Agreement of optical coherence tomography thickness measurements between Heidelberg Eye Explorer and ImageJ software

ObjectiveTo investigate the agreement and correlation of manual central foveal thickness (CFT) measurements using the Heidelberg Eye Explorer and ImageJ software.MethodsOptical coherence tomography (OCT) images were identified. CFT was measured using the Heidelberg Eye Explorer caliper tool. Two independent graders measured the CFT of the same images using ImageJ software. A Pearson correlation coefficient, intraclass correlation coefficient, Bland–Altman plots, and coefficient of repeatability were used to assess the agreement and correlation between the Heidelberg Eye Explorer and ImageJ measurements.ResultsOne-hundred and twenty-two OCT images from 91 patients were analyzed. Mean CFT as measured using the Heidelberg caliper tool was 264.8 ± 113 µm. Using ImageJ software, graders 1 and 2 obtained mean CFT values of 267 ± 114.3 µm and 270 ± 114.8 µm, respectively. Pearson correlation revealed a strong correlation between the Heidelberg and Image J measurements (r = 0.999, p < 0.0001). Bland–Altman plots noted a less than 4 µm mean difference between Heidelberg and ImageJ CFT values (2.67 ± 3.46 and 3.72 ± 2.78 µm for graders 1 and 2, respectively).ConclusionThere was strong agreement between the Heidelberg Eye Explorer and ImageJ software for manual CFT measurements. ImageJ may be a reliable tool for thickness measurements when proprietary OCT software is unavailable.     

In vivo three-dimensional high-resolution imaging of rodent retina with spectral-domain optical coherence tomography

PURPOSE: To demonstrate the application of high-resolution spectral-domain optical coherence tomography (SD-OCT) for three-dimensional (3D) retinal imaging of small animals and quantitative retinal information extraction using 3D segmentation of the OCT images. METHODS: A high-resolution SD-OCT system was built for in vivo imaging of rodent retina. OCT fundus images similar to those acquired with a scanning laser ophthalmoscope (SLO) were constructed from the measured OCT data, which provided precise spatial registration of the OCT cross-sectional images on the fundus. A 3D segmentation algorithm was developed for calculation of the retinal thickness map. OCT images were compared by histologic examination. RESULTS: High-quality OCT images of the retinas of mice (B6/SJLF2 for normal retina, rhodopsin-deficient Rho(-/-) for photoreceptor degeneration, and LH(BETA)T(AG) for retinoblastoma) and rat (Wistar) were acquired. The OCT images compared well with histology. Not only was a 3D image of the tumor in a retinoblastoma mouse model successfully imaged in vivo but the tumor volume was extracted from the 3D image. Retinal thickness maps were calculated that enabled successful quantitative comparison of the retinal thickness distribution between the normal (202.3 +/- 9.3 microm) and the degenerative (102.7 +/- 12.6 microm) mouse retina. CONCLUSIONS: High-resolution spectral-domain OCT provides unprecedented high-quality 2D and 3D in vivo visualization of retinal structures of mouse and rat models of retinal diseases. With the capability of 3D quantitative information extraction and precise spatial registration, the OCT system made possible longitudinal study of ocular diseases that has been impossible to conduct.     

Comparability of retinal thickness measurements using different scanning protocols on spectral-domain optical coherence tomography

Retinal thickness measurements obtained using optical coherence tomography (OCT) play an essential role both in multi-center clinical trials and in normal clinical practice. Different scanning protocols are available on most OCT devices, and it is important to ascertain whether the retinal thickness measurements obtained from these are comparable. This study aimed to compare retinal thickness measurements between raster and radial scanning protocols using spectral-domain OCT (SD-OCT). In a prospective study, 32 healthy subjects were scanned sequentially using raster and radial protocols from a SD-OCT device. For both the raster and radial OCT scans, retinal thicknesses were measured manually subfoveally and at 12 other points at 0.5 mm intervals temporally and nasally on the horizontal OCT B-scan passing through the fovea. The retinal thickness measurements were compared using intraclass correlation (ICC) and Bland–Altman plots. Subfoveal retinal thickness was 227.0 µm when measured on the raster scan and 229.2 µm on the radial scan, with a mean difference of 2.2 µm (P = 0.141).The ICC for agreement was 0.889 (95 % confidence interval 0.818–0.933). Similar results were observed for retinal thickness measurements at all other points, with mean differences ranging from ?3.37 to 2.59 µm, and ICC values ranging from 0.837 to 0.972. The retinal thickness measurements obtained by the raster and radial scans of the same SD-OCT device are comparable, with differences of less than 4 µm. This is of relevance when measurements made using different OCT scan protocols are compared.     

