量4个象限靠近视盘的视网膜中央动脉直径当量和视网膜中央静脉直径当量。通过半自动软件计算动静脉管径比例。计算组内相关系数（ICC）评价观察者间的一致性;将数据从低到高平均三等分转换成有序多分类资料,绘制列联表,并计算Kappa系数,评价3名新培训研究者分别与熟练研究者之间一致性;绘制Bland-Altman图评价观察者间的一致性。结果熟练研究者与3名新培训的研究者测量结果一致性良好。视网膜中央动脉直径当量分别为121.14±17.03、120.40±17.68、120.45±17.61、120.79±19.05,各研究者间ICC为0.943（0.923～0.960）,Kappa值分别为0.702、0.745、0.744。视网膜中央静脉直径当量分别为181.66±29.33、181.55±29.31、181.23±30.12、181.53±31.46,各研究者间ICC为0.939（0.917～0.956）,Kappa值分别为0.822、0.860、0.860。动静脉比值分别为0.67±0.06、0.66±0.07、0.67±0.06、0.67±0.06,各研究者间ICC为0.685（0.625～0.715）,Kappa值分别为0.753、0.604、0.601。结论利用IVAN软件对儿童视网膜血管直径进行测量一致性高,是可行和可靠的,可以为眼科医生定量分析视网膜血管直径提供依据。     

Ethnic variability in retinal vessel caliber: a potential source of measurement error from ocular pigmentation?--the Sydney Childhood Eye Study

PURPOSE: To describe the effects of ethnicity and iris color on measurement of retinal vascular caliber. METHODS: The Sydney Childhood Eye Study (SCES) examined 1740 6-year-old children from 34 randomly selected Sydney schools during 2003 and 2004. Retinal arteriolar and venular calibers (central retinal arteriolar [CRAE] and central retinal venular [CRVE] equivalents) were measured from retinal photographs by a standardized computer-assisted METHOD: Associations of retinal vascular caliber with ethnicity and iris color were analyzed. RESULTS: Of the total participants, 1612 (92.6%) had gradable retinal photographs. CRAE and CRVE were normally distributed, with means (SD) of 163.2 (14.0) and 227.3 (18.3) microm, respectively. Both arteriolar and venular calibers were substantially wider in the East Asian than in the Caucasian children (CRAE, 171.5 mum vs. 160.5 mum; and CRVE, 240.5 microm vs. 222.4 microm; P < 0.0001 for both comparisons). Among the Caucasian children, darker iris color was associated with wider arteriolar and venular caliber: CRAE increased from 157.5 microm in blue eyes to 169.2 microm in dark brown eyes (P for trend < 0.0001), and CRVE increased from 218.4 microm in blue eyes to 230.0 microm in dark brown eyes (P for trend < 0.0001). Among the children with dark brown eyes, there was no significant difference in CRAE between the Caucasian and the East Asian children, although mean CRVE was still approximately 10 mum wider in the East Asian than in the Caucasian children. CONCLUSIONS: Retinal vessel caliber was wider in the children of East Asian ethnicity. This difference was explained principally by darker iris color. Retinal pigmentation, as approximated by iris color, could be an important source of error in the measurement of retinal vessel caliber. If confirmed, this may affect comparisons of retinal vessel caliber between subjects with different ethnic backgrounds.     

Retinal vascular calibre and response to light exposure and serial imaging

Purpose: To investigate whether retinal vessel calibre measurements on optical retinal photography are affected by light and dark exposure prior to photography and whether the vessel calibre changes during an imaging sequence of several images. Methods: Digital optical retinal photographs were obtained from 32 healthy adults in two separate image sequences of six images during 1 min; one sequence with 10 min of dark exposure and one with 10 min of light exposure prior to imaging. Retinal arteriolar and venular calibres were measured computer‐assisted and summarized as central retinal artery and vein equivalents (CRAE and CRVE). Outcome measures were difference in calibres after prior light versus prior dark exposure and difference in calibre during each of the two imaging sequences. Results: CRVE was wider with prior light exposure (2.7%, p = 0.0001), comparing the first image in each image sequence. Within each sequence, there was a venular dilatation from first to last image, both with prior light exposure (1.7%, p = 0.0003) and prior dark exposure (3.1%, p < 0.0001), with the change less pronounced with prior light exposure (p = 0.0164). CRAE showed no significant change in either outcome. Conclusions: Retinal venular calibre was wider with light exposure prior to imaging and increased slightly during the imaging sequences, less pronounced after prior light than dark exposure. Measurement error due to these effects will probably be reduced by avoiding dark prior to imaging, and a possible bias effect of endothelial dysfunction may possibly be reduced by measuring calibre on an image taken early in the image sequence.     

