1. Articles from iovs.org

  2. 241-264 of 560 « 1 2 ... 8 9 10 11 12 13 14 ... 22 23 24 »
    1. Detection of Glaucoma Progression by Assessment of Segmented Macular Thickness Data Obtained Using Spectral Domain Optical Coherence Tomography

      Detection of Glaucoma Progression by Assessment of Segmented Macular Thickness Data Obtained Using Spectral Domain Optical Coherence Tomography

      Purpose: To evaluate the clinical utility of segmented macular layer thickness measurement in terms of both glaucoma diagnosis and the ability to detect progression, and to compare such outcomes with those by circumpapillary retinal nerve fiber layer (cRNFLT) and total macular thickness (TMT) measurements. Methods: One-hundred-and-forty-one glaucomatous and 61 healthy eyes were included. All glaucomatous eyes were subjected to at least four spectral domain optical coherence tomography (SD-OCT) examinations (mean follow-up; 2.13 years). Segmented macular layers were the macular NFL, GCA (ganglion cell and inner plexiform layer), and outer retinal layer (ORL; from outer plexiform layer to retinal pigment ...

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    2. Long-Term Characterization of Retinal Degeneration in rd1 and rd10 Mice Using Spectral Domain Optical Coherence Tomography

      Long-Term Characterization of Retinal Degeneration in rd1 and rd10 Mice Using Spectral Domain Optical Coherence Tomography

      Purpose. To characterize the in vivo changes over time in the retinal structure of wild-type mice alongside two lines of mice deficient in the ß-subunit of phosphodiesterase (rd1 and rd10 mice) using Spectral Domain Optical Coherence Tomography (SD-OCT). Methods. SD-OCT images were obtained using the Bioptigen Spectral Domain Ophthalmic Imaging System (SDOIS). Wild-type C57BL/6J, rd1 and rd10 mice ranging in age from P14 to P206 were sedated with 1% isoflurane. Horizontal and vertical linear scans through the optic nerve and annular scans around the optic nerve were obtained. Results. SD-OCT imaging of wild-type mice demonstrated visibility of the inner ...

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    3. In Vivo Human Choroidal Vascular Pattern Visualization Using High-Speed Swept-Source Optical Coherence Tomography at 1060 nm

      In Vivo Human Choroidal Vascular Pattern Visualization Using High-Speed Swept-Source Optical Coherence Tomography at 1060 nm

      Purpose. To investigate the retinal and choroidal vascular pattern, structure, and thickness using high-speed, high axial resolution, swept-source optical coherence tomography (SS-OCT) at 1060 nm, demonstrating enhanced penetration through all choroidal layers. Methods. An ophthalmic SS-OCT system was developed operating at 57,000 A-lines/s with 5.9 μm axial resolution and was used to collect 3D images with scanning angles up to ~70° x 35°. The similar features were observed in the choroidal layers by imaging three healthy volunteers. En face images, extracted at different depths, capture features of the retinal and choroidal vasculature networks and substructure. Retinal and ...

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    4. Comparison of Retinal Nerve Fiber Layer Thickness Measurement Bias and Imprecision Across Three Spectral-Domain Optical Coherence Tomography Devices

      Comparison of Retinal Nerve Fiber Layer Thickness Measurement Bias and Imprecision Across Three Spectral-Domain Optical Coherence Tomography Devices

      Purpose: To compare retinal nerve fiber layer (RNFL) bias and imprecision amongst three spectral-domain optical coherence tomographs (SD-OCT). Methods: 152 eyes of 83 subjects (96 healthy and 56 glaucomatous eyes) underwent peripapillary RNFL imaging using at least 2 of the following 3 SD-OCT devices on the same day: Cirrus HD-OCT (optic nerve head (ONH) cube 200x200 protocol), RTVue-100 (ONH protocol (12 radial lines and 13 concentric circles), and 3D OCT-1000 (3D Scan 256x256 protocol). Calibration equations, bias and imprecision of RNFL measurements were calculated using structural equation models. Results: The calibration equations for healthy and glaucoma RNFL thickness measurements among ...