Calculating the predicted retinal thickness from spectral domain and time domain optical coherence tomography – comparison of different methods

Purpose

To compare the accuracy of different methods of calculating predicted central retinal thickness values in order to allow comparison between results of spectral-domain optical coherence tomography (SD-OCT) and time-domain OCT (TD-OCT) devices.

Methods

In a prospective cohort study, 100 consecutive healthy individuals without ocular disease underwent sequential scanning with SD-OCT (Spectralis OCT) and TD-OCT (Stratus OCT). A group of 60 eyes was used to generate the conversion equations, which were tested on the remaining 140 eyes. Four equations were used: 1. Mean difference between SD-OCT and TD-OCT; 2. Multiplying a ratio by the original retinal thickness; 3. Linear regression analysis using retinal thickness; and 4. Regression analysis using retinal thickness and spherical equivalent. All four methods were used to calculate predicted SD-OCT values from TD-OCT measurements, and vice versa.

Results

For all four equations, the predicted SD-OCT central retinal thickness values were similar to the actual SD-OCT, with mean difference ranging from 0.78 to 1.01 μm, and intraclass correlation coefficients >0.88. Both regression equations and mean difference showed greater accuracy, with variation between calculated and actual retinal thickness values ≤5 μm in 60 % of eyes. In contrast, the ratio method was less accurate, with 15.8 % of eyes showing differences >15 μm. Similar results were found for predicted TD-OCT values.

Conclusions

Several methods can be used to convert central retinal thickness values from SD-OCT to the predicted TD-OCT value, or vice versa, with high degrees of accuracy and reliability. These methods may allow comparison of OCT values from SD-OCT and TD-OCT devices in clinical trials and standard patient care.     

Noninvasive imaging by optical coherence tomography to monitor retinal degeneration in the mouse.

PURPOSE: Optical coherence tomography (OCT) is a high-resolution imaging technique that measures the intensity of backscattered light from biological microstructures in living tissue. The objective was to evaluate OCT as a routine, noninvasive technique for quantitative measurements of retinal thickness and detachment in small animal models of retinal degenerative diseases. METHODS: An OCT scanning unit was designed and built to visualize retinal tissue from rodents at high resolution in vivo. Several normal and retinal degeneration (rd) mouse strains with different pigmentation, as well as a transgenic mouse strain that carries a wild-type beta-PDE gene in an rd/rd background, were analyzed at different ages. Retinal detachment was induced by subretinal injection of saline. Retinal function was evaluated by full-field ERG, and then each retina was cross-sectionally scanned by OCT. OCT image analysis and measurements of retinal thickness were performed. Animals were then killed and retinal histology was documented. RESULTS: OCT images of the mouse retina revealed structural landmarks allowing assignment of retinal structures. There was no difference in the OCT pattern between pigmented and nonpigmented mice. Changes in the retinal thickness measured by OCT correlated very well with the loss in function measured by ERG and histology in rd/rd and rd/rd/tg(+) transgenic mice at a variety of ages. In addition, retinal detachment caused by surgery was easily visualized and observed by OCT imaging. CONCLUSIONS: OCT imaging is applicable to the mouse retina. There is excellent agreement between the retinal thickness measured by OCT, ERG amplitude, and retinal histology, thus validating OCT imaging as a sensitive and noninvasive tool for monitoring the structural progression of retinal diseases in rodent models. OCT also appears useful for visualizing retinal detachments in the mouse.     

