1. Articles from Rohit Varma

    1-23 of 23
    1. Effect of Scan Size on Glaucoma Diagnostic Performance Using OCT Angiography En Face Images of the Radial Peripapillary Capillaries

      Effect of Scan Size on Glaucoma Diagnostic Performance Using OCT Angiography En Face Images of the Radial Peripapillary Capillaries

      Precis: When comparing 4.5×4.5 mm to 6.0×6.0 mm optical coherence tomography angiography scans of the radial peripapillary capillaries (RPCs) for glaucoma diagnostic capability, there was a trend of 4.5 scans outperforming 6.0 scans, especially for inferior, nasal, and superior quadrants. Objectives: The main purpose of this study was to compare diagnostic ability of peripapillary vessel parameters from 4.5×4.5 mm (4.5) and 6.0×6.0 mm (6.0) spectral-domain optical coherence tomography angiography scans of the RPC in detecting primary open-angle glaucoma from nonglaucoma eyes. Methods: Consecutive patients ...

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    2. Quantitative Evaluation of Gonioscopic and EyeCam Assessments of Angle Dimensions Using Anterior Segment Optical Coherence Tomography

      Quantitative Evaluation of Gonioscopic and EyeCam Assessments of Angle Dimensions Using Anterior Segment Optical Coherence Tomography

      Purpose : To evaluate the relationship between angle dimensions assessed by gonioscopy or EyeCam and anterior segment optical coherence tomography (AS-OCT). Methods : Subjects aged 50 years or older were recruited from the Chinese American Eye Study (CHES). Each subject underwent a complete ocular exam, including gonioscopy, AS-OCT, and EyeCam. Angle closure was defined as three or more quadrants in which pigmented trabecular meshwork could not be visualized. Angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular iris angle (TIA), and scleral spur angle (SSA) were measured in each AS-OCT image. Results : 709 eyes (272 angle closure ...

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    3. Diagnostic Performance of Macular Versus Peripapillary Vessel Parameters by Optical Coherence Tomography Angiography for Glaucoma

      Diagnostic Performance of Macular Versus Peripapillary Vessel Parameters by Optical Coherence Tomography Angiography for Glaucoma

      Purpose : To compare the diagnostic ability of the vessel parameters in macular and peripapillary regions measured using spectral-domain optical coherence tomography angiography (SD-OCTA) in differentiating primary open-angle glaucoma (POAG) from healthy eyes. Methods : POAG patients and healthy subjects underwent 6 × 6-mm scans centered on the macula and optic nerve head. Commercially available automatic segmentation created en face images from SD-OCTA of the superficial retinal layer (SRL) of the macular (m) and peripapillary (cp) regions. Vessel area density (VAD), vessel skeleton density (VSD), vessel complexity index (VCI), and flux were calculated. Area under curve (AUC) statistics controlled for age and intereye ...

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    4. Peripapillary microvasculature in the retinal nerve fiber layer in glaucoma by optical coherence tomography angiography: focal structural and functional correlations and diagnostic performance

      Peripapillary microvasculature in the retinal nerve fiber layer in glaucoma by optical coherence tomography angiography: focal structural and functional correlations and diagnostic performance

      Purpose: To quantify peripapillary microvasculature within the retinal nerve fiber layer (RNFL) in primary open-angle glaucoma (POAG) and normal eyes, determine association of perfusion parameters with structural and functional measures, and report diagnostic accuracy of perfusion parameters. Patients and methods: POAG and normal patients underwent 6×6 mm2 optic nerve head scans (Angioplex optical coherence tomography angiography [OCTA]; Cirrus HD-OCT 5000) and Humphrey Field Analyzer II-i 24-2 visual field (VF) testing. Prototype software performed semiautomatic segmentation to create RNFL en face images and quantified vessel area density (VAD), vessel skeleton density (VSD), and vessel complexity index (VCI) in the optic ...

