The visualization and assessment of retinal microvasculature are important in the study,diagnosis,monitoring,and guidance of treatment of ocular and systemic diseases.With the introduction of optical coherence tomogra...The visualization and assessment of retinal microvasculature are important in the study,diagnosis,monitoring,and guidance of treatment of ocular and systemic diseases.With the introduction of optical coherence tomography angiography(OCTA),it has become possible to visualize the retinal microvasculature volumetrically and without a contrast agent.Many lab-based and commercial clinical instruments,imaging protocols and data analysis methods and metrics,have been applied,often inconsistently,resulting in a confusing picture that represents a major barrier to progress in applying OCTA to reduce the burden of disease.Open data and software sharing,and cross-comparison and pooling of data from different studies are rare.These inabilities have impeded building the large databases of annotated OCTA images of healthy and diseased retinas that are necessary to study and define characteristics of specific conditions.This paper addresses the steps needed to standardize OCTA imaging of the human retina to address these limitations.Through review of the OCTA literature,we identify issues and inconsistencies and propose minimum standards for imaging protocols,data analysis methods,metrics,reporting of findings,and clinical practice and,where this is not possible,we identify areas that require further investigation.We hope that this paper will encourage the unification of imaging protocols in OCTA,promote transparency in the process of data collection,analysis,and reporting,and facilitate increasing the impact of OCTA on retinal healthcare delivery and life science investigations.展开更多
Background:To generate and validate a method to estimate axial length estimated(AL_(est))from spherical equivalent(SE)and corneal curvature[keratometry(K)],and to determine if this AL_(est)can replace actual axial len...Background:To generate and validate a method to estimate axial length estimated(AL_(est))from spherical equivalent(SE)and corneal curvature[keratometry(K)],and to determine if this AL_(est)can replace actual axial length(AL_(act))for correcting transverse magnification error in optical coherence tomography angiography(OCTA)images using the Littmann-Bennett formula.Methods:Data from 1301 participants of the Raine Study Gen2-20 year follow-up were divided into two datasets to generate(n=650)and validate(n=651)a relationship between AL,SE,and K.The developed formula was then applied to a separate dataset of 46 participants with AL,SE,and K measurements and OCTA images to estimate and compare the performance of AL_(est)against AL_(act)in correcting transverse magnification error in OCTA images when measuring the foveal avascular zone area(FAZA).Results:The formula for AL_(est)yielded the equation:AL_(est)=2.102K−0.4125SE+7.268,R^(2)=0.794.There was good agreement between AL_(est)and AL_(act)for both study cohorts.The mean difference[standard deviation(SD)]between FAZA corrected with AL_(est)and AL_(act)was 0.002(0.015)mm^(2)with the 95%limits of agreement(LoA)of−0.027 to 0.031 mm^(2).In comparison,mean difference(SD)between FAZA uncorrected and corrected with AL_(act)was−0.005(0.030)mm^(2),with 95%LoA of−0.064 to 0.054 mm^(2).Conclusions:AL_(act)is more accurate than AL_(est)and hence should be used preferentially in magnification error correction in the clinical setting.FAZA corrected with AL_(est)is comparable to FAZA corrected with AL_(act),while FAZA measurements using images corrected with AL_(est)have a greater accuracy than measurements on uncorrected images.Hence,in the absence of AL_(act),clinicians should use AL_(est)to correct for magnification error as this provides for more accurate measurements of fundus parameters than uncorrected images.展开更多
基金the Australian National Health&Medical Research Council(project and fellowship grant no.:GNT1116360,GNT1188694,GNT1054712,and MRF1142962)the Raine Foundation,Ophthalmic Research Institute of Australia,and the McCusker Charitable Foundation for his and his team's work in OCTA.
文摘The visualization and assessment of retinal microvasculature are important in the study,diagnosis,monitoring,and guidance of treatment of ocular and systemic diseases.With the introduction of optical coherence tomography angiography(OCTA),it has become possible to visualize the retinal microvasculature volumetrically and without a contrast agent.Many lab-based and commercial clinical instruments,imaging protocols and data analysis methods and metrics,have been applied,often inconsistently,resulting in a confusing picture that represents a major barrier to progress in applying OCTA to reduce the burden of disease.Open data and software sharing,and cross-comparison and pooling of data from different studies are rare.These inabilities have impeded building the large databases of annotated OCTA images of healthy and diseased retinas that are necessary to study and define characteristics of specific conditions.This paper addresses the steps needed to standardize OCTA imaging of the human retina to address these limitations.Through review of the OCTA literature,we identify issues and inconsistencies and propose minimum standards for imaging protocols,data analysis methods,metrics,reporting of findings,and clinical practice and,where this is not possible,we identify areas that require further investigation.We hope that this paper will encourage the unification of imaging protocols in OCTA,promote transparency in the process of data collection,analysis,and reporting,and facilitate increasing the impact of OCTA on retinal healthcare delivery and life science investigations.
文摘Background:To generate and validate a method to estimate axial length estimated(AL_(est))from spherical equivalent(SE)and corneal curvature[keratometry(K)],and to determine if this AL_(est)can replace actual axial length(AL_(act))for correcting transverse magnification error in optical coherence tomography angiography(OCTA)images using the Littmann-Bennett formula.Methods:Data from 1301 participants of the Raine Study Gen2-20 year follow-up were divided into two datasets to generate(n=650)and validate(n=651)a relationship between AL,SE,and K.The developed formula was then applied to a separate dataset of 46 participants with AL,SE,and K measurements and OCTA images to estimate and compare the performance of AL_(est)against AL_(act)in correcting transverse magnification error in OCTA images when measuring the foveal avascular zone area(FAZA).Results:The formula for AL_(est)yielded the equation:AL_(est)=2.102K−0.4125SE+7.268,R^(2)=0.794.There was good agreement between AL_(est)and AL_(act)for both study cohorts.The mean difference[standard deviation(SD)]between FAZA corrected with AL_(est)and AL_(act)was 0.002(0.015)mm^(2)with the 95%limits of agreement(LoA)of−0.027 to 0.031 mm^(2).In comparison,mean difference(SD)between FAZA uncorrected and corrected with AL_(act)was−0.005(0.030)mm^(2),with 95%LoA of−0.064 to 0.054 mm^(2).Conclusions:AL_(act)is more accurate than AL_(est)and hence should be used preferentially in magnification error correction in the clinical setting.FAZA corrected with AL_(est)is comparable to FAZA corrected with AL_(act),while FAZA measurements using images corrected with AL_(est)have a greater accuracy than measurements on uncorrected images.Hence,in the absence of AL_(act),clinicians should use AL_(est)to correct for magnification error as this provides for more accurate measurements of fundus parameters than uncorrected images.