急性Vogt-小柳-原田综合征黄斑相干光断层扫描观察

目的观察急性Vogt-小柳-原田综合征(VKH综合征)的相干光断层扫描(OCT)图像特征以及与临床的关联。探讨新型频域OCT在急性VKH综合征结构特征和定量分析中的临床价值。方法回顾分析临床确诊的急性VKH综合征21例(42眼)的OCT检查资料。所有患者接受最佳矫正视力(BCVA)、直接或间接检眼镜、裂隙灯显微镜+前置镜检查和荧光素眼底血管造影(FFA)检查。5线扫描(5 line Raster)模式下通过中心凹的水平+垂直两条扫描线的分析,对黄斑区视网膜各层结构变化的细微结构进行观察,用软件自带cliaper功能模块手工测量黄斑中心小凹厚度(FT)、神经上皮脱离高度(SRD)、神经上皮厚度(SRT)。在立方体(Cube)扫描模式下,采用软件自带的功能模块对黄斑中心厚度(CFT)、黄斑中心凹体积(V)、平均厚度(AT)进行测量。回顾分析时,重点分析黄斑区视网膜各层结构变化的细微结构,以及OCT图像特征与视力的相互关系。结果所有急性VKH综合征患者均可见后极部浆液性视网膜脱离。FT(r=0.2,P=0.00),SRD(r=0.83,P=0.00),CFT(r=0.81,P=0.000),AT(r=0.59,P=0.0001)和V(r=0.58,P=0.0001)值与初始视力呈负相关。视网膜色素上皮(RPE)上存在膜结构的35眼,平均视力为0.86±0.40logMAR,差于无膜结构的7眼(P=0.0074)。结论频域OCT可对急性VKH综合征特征性的黄斑改变进行定性及定量的观察,具有一定的诊断与鉴别诊断价值。VKH综合征的OCT图像特征性表现为:治疗前的渗出性视网膜脱离,"膜样"、"隔状"结构和RPE皱折,以及激素治疗后的"颗粒样"结构。存在"膜样"结构视力更差,FT和神经上皮脱离高度可能可反映脉络膜炎症的程度和疾病的严重程度。     

Scanning laser ‘en face’ retinal imaging of epiretinal membranes

Purpose

Comparison of scanning laser ophthalmoscopy (SLO) based ‘en face’ imaging techniques of patients with epiretinal membranes (ERM) and evaluation of the accuracy of preoperative diagnostic imaging.

Methods

A consecutive, prospective series of 53 study eyes of 46 patients with clinically diagnosed and in optical coherence tomography (OCT) confirmed symptomatic ERMs were included in this study. Spectral domain (SD-) OCT volume scans (20° × 20° with 49 horizontal sections, ART 15) including SLO en face and fundus autofluorescence (FAF) images of the macula were obtained with HRA2 (Heidelberg Retina Angiograph-Optical Coherence Tomography, Heidelberg Engineering, Heidelberg, Germany). In addition, wide-field SLO color and FAF images (Optomap 200Tx, Optos PLC, Dunfermline, UK) were performed also covering the macular area. En face images of both devices were graded for each included study eye based on SD-OCT cross sectional scans.

Results

Grading of SD-OCT (HRA2) based SLO en face green–blue enhanced multi-color, green reflectance, blue reflectance and standard multi-color visualization revealed a better detectability of ERM than SD-OCT-based en face infrared or FAF images or wide-field SLO (Optomap) based pseudo-color, red laser separation, green laser separation, or FAF images. Both FAF visualizations, HRA2 and Optomap based, achieved low mean scores. SD-OCT based en face thickness map visualization revealed good visualization but poor demarcation of epiretinal membranes.

Conclusions

In summary, en face regular or enhanced multicolor SLO images acquired with HRA2 allow a better visualization of epiretinal membranes for preoperative evaluation compared to SD-OCT based en face thickness map or pseudo-color images acquired with Optomap while infrared or FAF images are least suitable to depict epiretinal membranes.     

Visualization of Sarcoid Choroidal Granuloma by Enhanced Depth Imaging Optical Coherence Tomography

Abstract

Purpose: To report, in vivo, on the quasi-histologic characteristics of a sarcoid choroidal granuloma as visualized by Enhanced Depth Imaging Spectral Domain Optical Coherence Tomography (EDI SD-OCT).