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    5. Correlation Between Intraocular Pressure and Angle Configuration Measured by Optical Coherence Tomography: The Chinese American Eye Study

      Correlation Between Intraocular Pressure and Angle Configuration Measured by Optical Coherence Tomography: The Chinese American Eye Study

      PURPOSE To characterize the relationship between angle configuration measured by anterior segment optical coherence tomography (AS-OCT) and intraocular pressure (IOP). DESIGN Cross-sectional study. PARTICIPANTS Subjects aged 50 years or older were identified from the Chinese American Eye Study (CHES), a population-based epidemiological study in Los Angeles, CA. METHODS Each subject underwent a complete ocular exam including Goldmann applanation tonometry, gonioscopy, and AS-OCT imaging. Four AS-OCT images were analyzed per eye and parameters describing angle configuration were measured, including angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular iris angle (TIA), and scleral spur angle (SSA ...

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      Mentions: Rohit Varma UCLA
    6. Comparison of Glaucoma Progression Detection by Optical Coherence Tomography and Visual Field

      Comparison of Glaucoma Progression Detection by Optical Coherence Tomography and Visual Field

      Purpose To compare longitudinal glaucoma progression detection using optical coherence tomography (OCT) and visual field (VF). Design Validity assessment Method We analyzed subjects with more than 5 follow-up visits (every 6 months) in the multi-center Advanced Imaging for Glaucoma Study. Fourier-domain optical coherence tomography (OCT) was used to map the thickness of the peripapillary retinal nerve fiber layer (NFL) and ganglion cell complex (GCC). OCT-based progression detection was defined as a significant negative trend for either NFL or GCC. VF progression was reached if either the event or trend analysis reached significance. Result The analysis included 417 glaucoma suspect/pre-perimetric ...

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    7. Benefit of Measuring Anterior Segment Structures Using an Increased Number of Optical Coherence Tomography Images: The Chinese American Eye Study

      Benefit of Measuring Anterior Segment Structures Using an Increased Number of Optical Coherence Tomography Images: The Chinese American Eye Study

      Purpose : The purpose of this study was to evaluate the benefit of analyzing an increased number of anterior segment optical coherence tomography (AS-OCT) images on measurement values of various anterior segment parameters. Methods : Subjects for this cross-sectional study were recruited from the Chinese American Eye Study (CHES), a population-based study in Los Angeles, CA. Thirty-two AS-OCT images were acquired from one eye each of 83 consecutive subjects. Sixteen parameters were analyzed in each image, including angle opening distance (AOD), angle recess area (ARA), trabecular iris space area (TISA), trabecular iris angle (TIA), scleral spur angle (SSAngle), lens vault (LV), pupillary ...

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      Mentions: Rohit Varma UCLA
    8. Longitudinal and Cross-Sectional Analyses of Age and Intraocular Pressure Effects on Retinal Nerve Fiber Layer and Ganglion Cell Complex Thickness

      Longitudinal and Cross-Sectional Analyses of Age and Intraocular Pressure Effects on Retinal Nerve Fiber Layer and Ganglion Cell Complex Thickness

      Purpose : To study the effect of age and intraocular pressure (IOP) on retinal nerve fiber layer (NFL) and ganglion cell complex (GCC) thickness in normal eyes. Methods : We analyzed the data from subjects enrolled in the multi-center longitudinal Advanced Imaging for Glaucoma (AIG) Study (www.AIGStudy.net). The data included yearly visits from the normal subjects group in the AIGS study. Fourier-domain optical coherence tomography (OCT) was used to map the thickness of NFL and GCC three times on each visit. To adjust for the repeated measurements for the same subjects, mixed effect models were used to evaluate the longitudinal ...

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    9. Regression Analysis of Optical Coherence Tomography Disc Variables for Glaucoma Diagnosis

      Regression Analysis of Optical Coherence Tomography Disc Variables for Glaucoma Diagnosis

      Purpose: To report diagnostic accuracy of optical coherence tomography (OCT) disc variables using both time-domain (TD) and Fourier-domain (FD) OCT, and to improve the use of OCT disc variable measurements for glaucoma diagnosis through regression analyses that adjust for optic disc size and axial length-based magnification error. Design: Observational, cross-sectional. Participants: In total, 180 normal eyes of 112 participants and 180 eyes of 138 participants with perimetric glaucoma from the Advanced Imaging for Glaucoma Study. Methods: Diagnostic variables evaluated from TD-OCT and FD-OCT were: disc area, rim area, rim volume, optic nerve head volume, vertical cup-to-disc ratio (CDR), and horizontal ...