北京市40岁以上中老年人群视网膜血管直径的五年变化

目的  观察北京市40岁及以上中老年人视网膜血管直径的5年变化及其相关因素。设计 队列研究。 研究对象 “北京眼病研究”5年随访人群中随机选取506人。方法 采用定量测量软件（Singapore I Vessel Assessment,SIVA3.2）对506例受检者随机一眼的彩色眼底照片中的视网膜血管直径进行测量。测量分区：距视盘边缘0.5~1 PD之间的环形区域为B区,距视盘边缘0.5~2 PD之间环形区域为C区。比较受检者基线与5年随访时各指标的变化情况,并分析其变化的相关因素。主要指标 B区和C区的视网膜中央动脉当量（CRAE）、视网膜中央静脉当量（CRVE）、视网膜动静脉直径比（AVR）、视网膜动脉平均直径（MWa）、视网膜静脉平均直径（MWv）、视网膜动脉直径的标准偏差（STDWa）和视网膜静脉直径的标准偏差（STDWv）、视网膜动脉长度直径比（length–diameter ratio arteriole,LDRa）和视网膜静脉长度直径比（length–diameter ratio venule,LDRv）。结果 506例受检者中348例（68.9%）基线和5年随访时均获得了可评价的眼底照片。与基线时相比,5年后的B区CRAE、CRVE均无明显变化（P均＞0.05）;C区CRAE、CRVE均明显增大（P均=0.001）;5年后的B区和C区AVR均无明显变化（P均＞0.05）。5年后的视网膜B区和C区MWa、MWv均明显减小（P均=0.000）;B区STDWa、STDWv明显增大（P均＜0.05）;C区STDWa、STDWv无明显变化（P均＞0.05）。5年后的视网膜LDRa、LDRv均明显增加（P均=0.000）。多因素分析表明,MWa的变化与年龄相关（r=0.105,P=0.041）;CRVE（r=5.733,P=0.029）、MWv（r=3.210,P=0.020）的变化与吸烟相关;STDWv的变化与高血脂相关（r=-0.204,P=0.023）;LDRv的变化与冠心病相关（r=5.088,P=0.044）。结论 40岁以上中老年人5年后视网膜动静脉均逐渐变细,动静脉比值相对稳定。视网膜血管直径的变化与吸烟、高血脂、冠心病等全身因素相关。     

Retinal vessel diameter in normal and glaucomatous eyes: the Beijing eye study

Purpose: To assess retinal vessel diameter in adult Chinese with and without glaucoma. Methods: The population‐based, cross‐sectional study included 4439 of the 5324 subjects asked to participate (response rate 83.4%), all aged 40 years or older. This study was divided into a rural part (1973 subjects [44.4%]) and an urban part (2466 subjects [55.6%]). Colour optic disc and fundus photographs were morphometrically examined for 2418 subjects. The retinal vessel diameters were measured at the optic disc border and at a distance of 2 mm to the optic disc border. The main outcome measure was the retinal vessel diameter. Results: Diameters of the retinal arteries were significantly (P < 0.001) the widest in the temporal inferior region, followed by the temporal superior region (P < 0.001), the nasal superior region (P < 0.001) and finally the nasal inferior region. Except for the nasal inferior vein, the same held true for the retinal veins. The sequence of the main four vessel trunks with respect to their diameters was not associated with age, gender or hyperopia versus myopia. The artery diameters showed a tendency to decrease in older age, while the vein diameters decreased across all age groups. Eyes with glaucomatous optic nerve damage showed significantly (P < 0.001) thinner arteries while the retinal vein diameters were not different. Conclusions: Diameters of the retinal arterioles and veins are the widest in the temporal inferior arcade, followed by the temporal superior arcade, the nasal superior arcade and finally the nasal inferior arcade. Retinal artery diameters decrease with glaucoma, and retinal vein diameters decrease with age.     