Methods: A 49 year-old woman showing a choroidal granuloma secondary to sarcoidosis was imaged by EDI OCT.

Result: On EDI SD-OCT examination, sarcoid choroidal granuloma appears as a localized hyporeflectivechoroidalthickening. Two weeks after systemic corticosteroids, the thickness of the granuloma decreased from 568?μm to 356?μm. Five months later, it reached 274?μm, and after eleven months, it decreased to 150?μm.

Conclusion: EDI SD-OCT allows direct visualization of choroidal granuloma secondary to sarcoidosis and evaluation of lesion regression after treatment.     

Correlation with OCT and histology of photocoagulation lesions in patients and rabbits

Purpose:  To examine spectral domain optical coherence tomographic (OCT) and histological images from comparable retinal photocoagulation lesions in rabbits, and to correlate these images with comparable OCT images from patients. Methods:  508 rabbit lesions were examined by HE‐stained paraffin histology. 1019 rabbit lesions versus 236 patient lesions were examined by OCT, all at the time‐points 1 hr, 1 week and 4 weeks after photocoagulation. We analysed 100 μm lesions (in humans) and 133 μm lesions (in rabbits) of 200 ms exposures at powers titrated from the histological threshold up to intense damage. Lesions were matched according to morphological criteria. Results:  Dome‐shaped layer alterations, retinal infiltration by round, pigmented cells, outer nuclear layer interruption, and eventually full thickness retinal coagulation are detectable in histology and OCT. Horizontal damage extensions are found 1½ times larger in OCT. More intense irradiation was necessary to induce comparable layer affection in rabbit OCT as in histology. Restoration of the inner retinal layers is only shown in the OCT images. Comparable primary lesions caused more pronounced OCT changes in patients than in rabbits during healing. Conclusions:  Optical coherence tomographic images indicate different tissue changes than histologic images. After photocoagulation, they show wider horizontal damage diameters, but underestimate axial damage particularly during healing. Conclusions on retinal restoration should not be drawn from OCT findings alone. Retinal recovery after comparable initial lesions appears to be more complete in rabbit than in patient OCTs.     

Retinal Nerve Fiber Layer Thickness Reproducibility Using Seven Different OCT Instruments

Purpose. The clinical utility of new optical coherence tomography (OCT) instruments strongly depends on measurements reproducibility. The aim of this study was to assess retinal nerve fiber layer (RNFL) thickness reproducibility using six different spectral-domain OCTs (SD-OCTs) and one time-domain OCT. Methods. RNFL thickness (average and four quadrant) from six SD-OCTs (Spectral OCT/SLO OPKO/OTI, 3D-OCT 2000 Topcon, RS-3000 NIDEK, Cirrus HD-OCT Zeiss, RTVue-100 Optovue, and Spectralis Heidelberg) and one time-domain OCT (Stratus OCT Zeiss) was measured twice in 38 right eyes of 38 randomly chosen healthy volunteers by two masked operators. Inter- and intraoperator reproducibility was evaluated by the intraclass correlation coefficient (ICC), coefficient of variation (CV), and Bland-Altman test analysis. Instrument-to-instrument reproducibility was determined by ANOVA for repeated measures. We also tested how the devices disagree in terms of systemic bias and random error using a structural equation model. Results. Mean RNFL average thickness ranged from 90.08 μm to 106.51 μm. Cirrus and Heidelberg showed the thinnest RNFL values in all measurements, Topcon the highest. ICC, CV, and Bland-Altman plots showed variable inter- and intraoperator agreement depending on the instrument. Heidelberg demonstrated the best interoperator (ICC, 0.92; CV, 1.56%) and intraoperator (ICC, 0.94 and 0.95; CV, 1.28% and 1.26%, respectively, for operator A and operator B) agreement for average RNFL thickness. Conclusions. Heidelberg demonstrated the higher agreement in inter- and intraoperator reproducibility, Optovue the worst. In light of our error analysis results, we found that a scale bias among instruments could interfere with a thorough RNFL monitoring, suggesting that best monitoring is obtained with the same operator and the same device.     

