1. Articles from iovs.org

  2. 241-264 of 550 « 1 2 ... 8 9 10 11 12 13 14 ... 21 22 23 »
    1. 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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    2. 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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    3. 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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    4. 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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    5. 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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    6. 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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    7. 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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    8. 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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    9. 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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    10. 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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    11. 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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    12. 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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    13. 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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    14. 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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    15. In vivo Assessment of Thickness and Reflectivity in a Rat Outer Retinal Degeneration Model with Ultrahigh Resolution Optical Coherence Tomography

      In vivo Assessment of Thickness and Reflectivity in a Rat Outer Retinal Degeneration Model with Ultrahigh Resolution Optical Coherence Tomography

      Purpose: To provide in vivo quantitative assessment of sodium iodate-induced retinal damage in a rat model of outer retina degeneration using ultrahigh resolution optical coherence tomography (UHR-OCT). Methods: Outer retinal degeneration was induced in 4 female Long Evans rats via tail vein injection of sodium iodate (40 mg/kg). Changes in the thickness and optical reflectivity of individual retinal layers were extracted using a semi-automatic segmentation algorithm and were assessed in vivo at 6 hours, days 1, 3 and 7 and up to 3 months post-injection with UHR-OCT. H & E histology was used to confirm the morphological changes observed in ...

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    16. Imaging of the Iridocorneal Angle with the RTVue Spectral Domain Optical Coherence Tomography

      Imaging of the Iridocorneal Angle with the RTVue Spectral Domain Optical Coherence Tomography

      Purpose: To determine the ability of the RTVue spectral domain optical coherence tomography (SDOCT) to image the anterior chamber angle (ACA). Methods: Consecutive subjects prospectively underwent ophthalmic evaluation including gonioscopy by an ophthalmologist and anterior chamber imaging with SDOCT (Optovue, Fremont, CA), adapted with a corneal lens adapter (CAM-L module) and anterior segment OCT (ASOCT, Visante, Carl Zeiss Meditec, Dublin, CA), both performed by a technician. Two different ophthalmologists, masked to gonioscopy findings assessed visualization of the scleral spur (SS), Schwalbe's line (SL) and trabecular meshwork (TM) by the two modalities. The ability to detect a closed angle was ...

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    17. Precision of High Definition Spectral-Domain Optical Coherence Tomography for Measuring Central Corneal Thickness

      Precision of High Definition Spectral-Domain Optical Coherence Tomography for Measuring Central Corneal Thickness

      Purpose: To assess the reliability of central corneal thickness (CCT) measurements using Cirrus high-definition optical coherence tomography (HD-OCT) in healthy subjects and its accuracy compared with ultrasonic pachymetry. Methods: Seventy-seven consecutive subjects were recruited for evaluating repeatability, and agreement between two examiners. To analyze repeatability, one examiner measured 77 eyes four times in succession. To study agreement between two observers, a second independently-trained examiner obtained another CCT measurement. We also measured eyes in a subgroup of 20 patients using standard ultrasonic pachymetry. Within-subject standard deviation (Sw), coefficient of variation (CV), limits of agreement (LoA), and intraclass correlation coefficient (ICC) data ...

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    18. Repeatability and Reproducibility of Subfoveal Choroidal Thickness in Normal Eyes of Japanese Using Different SD-OCT Devices

      Repeatability and Reproducibility of Subfoveal Choroidal Thickness in Normal Eyes of Japanese Using Different SD-OCT Devices

      Purpose. To compare subfoveal choroidal thickness (SCT) measurements of three different commercially available spectral-domain optical coherence tomography instruments with healthy eyes of Japanese. Methods. A prospective, cross-sectional study was performed at a single institution. SCT of the right eye of 43 normal subjects was measured using three different SD-OCTs: Heidelberg Spectralis-OCT (Spectralis), Cirrus HD-OCT (Cirrus), and Topcon 3D OCT-1000 Mark II (Topcon). Two separate measurements were performed for the same eye with a maximum by a single examiner. SCT was defined as the distance from the posterior edge of the retinal pigment epithelium to the choroid/sclera junction. After manual ...