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    10. Predicting Development of Glaucomatous Visual Field Conversion Using Baseline Fourier-Domain Optical Coherence Tomography

      Predicting Development of Glaucomatous Visual Field Conversion Using Baseline Fourier-Domain Optical Coherence Tomography

      Purpose To predict the development of glaucomatous visual field (VF) defects using Fourier-domain optical coherence tomography (FD-OCT) measurements at baseline visit. Design Multi-center longitudinal observational study. Glaucoma suspects and pre-perimetric glaucoma participants in the Advanced Imaging for Glaucoma Study. Methods The optic disc, the peripapillary retinal nerve fiber layer (NFL), and macular ganglion cell complex (GCC) were imaged with FD-OCT VF was assessed every 6 months. Conversion to perimetric glaucoma was defined by VF pattern standard deviation (PSD) or glaucoma hemifield test (GHT) outside normal limits on 3 consecutive tests. Hazard ratios were calculated with the Cox proportional hazard model ...

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    11. Combining measurements from three anatomical areas for glaucoma diagnosis using Fourier-domain optical coherence tomography

      Combining measurements from three anatomical areas for glaucoma diagnosis using Fourier-domain optical coherence tomography

      Aims To improve the diagnostic power for glaucoma by combining measurements of peripapillary nerve fibre layer (NFL), macular ganglion cell complex (GCC) and disc variables obtained with Fourier-domain optical coherence tomography (FD-OCT) into the glaucoma structural diagnostic index (GSDI). Methods In this observational, cross-sectional study of subjects from the Advanced Imaging of Glaucoma Study, GCC and NFL of healthy and perimetrical glaucoma subjects from four major academic referral centres of the Advanced Imaging of Glaucoma Study were mapped with the RTVue FD-OCT. Global loss volume and focal loss volume parameters were defined using NFL and GCC normative reference maps. Optimal ...

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    12. Measurement of retinal blood flow in normal Chinese American subjects by Doppler Fourier-domain optical coherence tomography

      Measurement of retinal blood flow in normal Chinese American subjects by Doppler Fourier-domain optical coherence tomography

      PURPOSE: To measure total retinal blood flow (TRBF) in normal, healthy Chinese-Americans using semi-automated analysis of Doppler Fourier-domain optical coherence tomography (FD-OCT) scans. METHODS: Two hundred sixty-six normal, healthy Chinese-American participants (266 eyes) were enrolled from The Chinese American Eye Study (CHES). All participants underwent complete ophthalmic examination, including best-corrected visual acuity, indirect ophthalmoscopy and Doppler FD-OCT imaging, using the circumpapillary double circular scan protocol. TRBF and other vascular parameters (e.g. venous and arterial cross-sectional area and their velocities) were calculated using Doppler OCT of Retinal Circulation software. Associations between TRBF and other clinical parameters were assessed using bivariate ...

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    13. Advanced Imaging for Glaucoma Study: Design, Baseline Characteristics, and Inter-Site Comparison

      Advanced Imaging for Glaucoma Study: Design, Baseline Characteristics, and Inter-Site Comparison

      Purpose To report the baseline characteristics of the participants in the Advanced Imaging for Glaucoma Study. To compare the participating sites for variations among subjects and the performance of imaging instruments. Design Multi-center longitudinal observational cohort study Methods A total of 788 participants (1,329 eyes) were enrolled from three academic referral centers. There were 145 participants (289 eyes) in the normal group, 394 participants (663 eyes) in the glaucoma suspect/preperimetric glaucoma group, and 249 participants (377 eyes) in the perimetric glaucoma group. Participants underwent a full clinical exam, standard automated perimetry, and imaging with time-domain and Fourier-domain optical ...