Interchangeability of macular thickness measurements between different volumetric protocols of Spectralis optical coherence tomography in normal eyes

Backgrounds  

To evaluate in healthy eyes the interchangeability of retinal thickness measurements resulting from different protocols of Spectralis optical coherence tomography (OCT, Heidelberg Engineering, Germany).     

SD-OCT检测视网膜神经纤维层厚度的可重复性研究

目的 探讨频域光学相干断层成像术(SpectralDomain Opticalcoherence tomography,SD-OCT)检测正常人视网膜神经纤维层(RNFL)厚度的可重复性结果.方法 同一操作者应用SD-OCT的6mx6m3D视乳头200X200扫描模式(包括200次B扫描和200次A扫描)对36例(43只眼)正常人进行视乳头环形扫描,测量全周平均厚度、4个象限和12钟点位的RNFL厚度值,采用变异系数(coefficient of variation,CV)和类内相关系数(intraclasscorrelationcoemcient,ICC)来计算.结果 全周视网膜神经纤维层厚度的ICC和CV值范围分别为0.853～0.991,1.4%～5.8%.其中,上方象限的ICC值最高为0.991.鼻侧象限的ICC值最低为0.853,全周平均厚度的CV最低为1.4%,3钟点位的CV最高为5.8%.ICC值分别是上方>平均>颞侧>下方>鼻侧.与其相对应的12钟点位,11点、12点和1点的ICC值分别为0.974、0.988、0.964,2点、3点、4点的ICC值分别为0.940、0.853、0.907,5点、6点、7点的ICC值分别为0.933、0.959、0.980,8点、9点、10点的ICC值分别为0.965、0.924、0.966.结论 SD-OCT检测正常人视网膜神经纤维层厚度可重复性几乎一致,在检测青光眼的早期进展方面更有用.     

SD-OCT检测视网膜神经纤维层厚度的可重复性研究

目的 探讨频域光学相干断层成像术(SpectralDomain Opticalcoherence tomography,SD-OCT)检测正常人视网膜神经纤维层(RNFL)厚度的可重复性结果.方法 同一操作者应用SD-OCT的6mx6m3D视乳头200X200扫描模式(包括200次B扫描和200次A扫描)对36例(43只眼)正常人进行视乳头环形扫描,测量全周平均厚度、4个象限和12钟点位的RNFL厚度值,采用变异系数(coefficient of variation,CV)和类内相关系数(intraclasscorrelationcoemcient,ICC)来计算.结果 全周视网膜神经纤维层厚度的ICC和CV值范围分别为0.853～0.991,1.4%～5.8%.其中,上方象限的ICC值最高为0.991.鼻侧象限的ICC值最低为0.853,全周平均厚度的CV最低为1.4%,3钟点位的CV最高为5.8%.ICC值分别是上方>平均>颞侧>下方>鼻侧.与其相对应的12钟点位,11点、12点和1点的ICC值分别为0.974、0.988、0.964,2点、3点、4点的ICC值分别为0.940、0.853、0.907,5点、6点、7点的ICC值分别为0.933、0.959、0.980,8点、9点、10点的ICC值分别为0.965、0.924、0.966.结论 SD-OCT检测正常人视网膜神经纤维层厚度可重复性几乎一致,在检测青光眼的早期进展方面更有用.     