Static vessel analysis in nonmydriatic and mydriatic images

BACKGROUND: Static vessel analysis is a method to determine the diameter of retinal vessels in images of the ocular fundus. The suitability of non-mydriatic and mydriatic images for that method and the influence of mydriasis on the results were examined. MATERIALS AND METHODS: In the prospective study, 30 eyes of 15 patients (10 women, mean age 51.6 +/- 13.2 years) were examined. At first, 3 images were taken of each eye with the retinal camera Topcon NW 200 (magnification 1). After pupil dilation with tropicamid eye drops, 3 more images were taken using the Topcon and 3 others using the system Visualis (IMEDOS, Jena/Germany, FF450plus, 535-561 nm, 30 degrees image, 1840 x 1360 pixel). The vessel diameters were measured with the software Vesselmap2 (IMEDOS). The investigator assigned vessels to arteries or veins and their diameters were calculated automatically by the software. There is the possibility to define the vessel edge manually in cases of a poor image quality. The calculation of the central retinal arterial and venous equivalent (CRAE, CRVE) as well as the arterio-venous ratio (AVR) were made according to the formula of Parr-Hubbard. Furthermore, the nasal retinal vessels > 60 microm were examined to estimate the influence of tropicamid on the vessel diameter. RESULTS: Because of insufficient illumination and poor contrast in 21 % of the non-mydriatic images not all vessels could be detected automatically. Additionally, fewer vessels could be detected in 7 % of the non-mydriatic images compared to the mydriatic images. The average coefficient of variation of CRAE and AVR of each triplet of images was higher in non-mydriatic images (2.6 % and 3.2 %, respectively) than in mydriatic images of the Topcon (1.8 %; 2.3 %) and the FF 450 (1.7 %; 1.8 % ANOVA p < 0.05). No significant differences were found between the various examination methods for both the coefficient of variation of CRVE (1.9 %; 1.8 %; 1.7 %) and the average values of CRAE, CRVE and AVR. With regard to their diameters, the nasal retinal arteries and veins > 60 microm, were depicted sufficiently in all images, and only differed insignificantly between the three methods. CONCLUSION: The quality of non-mydriatic images is often lower than that of mydriatic images. This fact can account for the high variance of measured parameters in the non-mydriatic images. The depiction of all relevant vessel segments is a precondition for the image-based analysis. An influence of the mydriasis caused by tropicamid on the retinal vessel diameters > 60 microm was not found.     

Retinal Vascular Caliber and Kidney Function in Children and Adolescents with Type 1 Diabetes

Purpose: To evaluate the relationship between retinal vascular caliber and kidney function in a cohort of Australian children and adolescents with type 1 diabetes.

Methods: This was a cross-sectional study of 483 children and adolescents with type 1 diabetes, aged 7–18 years. An audit of medical files of participants who attended the Royal Children’s Hospital, Melbourne, between January 2009 and March 2014 was performed. Albumin to creatinine ratio (ACR) was acquired through spot urine samples and microalbuminuria was classified as ACR >3.5 mg/mmol in females and >2.5 mg/mmol in males. Retinal vascular caliber was measured using a standardized protocol and later summarized as central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE).

Results: CRAE was significantly narrower in participants with microalbuminuria compared to those with normo-albuminuria in crude analysis (mean ± standard deviation 159.07 ± 9.90µm vs 164.49 ± 12.45 µm; p = 0.006). After adjustment for key confounders and known or potential mediators of microalbuminuria (age, sex, ethnicity, hemoglobin A1c, systolic blood pressure, total cholesterol, body mass index, duration of diabetes and CRVE) the association between narrower CRAE and microalbuminuria was attenuated and was no longer significant (95% confidence interval 0.94–1.02, p = 0.222). No significant associations between CRVE or arteriole-to-venule ratio and microalbuminuria were observed in univariate or multivariate models.

Conclusions: After adjustment for potential confounding variables, retinal vascular caliber was not significantly associated with microalbuminuria in this sample of children and adolescents with type 1 diabetes. Future prospective longitudinal research is warranted to further evaluate these findings.     

Retinal vascular changes following intravitreal ranibizumab injections for neovascular AMD over a 1-year period

Purpose

To assess retinal vascular calibre changes in eyes with neovascular age-related macular degeneration (AMD), treated with intravitreal anti-vascular endothelial growth factor agents, over a 1-year period and compare any such changes to untreated fellow eyes.

Methods

Treatment naïve patients with neovascular AMD received three consecutive intravitreal injections of ranibizumab, followed by a pro re nata dosing regimen up to 1 year, with the aim of maintaining a ‘fluid-free'' macula. Retinal arteriolar and venular calibre was measured from digital fundus photographs at baseline and at three monthly intervals to 1 year, and summarised as central retinal artery equivalent (CRAE) and central retinal venular equivalent (CRVE), respectively.

Results

A total of 53 injected eyes and 41 fellow, non-injected eyes were analysed. At baseline, there were no differences in retinal vascular calibre between injected and non-injected eyes (mean CRAE (SD) 144.93 (14.07) vs 145.74 (13.10) μm, P=0.80 and mean CRVE (SD) 216.23 (25.93) vs 219.91 (22.82) μm, P=0.53). Over a 12-month period, retinal venular calibre dilatation occurred in injected eyes (mean CRVE change +5.71 (14.71) μm, P=0.007), with no change in retinal arterioles, +0.69 (14.71) μm, P=0.68. In non-injected eyes, arteriolar narrowing occurred as a whole, mean CRAE change −4.20 (7.00) μm, P=0.001, over 12 months, with a trend for narrowing in venules, −2.16 (11.56) μm, P=0.28. In injected eyes, after controlling for covariates, the changes in CRVE over 12 months mirrored improvements in macular thickness, −0.06 (−0.005, −0.11) μm, P=0.04, and visual acuity, +9.66 (−0.30, +19.32) μm, P=0.06.

Conclusion

Intravitreal ranibizumab significantly dilated retinal venules after a 1-year period.