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    14. Combining Information From 3 Anatomic Regions in the Diagnosis of Glaucoma With Time-Domain Optical Coherence Tomography

      Combining Information From 3 Anatomic Regions in the Diagnosis of Glaucoma With Time-Domain Optical Coherence Tomography

      Purpose: To improve the diagnosis of glaucoma by combining time-domain optical coherence tomography (TD-OCT) measurements of the optic disc, circumpapillary retinal nerve fiber layer (RNFL), and macular retinal thickness. Patients and Methods: Ninety-six age-matched normal and 96 perimetric glaucoma participants were included in this observational, cross-sectional study. Or-logic, support vector machine, relevance vector machine, and linear discrimination function were used to analyze the performances of combined TD-OCT diagnostic variables. Results: The area under the receiver-operating curve (AROC) was used to evaluate the diagnostic accuracy and to compare the diagnostic performance of single and combined anatomic variables. The best RNFL thickness ...

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    15. Does optic nerve head size variation affect circumpapillary retinal nerve fiber layer thickness measurement by optical coherence tomography?

      Does optic nerve head size variation affect circumpapillary retinal nerve fiber layer thickness measurement by optical coherence tomography?

      Purpose: To determine the relationship between retinal nerve fiber layer (RNFL) thickness, optic disc size and image magnification. Methods: The cohort consisted of 196 normal eyes of 101 participants in the Advanced Imaging for Glaucoma Study (AIGS), a multi-center, prospective, longitudinal study to develop advanced imaging technologies for glaucoma diagnosis. Scanning laser tomography (HRT II) was used to measure disc size. Optical coherence tomography (Stratus) was used to perform circumpapillary RNFL thickness measurements using the standard fixed 3.46 mm nominal scan diameter. A theoretical model of magnification effects was developed to relate RNFL thickness (overall average) with axial length ...

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    16. Relationship among visual field, blood flow, and neural structure measurements in glaucoma

      Relationship among visual field, blood flow, and neural structure measurements in glaucoma

      Purpose:To determine the relationship among visual field, neural structural, and blood flow measurements in glaucoma. Methods:Case-control study. Forty-seven eyes of 42 patients with perimetric glaucoma were age-matched with 27 normal eyes of 27 patients. All patients underwent Doppler Fourier-domain optical coherence tomography to measure retinal blood flow and standard glaucoma evaluation with visual field testing and quantitative structural imaging. Linear regression analysis was performed to analyze the relationship among visual field, blood flow, and structure, after all variables were converted to logarithmic decibel scale. Results:Retinal blood flow was reduced in glaucoma eyes compared to normal eyes (p

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    17. Variation in Optic Nerve and Macular Structure with Age and Race with Spectral-Domain Optical Coherence Tomography

      Variation in Optic Nerve and Macular Structure with Age and Race with Spectral-Domain Optical Coherence Tomography
      Purpose: To evaluate the effects of age and race on optic disc, retinal nerve fiber layer, and macular measurements with spectral-domain optical coherence tomography (SD OCT).Design: Cross-sectional observational study.Participants: Three hundred fifty adult subjects without ocular disease.Methods: Data from SD OCT imaging of the optic nerve head, peripapillary retinal nerve fiber layer (RNFL), and macula of 632 eyes from 350 subjects without ocular disease were imaged with SD OCT. Multivariate models were used to determine the effect of age and race on quantitative measurements of optic disc, RNFL, and macula.Main Outcome Measures: Optic nerve, RNFL, and ...
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    18. Pilot Study of Optical Coherence Tomography Measurement of Retinal Blood Flow in Retinal and Optic Nerve Diseases

      Pilot Study of Optical Coherence Tomography Measurement of Retinal Blood Flow in Retinal and Optic Nerve Diseases
      Purpose: To investigate blood flow changes in retinal and optic nerve diseases with Doppler Fourier domain optical coherence tomography (OCT). Methods: Sixty-two participants were divided into five groups: normal, glaucoma, nonarteritic ischemic optic neuropathy (NAION), treated proliferative diabetic retinopathy (PDR), and branch retinal vein occlusion (BRVO). Doppler OCT was used to scan concentric circles of 3.4 and 3.75 mm diameters around the optic nerve head. Flow in retinal veins were calculated from the OCT velocity profiles. Arterial and venous diameters were measured from OCT Doppler and reflectance images. Results: Total retinal blood flow in normal subjects averaged 47 ...
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    19. Topographic Differences in the Age-related Changes in the Retinal Nerve Fiber Layer of Normal Eyes Measured by Stratus Optical Coherence Tomography