SD-OCT检测视网膜神经纤维层厚度的可重复性研究

目的 探讨频域光学相干断层成像术(SpectralDomain Opticalcoherence tomography,SD-OCT)检测正常人视网膜神经纤维层(RNFL)厚度的可重复性结果.方法 同一操作者应用SD-OCT的6mx6m3D视乳头200X200扫描模式(包括200次B扫描和200次A扫描)对36例(43只眼)正常人进行视乳头环形扫描,测量全周平均厚度、4个象限和12钟点位的RNFL厚度值,采用变异系数(coefficient of variation,CV)和类内相关系数(intraclasscorrelationcoemcient,ICC)来计算.结果 全周视网膜神经纤维层厚度的ICC和CV值范围分别为0.853～0.991,1.4%～5.8%.其中,上方象限的ICC值最高为0.991.鼻侧象限的ICC值最低为0.853,全周平均厚度的CV最低为1.4%,3钟点位的CV最高为5.8%.ICC值分别是上方>平均>颞侧>下方>鼻侧.与其相对应的12钟点位,11点、12点和1点的ICC值分别为0.974、0.988、0.964,2点、3点、4点的ICC值分别为0.940、0.853、0.907,5点、6点、7点的ICC值分别为0.933、0.959、0.980,8点、9点、10点的ICC值分别为0.965、0.924、0.966.结论 SD-OCT检测正常人视网膜神经纤维层厚度可重复性几乎一致,在检测青光眼的早期进展方面更有用.     

Evaluation of the Ganglion Cell Complex and Retinal Nerve Fiber Layer in Low,Moderate, and High Myopia: A Study by RTVue Spectral Domain Optical Coherence Tomography

Purpose: To assess the effect of low, moderate, and high myopia on the thickness of the retinal nerve fiber layer (RNFL) and Ganglion cell complex (GCC) measured by Spectral Domain Optical Coherence Tomography (SD-OCT) in non-glaucomatous subjects. Methods: The subjects were divided into three groups: low (n = 81, 35.6%), moderate (n = 79, 34.8%), and highly myopic eyes (n = 67, 29.5%). The RNFL thickness profile, including the average, superior, nasal, inferior, and temporal quadrant and each of the eight directional thicknesses, was measured. GCC parameters, including the average, superior, and inferior values, the focal loss volume (FLV), and the global loss volume (GLV), were measured. The correlation between the OCT measurements and the axial length was evaluated. Results: The average, superior, inferior, and nasal RNFL thicknesses of low and moderate myopic eyes were found to be significantly higher than those of highly myopic eyes. The temporal RNFL thicknesses were not different among the three groups. The average, superior, and inferior ganglion cell complex values of low and moderate myopic eyes were significantly higher than those of highly myopic eyes. The FLV and GLV of low and moderate myopic eyes were significantly higher than those of highly myopic eyes (p = 0.001 for all). In the moderate and high myopia groups, the average RNFL thickness and GCC thickness were both negatively correlated with the axial length. Conclusion: Highly myopic subjects tend to have thinner RNFL and GCC thicknesses than subjects with low and moderate myopia.     

妊娠高血压综合征患者共焦激光扫描炫彩眼底成像和光相干断层扫描图像特征

目的观察妊娠高血压综合征(PIHS)患者共焦激光扫描炫彩眼底成像(MSLI)和OCT图像特征。方法2016年5月至2017年5月于天津市第一中心医院产科确诊的PIHS患者112例224只眼纳入研究。患者平均年龄(27.00±2.14)岁。平均PIHS病程(15.00±8.27)d。自觉有视物模糊、眼花、视觉疲劳87例174只眼。均行BCVA、直接检眼镜、B型超声、共焦激光扫描检眼镜(cSLO)、频域OCT(SD-OCT)检查。采用德国Heidelberg公司Spectralis HRA+OCT仪行SD-OCT检查,采集断层扫描图像。应用基于cSLO的海德堡炫彩程序,按照标准方法进行操作,1次扫描同时获得基于488 nm的蓝光反射、515 nm绿光反射、820 nm红外反射成像,合成MSLI像。将眼底异常表现分为动脉痉挛期(Ⅰ期)、动脉硬化期(Ⅱ期)、视网膜病变期(Ⅲ期)。根据视网膜形态、厚度等有无异常分为表现正常和异常。结果224只眼中,直接检眼镜检查眼底表现正常68只眼(30.36%);眼底表现异常156只眼(69.64%)。其中,Ⅰ期28只眼(17.95%);Ⅱ期40只眼(25.64%);Ⅲ期88只眼(56.41%)。SD-OCT检查,眼底表现正常36只眼(16.07%);表现异常188只眼(83.93%)。眼底表现异常的188只眼中,视网膜神经上皮层浆液性脱离86只眼(45.74%);RPE层脱离56只眼(29.79%);视盘水肿、隆起及视网膜神经纤维层局部反射增强和(或)厚度增加等46只眼(24.47%)。MSLI像中,眼底表现正常48只眼(21.43%);表现异常176只眼(78.57%)。视网膜水肿、浆液性视网膜神经上皮层和RPE层脱离、视网膜神经纤维层增厚等伴有视网膜局部凸起结构改变在MSLI上以绿色呈现。凸起程度越高,颜色越深。与SD-OCT检查显示的视网膜水肿范围一致。结论PIHS患者MSLI与SD-OCT图像显示的病变高度一致;MSLI可更清晰显示视网膜浅层及深层病变。     