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    5. Assessment of Macular Function for Idiopathic Epiretinal Membranes Classified by Spectral Domain Optical Coherence Tomography

      Assessment of Macular Function for Idiopathic Epiretinal Membranes Classified by Spectral Domain Optical Coherence Tomography

      Purpose: To evaluate the functional changes in various morphologic types of idiopathic epiretinal membrane (ERM) by multifocal electroretinography (mfERG) and spectral domain optical coherence tomography (SD-OCT). Methods: All patients (n=71) with unilateral idiopathic ERM underwent complete ophthalmological examination, including measurements of best-corrected visual acuity (BCVA), SD-OCT, and mfERG for both eyes. To classify idiopathic ERM by subtype, the morphologic characteristics of the foveal area on representative scanned images were assessed. The 5 subtypes by foveal SD-OCT morphology included fovea-attached ERM with outer retinal thickening and minimal inner retinal change (Group 1A), outer retinal inward projection and inner retinal thickening ...

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    6. Agreement of retinal nerve fiber layer color codes between Stratus and Cirrus OCT according to glaucoma severity

      Agreement of retinal nerve fiber layer color codes between Stratus and Cirrus OCT according to glaucoma severity

      Purpose: To assess the agreement of retinal nerve fiber layer (RNFL) color codes between Stratus and Cirrus optical coherence tomography (OCT) according to the glaucoma severity. Methods: A total of 184 eyes from 144 subjects with glaucoma and 40 normal subjects were analyzed. Glaucoma was categorized into three subgroups according to mean deviation of visual field. The agreement of RNFL color code according to the glaucoma severity was assessed using Cohen's kappa value. Red or yellow color codes were defined as abnormal results while green or white were defined as normal. Disagreement frequency of abnormal color code displayed by ...

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    7. Morphometric Analysis of Aqueous Humor Outflow Structures with Spectral Domain Optical Coherence Tomography

      Morphometric Analysis of Aqueous Humor Outflow Structures with Spectral Domain Optical Coherence Tomography

      Purpose: To describe morphometric details of the human aqueous humor (AH) outflow microvasculature visualized with 360 degree virtual castings during active AH outflow in cadaver eyes and comparing these structures with corrosion casting studies. Methods: The conventional AH outflow pathways of donor eyes (N=7) and eyes in vivo (N=3) were imaged with spectral-domain optical coherence tomography (SD-OCT) and wide-bandwidth super luminescent diode array during active AH outflow. Digital image contrast was adjusted to isolate AH microvasculature and images were viewed in a 3D viewer. Additional eyes (N=3) were perfused with mock AH containing fluorescent tracer microspheres to ...

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    8. Factors associated with anterior chamber narrowing with age: an optical coherence tomography study

      Factors associated with anterior chamber narrowing with age: an optical coherence tomography study

      Purpose: To evaluate the effect of age on various anterior segment (AS) parameters in healthy eyes using AS optical coherence tomography (OCT), and to examine their relationship to anterior chamber angle (ACA) narrowing with age. Methods: Three hundred-and-eighty-eight consecutive Korean subjects aged 30 to 89 years were imaged by AS OCT (Visante, version 2.0; Carl Zeiss Meditec, Dublin, CA). Anterior chamber depth (ACD), iris cross-sectional area (IA), iris thickness at 750 and 1,500 microns from the scleral spur (IT750, 1500), iris curvature (IC), lens vault (LV), and anterior chamber area (AA) were determined using Image J software (version ...

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    9. 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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    10. Structure-Function Relationships between Spectral-Domain OCT and Standard Achromatic Perimetry

      Structure-Function Relationships between Spectral-Domain OCT and Standard Achromatic Perimetry

      Purpose: To explore structure-function relationships in early glaucoma with spectral-domain optical coherence tomography (SD-OCT) and standard achromatic perimetry. Methods: One hundred thirty-six eyes of 97 patients with suspected or early glaucoma were enrolled from the clinical database at UCLA's Glaucoma Division. All patients had good-quality peripapillary retinal nerve fiber layer (RNFL)/optic disc measurements (Optic Disc Cube 200x200, Cirrus HD-OCT) and a reliable 24-2 SITA-Standard Humphrey visual field (VF) within a 6-month period. Correlations of global and sectoral RNFL thickness and rim area (RA) measurements with corresponding global and regional VF sensitivities (both in logarithmic [dB] and 1/Lambert ...