      Topographic Differences in the Age-related Changes in the Retinal Nerve Fiber Layer of Normal Eyes Measured by Stratus Optical Coherence Tomography
      Purpose: To determine whether there are regional differences in the age-related changes in peripapillary retinal nerve fiber layer (RNFL) thickness as measured by time-domain optical coherence tomography (OCT). Methods: Fast peripapillary RNFL scans obtained with the Stratus time-domain OCT with nominal diameter of 3.46-mm centered on the optic disc were carried out on 425 normal participants over a wide age range. One eye was randomly selected for scanning or analysis. Average RNFL-, clock hour-, and quadrant-specific rates of RNFL thickness change were calculated and compared. Results: The 425 study participants ranged in age from 18 to 85 years with ...
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    20. Optic Nerve Head (ONH) Topographic Analysis by Stratus OCT in Normal Subjects: Correlation to Disc Size, Age, and Ethnicity

      Purpose: To study optic nerve head (ONH) topography parameters measured by Stratus optical coherence tomography (OCT) in normal subjects and to analyze ONH data for differences in relation to disc size, ethnicity, and age. Methods: Three hundred sixty-seven normal subjects underwent Stratus optical coherence tomography ONH measurement using the fast optic disc scan protocol software package 3.0. Only ONH scans meeting specific qualification criteria were included for data analysis ensuring appropriate scan quality and reliability. ONH topographic parameters of qualified scans were analyzed for differences in regards to optic disc size, age, and ethnicity. Results: Two hundred and twelve ...
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    21. Detection of Macular Ganglion Cell Loss in Glaucoma by Fourier-Domain Optical Coherence Tomography

      Detection of Macular Ganglion Cell Loss in Glaucoma by Fourier-Domain Optical Coherence Tomography
      Purpose: To map ganglion cell complex (GCC) thickness with high-speed Fourier-domain optical coherence tomography (FD-OCT) and compute novel macular parameters for glaucoma diagnosis.Design: Observational, cross-sectional study.Participants: One hundred seventy-eight participants in the Advanced Imaging for Glaucoma Study, divided into 3 groups: 65 persons in the normal group, 78 in the perimetric glaucoma group (PG), and 52 in the preperimetric glaucoma group (PPG).Methods: The RTVue FD-OCT system was used to map the macula over a 7×6 mm region. The macular OCT images were exported for automatic segmentation using software we developed. The program measured macular retinal (MR ...
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    22. Combining Nerve Fiber Layer Parameters to Optimize Glaucoma Diagnosis with Optical Coherence Tomography

      Purpose To identify the best combination of Stratus optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness parameters for the detection of glaucoma. Design Observational cross-sectional study. Participants Eighty-nine age-matched normal and perimetric glaucoma participants enrolled in the Advanced Imaging for Glaucoma Study. Methods The Zeiss Stratus OCT system was used to obtain the circumpapillary RNFL thickness in both eyes of each participant. Right and left eye clock-hour data are analyzed together, assuming mirror-image symmetry. The RNFL diagnostic parameters were combined using either or-logic or and-logic approaches. Main Outcome Measures Area under the receiver operating characteristic curve (AROC), sensitivity ...
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    23. Glaucoma diagnosis by mapping macula with Fourier domain optical coherence tomography

      Ou Tan, Ake Lu, Vik Chopra et al. A new image segmentation method was developed to detect macular retinal sub-layers boundary on newly-developed Fourier-Domain Optical Coherence Tomography (FD-OCT) with macular grid scan pattern. The segmentation results were used to create thickness map of macular ganglion cell complex (GCC), which ... [Proc. SPIE Int. Soc. Opt. Eng. 6915, 69153L (2008)] published Mon Mar 17, 2008.
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    1-23 of 23
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