A Novel Technique of Adjusting Segmentation Boundary Layers to Achieve Comparability of Retinal Thickness and Volumes between Spectral Domain and Time Domain Optical Coherence Tomography

Purpose. The quantitative assessment of retinal thickness and volume varies according to the optical coherence tomography (OCT) machine used due to differences in segmentation lines. We describe a novel method of adjusting the segmentation lines of spectral-domain OCT (SD-OCT) to enable comparison with time-domain OCT (TD-OCT), and assess factors affecting its accuracy. Methods. In a prospective study, SD-OCT (Spectralis OCT) and TD-OCT (Stratus OCT) were sequentially performed on 200 eyes of 100 healthy individuals. Central retinal thickness (CRT), central point thickness (CPT), and 1-mm volume of the Early Treatment Diabetic Retinopathy Study grid were compared between the two machines. The segmentation lines on SD-OCT were manually adjusted by a trained operator and the parameters compared again with TD-OCT. Results. The mean CRTs of Spectralis and Stratus were significantly different (268.2 μm vs. 193.9 μm, P < 0.001). After adjustment of segmentation lines, the mean adjusted Spectralis CRT was 197.3 μm, with the difference between SD-OCT and TD-OCT measurements decreasing from 74.3 μm to 3.4 μm (P < 0.001). The difference between the adjusted Spectralis and Stratus CRTs was smallest for high myopes (≤ -6.0 diopters [D]) compared with those with moderate and low myopia (1.5 μm vs. 3.5 μm and 4.6 μm, respectively; P < 0.001). Similar trends were obtained for central 1-mm volumes and CPT. Interoperator and intraoperator repeatability for adjustment of the segmentation lines were good, with an intraclass correlation of 0.99 for both. Conclusions. Manual adjustment of SD-OCT segmentation lines reliably achieves retinal thickness and volume measurements that are comparable to that of TD-OCT. This is valuable to allow comparisons in multicenter clinical trials where different OCT machines may be used.     

The relationship between the optical density of cataract and its influence on retinal nerve fibre layer thickness measured with spectral domain optical coherence tomography

Purpose: The purpose of this study was to model the influence of cataract on Spectral Domain Optical Coherence Tomography (SDOCT) image quality and Retinal Nerve Fibre Layer (RNFL) thickness measurements. Methods: SDOCT images, made with two different devices (3DOCT‐1000, Topcon and Cirrus HD‐OCT), before and after cataract surgery were compared and judged against measurements from normal subjects using artificial filters simulating the effects of cataract. Optical density of the images was calculated based on a mathematical model described previously. Results: In total, forty‐eight eyes were included for pre‐ and postoperative cataract extraction measurements. OCT image quality significantly (p < 0.001) improved postoperative and postoperative RNFL thickness was significantly (p < 0.001) thicker in both groups of patients. The measurements using artificial filters showed a rather precise linear relation between change in filter induced optical density and change in RNFL thickness (R = 0.941, p < 0.001 for 3DOCT‐1000 and R = 0.785, p < 0.001 for Cirrus HD‐OCT). For the patient groups, the relation was less marked, 3DOCT‐1000 R_s = 0.697, p < 0.03 and Cirrus HD‐OCT R_s = 0.444, p < 0.03. The predictive potential based on the found linear relationship between OCT‐effective optical density of cataract and the cataract‐induced underestimation was however limited, and mean difference ± SD between predicted and measured RNFL thickness were 1.68 ± 7.55 (3DOCT‐1000) and 3.71 ± 2.97 (Cirrus HD‐OCT) micron. Conclusions: A linear relationship exists between OCT‐effective optical density of cataract and underestimation of RNFL thickness measured with OCT. This finding holds promise to correct for cataract‐induced changes in RNFL measurements, but will differ for each type of OCT device.     