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    11. Scanning Laser Polarimetry Reveals Status of Retinal Nerve Fiber Layer (RNFL) Integrity in Eyes with Optic Nerve Head Swelling by OCT

      Scanning Laser Polarimetry Reveals Status of Retinal Nerve Fiber Layer (RNFL) Integrity in Eyes with Optic Nerve Head Swelling by OCT

      Purpose OCT shows retinal nerve fiber layer (RNFL) thickening in optic nerve head (ONH) swelling, but does not provide information on acute axonal disruption. We hypothesized that scanning laser polarimetry (SLP) in comparison with OCT might reveal the status of axon integrity and visual prognosis in acute RNFL swelling. Methods We used threshold perimetry, OCT, and SLP to prospectively study eyes with papilledema (24), optic neuritis (13), NAION (21), and ONH swelling (defined as having average RNFL by OCT > 95th percentile of controls at presentation). Regional RNFL was judged reduced if the OCT or SLP measure in a quadrant was < 5th percentile of controls. Results At presentation, average RNFL by OCT was similar for eyes with papilledema and NAION (p=0.97), and less for optic neuritis. Average RNFL by SLP was less often increased, similar for papilledema and optic neuritis, but less for NAION (p=0.02) eyes. The RNFL by SLP was reduced in at least 1 quadrant in 1/24 eyes with papilledema, 1/14 eyes with optic neuritis, and in 13/21 eyes with NAION. In NAION eyes, quadrants with reduced SLP had corresponding visual field loss that did not recover at 1 or 6 months. By 1 month, eyes with NAION showed RNFL thinning by OCT (7/17 eyes) and by SLP in14/16 eyes) in contrast to optic neuritis (by OCT, 0/12; p=0.006 and by SLP, 1/12; p=0.0004). Conclusion OCT and SLP reveal different aspects of RNFL changes associated with ONH swelling. OCT reveals thickening, due to edema. SLP reveals a decrease in retardance in eyes with axonal injury associated with visual field loss, which is unlikely to recover. This study provides evidence that SLP may be predictive of regions of permanent axon dysfunction and visual field loss in eyes with optic disc edema.

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    12. Optical Coherence Tomography as a Rapid, Accurate, Noncontact Method of Visualizing the Palisades of Vogt

      Optical Coherence Tomography as a Rapid, Accurate, Noncontact Method of Visualizing the Palisades of Vogt

      Purpose. This study explored the efficacy of optical coherence tomography (OCT) as a high-resolution, noncontact method for imaging the palisades of Vogt by correlating OCT and confocal microscopy images. Methods. Human limbal rims were acquired and imaged with OCT and confocal microscopy. The area of the epithelial basement membrane in each of these sets was digitally reconstructed, and the models were compared. Results. OCT identified the palisades within the limbus and exhibited excellent structural correlation with immunostained tissue imaged by confocal microscopy. Conclusions. OCT successfully identified the limbal palisades of Vogt that constitute the corneal epithelial stem cell niche. These ...

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    13. Signal quality assessment of retinal optical coherence tomography (OCT) images

      Signal quality assessment of retinal optical coherence tomography (OCT) images

      Purpose: To assess signal quality of retinal OCT images from multiple devices using subjective and quantitative measurements. Methods: 120 multi-frame OCT images from 4 SD OCT devices (Cirrus, RTVue, Spectralis, and 3D OCT-1000) were evaluated subjectively by trained graders, and measured quantitatively using a derived parameter, maximum tissue contrast index (mTCI). An intensity histogram decomposition model was proposed to separate the foreground and background information of OCT images and to calculate the mTCI. The mTCI results were compared to the manufacturer signal index (MSI) provided by the respective devices, and to the subjective grading scores (SGS). Results: Statistically significant correlations ...

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    14. The Effect of Glaucoma on the Optical Attenuation Coefficient of the Retinal Nerve Fiber Layer in Spectral Domain Optical Coherence Tomography Images

      The Effect of Glaucoma on the Optical Attenuation Coefficient of the Retinal Nerve Fiber Layer in Spectral Domain Optical Coherence Tomography Images

      Purpose: To demonstrate the effect of glaucoma on the optical attenuation coefficient of the retinal nerve fiber layer (RNFL) in Spectral Domain Optical Coherence Tomography (SD-OCT) images. Methods: We analyzed images of the peripapillary areas in 10 healthy and 30 glaucomatous eyes (mild, moderate and advanced glaucoma, 10 eyes each), scanned with the Spectralis OCT (Heidelberg Engineering GmbH, Dossenheim, Germany). To calculate the RNFL attenuation coefficient (µatt), determined by the scattering properties of the RNFL, we used a model that normalized the reflectivity of the RNFL by the retinal pigment epithelium. The analysis was performed at 4 preset locations at ...

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    15. Classification Algorithms Enhance the Discrimination of Glaucoma from Normal eyes in High Definition Optical Coherence Tomography

      Classification Algorithms Enhance the Discrimination of Glaucoma from Normal eyes in High Definition Optical Coherence Tomography

      Purpose: To evaluate the diagnostic performance of classification algorithms based on Linear Discriminant Analysis (LDA) and Classification And Regression Tree (CART) methods, compared to optic nerve head (ONH) and retinal nerve fiber layer (RNFL) parameters measured by high-definition optical coherence tomography (Cirrus HD-OCT Version 4.5.1.1, Carl Zeiss Meditec Inc., CA) for discriminating glaucoma subjects. Methods: Consecutive glaucoma subjects (Training data=184; Validation data=102) were recruited from an eye center and normal subjects (n=508) from an ongoing Singaporean Chinese population based study. ONH and RNFL parameters were measured using Optic Disc Cube 200x200 scan protocol. LDA ...

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    16. Repeatability and reproducibility of manual choroidal volume measurements using enhanced depth imaging optical coherence tomography

      Repeatability and reproducibility of manual choroidal volume measurements using enhanced depth imaging optical coherence tomography

      Purpose: To evaluate the repeatability and reproducibility of manual choroidal volume (CV) measurements on spectral-domain optical coherence tomography (SD-OCT) using enhanced depth imaging (EDI). Methods: Sixty eyes of 32 patients with or without any ocular chorio-retinal diseases were enrolled prospectively. Thirty-one choroidal scans were performed on each eye centered at the fovea using a raster protocol. Two masked observers demarcated choroidal boundaries using the built-in automated retinal segmentation software on two separate sessions. The observers were masked to each other's and their own previous readings. A standardized grid centered on the fovea was positioned automatically by the Spectralis OCT ...

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    17. Theoretical, Experimental and Optical Coherence Tomography Studies of Graft Apposition and Adhesion in Descemets Stripping Endothelial Keratoplasty

      Theoretical, Experimental and Optical Coherence Tomography Studies of Graft Apposition and Adhesion in Descemets Stripping Endothelial Keratoplasty

      Purpose To investigate the effects of adhesion promoting surgical adjuncts in Descemets stripping automated endothelial kertaoplasty (DSAEK). The effects of air-fill pressure, duration, use of venting incisions and stromal roughening on fluid dispersion and donor adhesion strength were examined in theoretical, optical coherence tomography (OCT) and strain gauge models of DSAEK. Methods OCT analysis: DSAEK modeled using a microkeratome prepared lenticule inserted under a 'recipient' corneo-scleral rim mounted on an artificial anterior chamber. Pressure of 18mmHg (n=6) or 60mmHg (n=6) was applied. The area of interface fluid was measured sequentially. The area of interface fluid before and after ...

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    18. Reliability and reproducibility of assessment of corneal epithelial thickness by Fourier domain optical coherence tomography

      Reliability and reproducibility of assessment of corneal epithelial thickness by Fourier domain optical coherence tomography

      Purpose: To analyze the intra-user reliability and inter-user reproducibility of assessment of corneal epithelial thickness by Fourier domain optical coherence tomography. Method: In this consecutive cross sectional case series performed at a tertiary ocular care institution 210 eyes of 210 subjects underwent anterior segment Fourier domain optical coherence tomography (FDOCT) with Cirrus HD-OCT. 'Caliper tool' was used to measure the corneal thickness. For reproducibility measures, the examination was done by two examiners (user 1, user 2) within 30 minutes of each other. For reliability measure, the re-test was done by user 1 on the next day, within 30 minutes of ...

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    19. Glaucoma Diagnostic Ability of Quadrant and Clock-Hour Neuroretinal Rim Assessment Using Cirrus HD Optical Coherence Tomography

      Glaucoma Diagnostic Ability of Quadrant and Clock-Hour Neuroretinal Rim Assessment Using Cirrus HD Optical Coherence Tomography

      Purpose: To investigate the glaucoma diagnostic ability of quadrant and clock-hour neuroretinal rim assessment by Cirrus HD spectral-domain optical coherence tomography (OCT). Methods: Eighty eyes of 80 glaucoma patients and eighty eyes of 80 healthy subjects were enrolled. Peripapillary retinal nerve fiber layer (RNFL) thickness was measured by Cirrus HD-OCT. Quadrant and clock-hour rim areas and thicknesses were obtained from optic nerve head images and 360o circumferential rim thickness curve of Cirrus HD-OCT, respectively. Area under receiver operating characteristic curves (AUCs) and sensitivities of RNFL thicknesses, rim areas, and rim thicknesses at a 90% specificity level were calculated. Results: Quadrant ...