Comparison of spectral domain and swept-source optical coherence tomography in pathological myopia

Purpose

To compare optical coherence tomography (OCT) images obtained with swept-source OCT (SS-OCT) and spectral domain OCT (SD-OCT) in pathological myopia.

Methods

This is a comparative observational cases series. Five patients with pathological myopia underwent SD-OCT and SS-OCT imaging. SS-OCT was performed using a prototype system (Topcon Medical Systems). SD-OCT was performed using enhanced depth imaging on the Heidelberg Spectralis OCT. The closest corresponding scans from the central subfield were compared.

Results

Eight eyes of five patients with pathological myopia were included (mean spherical equivalent: −16.00±4.70 D). Overall, SS-OCT better visualized retino-choroidal structures. The choroid, inner segment (IS)/outer segment (OS) line, and external limiting membrane (ELM) were clearly seen in a higher proportion of SS-OCT than SD-OCT scans, (P<0.01 for all) whereas visualization of the sclera and retinal pigment epithelium (RPE) were similar. SS-OCT demonstrated foveoschisis in four eyes, with one of these not visible on SD-OCT. The wider SS-OCT scan revealed additional pathology not visible using SD-OCT along the staphyloma walls in 4/8 images. These included incomplete posterior vitreous detachment in one eye and peripheral retinoschisis in 3/8 eyes. Vitreoschisis was visible in 3/8 SS-OCT images but not in the SD-OCT images.

Conclusion

SS-OCT is useful for imaging the posterior staphyloma of pathological myopia, providing greater detail than SD-OCT.     

视觉发育关键期大鼠视网膜频域OCT测量值的变化特征

背景人类和哺乳动物视觉发育关键期内视网膜处于发育阶段,其各个亚层的正确排列以及细胞的准确定位是视觉信息正常传递的基础之一。频域光学相关断层扫描（SD—OCT）可活体测量并连续观察大鼠视网膜厚度的变化。目的了解视觉发育关键期内SD大鼠视网膜厚度的变化规律。方法选择新生SD大鼠30只,其中10只于出生后14、18、21、24、42d进行双眼眼底SD—OCT扫描,对视网膜厚度以及部分亚层包括内界膜（ILM）至内丛状层（IPL）、内核层（INL）、外核层（ONL）至视网膜色素上皮（RPE）层的厚度进行生物测量。另取20只SD大鼠,分别于14、18、21、24、42d各处死4只大鼠并摘除双眼,制作石蜡切片行苏木精一伊红染色,对视网膜厚度以及部分亚层结构进行测量。并对两种方法测量数据的相关性进行评价。结果大鼠视网膜CirrusHD—OCT图像由内向外可显示视网膜IPL、INL、外丛状层（OPL）、ONL、光感受器内节／外节（IS／OS）层以及RPE层等结构。比较各个时间点的视网膜厚度、ILM至IPL厚度、INL厚度以及ONL至RPE层厚度,差异均有统计学意义（F=15．425,P=0．000;F=3．973,P=0．007;F=17．529,P：0．000;F=7．038,P=0．000）。随大鼠日龄的增加,视网膜厚度、INL厚度及ONL至RPE层厚度均呈递减趋势。测量视网膜组织切片各对应层次厚度,并与OCT测量结果进行线性回归分析,结果表明两种方法测量的视网膜厚度、INL厚度以及ONL至RPE层厚度均呈正相关（r=0．794,P=0．000;r=0．784,P=0．000;r=0．681,P=0．000）。结论CirrusHD—OCT可以清晰地显示并测量大鼠视网膜各主要层次,且与组织学测量具有较好的相关性。视觉发育关键期内大鼠视网膜逐渐变薄,OCT测量主要表现为INL厚度和ONL至RPE层厚度减少。