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    20. Influence of Clinically Invisible, but Optical Coherence Tomography Detected, Optic Disc Margin Anatomy on Neuroretinal Rim Evaluation

      Influence of Clinically Invisible, but Optical Coherence Tomography Detected, Optic Disc Margin Anatomy on Neuroretinal Rim Evaluation

      Purpose: We previously demonstrated that most eyes have regionally variable extensions of Bruch's membrane (BM) inside the clinically identified disc margin (DM) that are clinically and photographically invisible. We studied the impact of these findings on DM and BM opening (BMO) derived neuroretinal rim parameters. Methods: Disc stereo-photography and spectral domain optical coherence tomography (SD-OCT, 24 radial B-scans centred on the optic nerve head) were performed on 30 glaucoma patients and 10 age-matched controls. Photographs were co-localized to SD-OCT data such that the DM and BMO could be visualized in each B-scan. Three parameters were computed: (1) DM-horizontal rim ...

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    21. Image inversion spectral-domain optical coherence tomography optimizes choroidal thickness and detail through improved contrast

      Image inversion spectral-domain optical coherence tomography optimizes choroidal thickness and detail through improved contrast

      Purpose: To determine whether there were significant differences in choroidal thickness, contrast, outer choroidal vessel (OCV) and choroidal-scleral junction (CSJ) visualization in inverted versus upright spectral-domain optical coherence tomography (SD-OCT). Methods: Images were captured on Bioptigen SD-OCT (Bioptigen Inc., Research Triangle Park, North Carolina), Zeiss Cirrus HD-OCT (Carl Zeiss Meditec Inc, Dublin, CA), and Heidelberg Spectralis (Heidelberg Engineering, Heidelberg, Germany) in 42 eyes of 21 healthy subjects. Average choroidal thickness across a fovea-centered 4 mm segment was determined with MATLAB. Quantitative measures of choroidal contrast were measured and CSJ assessed by applying a 0-3 score. OCV was determined by counting ...

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    22. Analysis of Progression of Reticular Pseudodrusen by Spectral Domain–Optical Coherence Tomography

      Analysis of Progression of Reticular Pseudodrusen by Spectral Domain–Optical Coherence Tomography

      Purpose. To analyze reticular pseudodrusen progression using spectral domain–optical coherence tomography (SD-OCT). Methods. Thirty-three consecutive patients (48 eyes) underwent SD-OCT using the eye-tracked follow-up protocol 24 ± 2 months after baseline examination. Each pair of B-scans (only one per eye was evaluated among those showing pseudodrusen progression) was compared with respect to pseudodrusen appearance and retinal layer structure. Stage 1 pseudodrusen was defined as granular material between the RPE and the inner segment/outer segment (IS/OS), stage 2 as mounds of material sufficient to alter the contour of the IS/OS, stage 3 as thicker material adopting a conical ...

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    23. The Physiological Variation of the Retinal Nerve Fiber Layer Thickness and Macular Volume in Humans as Assessed by Spectral Domain–Optical Coherence Tomography

      The Physiological Variation of the Retinal Nerve Fiber Layer Thickness and Macular Volume in Humans as Assessed by Spectral Domain–Optical Coherence Tomography

      Purpose. With the introduction of spectral domain–optical coherence tomography (SD-OCT), changes in retinal nerve fiber layer (RNFL) thickness and macular volume (MV) can be detected with high precision. The aim of this study was to determine whether there is a physiological quantifiable degree of variation of these structures in humans. Methods. This study took place during a 10-km charity run at VU University Medical Center Amsterdam. Weight, height, hydration status, RNFL thickness (ring scan, 12° around the optic nerve head), and MV (20° × 20°) were assessed in 69 subjects (44 runners, 25 controls) using SD-OCT with eye-tracking function. The ...

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    24. Transsynaptic Retinal Degeneration in Optic Neuropathies: Optical Coherence Tomography Study

      Transsynaptic Retinal Degeneration in Optic Neuropathies: Optical Coherence Tomography Study

      Purpose. Recently demonstrated neuronal loss in the inner nuclear layer of the retina in multiple sclerosis (MS) and glaucoma raises the question of a primary (possibly immune-mediated) or secondary (transsynaptic) mechanism of retinal damage in these diseases. In the present study we used optical coherence tomography to investigate retrograde retinal transsynaptic degeneration in patients with long-standing and severe loss of ganglion cells due to optic neuropathy. Methods. Fifteen eyes of glaucoma patients with visual field defect limited to upper hemifield and 15 eyes of MS patients with previous episode of optic neuritis (ON) and extensive loss of ganglion cells were ...

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