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    19. Effect of Spectrum Bias on the Diagnostic Accuracy of Spectral-Domain Optical Coherence Tomography in Glaucoma

      Effect of Spectrum Bias on the Diagnostic Accuracy of Spectral-Domain Optical Coherence Tomography in Glaucoma

      Purpose. To evaluate the influence of a control group on the diagnostic accuracy of spectral-domain optical coherence tomography (SD-OCT) in early glaucoma. Methods. In a diagnostic, case–control study, 119 eyes of 60 normal subjects with no findings suspicious for glaucoma (control cohort 1); 76 eyes of 41 subjects referred by general ophthalmologists as glaucoma suspects based on optic disc morphology, but found by glaucoma experts to be normal but with physiological variations in their optic nerves (control cohort 2); and 65 eyes of 46 early-glaucoma patients (cases) underwent imaging of the optic nerve head (ONH), retinal nerve fiber layer ...

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    20. Relationships among Multifocal Electroretinogram Amplitude, Visual Field Sensitivity, and SD-OCT Receptor Layer Thicknesses in Patients with Retinitis Pigmentosa

      Relationships among Multifocal Electroretinogram Amplitude, Visual Field Sensitivity, and SD-OCT Receptor Layer Thicknesses in Patients with Retinitis Pigmentosa

      Purpose. To compare local functional measures, the multifocal electroretinogram (mfERG) and visual field sensitivity, with a local structural measure, spectral domain (SD) optical coherence tomography (OCT), of receptor damage in patients with retinitis pigmentosa (RP). Methods. MfERGs, visual fields, and SD-OCT scans were obtained from 10 patients with RP, ranging in age from 23 to 59 years. Average amplitudes, average linear sensitivities, and average layer thicknesses were measured from within the central 3° and from three concentric annuli located between 3° and 8°, 8° and 15°, and 15° and 24°. A computer program aided manual segmentation and calculated OCT thickness ...

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    21. Spontaneous Ocular and Neurologic Deficits in Transgenic Mouse Models of Multiple Sclerosis and Noninvasive Investigative Modalities: A Review

      Spontaneous Ocular and Neurologic Deficits in Transgenic Mouse Models of Multiple Sclerosis and Noninvasive Investigative Modalities: A Review

      Multiple sclerosis (MS) is an autoimmune, inflammatory, neurodegenerative, demyelinating disease of the central nervous system, predominantly involving myelinated neurons of the brain, spinal cord, and optic nerve. Optic neuritis is frequently associated with MS and often precedes other neurologic deficits associated with MS. A large number of patients experience visual defects and have abnormalities concomitant with neurologic abnormalities. Transgenic mice manifesting spontaneous neurologic and ocular disease are unique models that have revolutionized the study of MS. Spontaneous experimental autoimmune encephalomyelitis (sEAE) presents with spontaneous onset of demyelination, without the need of an injectable immunogen. This review highlights the various models ...

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      Mentions: Richard K. Lee
    22. Optical Coherence Tomographic Reflectivity of Photoreceptors beneath Cystoid Spaces in Diabetic Macular Edema

      Optical Coherence Tomographic Reflectivity of Photoreceptors beneath Cystoid Spaces in Diabetic Macular Edema

      Purpose: To investigate the relationship between the cystoid spaces in the outer plexiform layer (OPL) and the characteristics of the photoreceptors beneath the cystoid spaces in patients with diabetic macular edema (DME). Methods: In this observational cross-sectional study, we retrospectively reviewed consecutive 123 eyes of 96 patients with clinically significant macular edema, and investigated the characteristics of the photoreceptors on optical coherence tomography (OCT) images represented by the external limiting membrane (ELM) and the junction between inner and outer segments (IS/OS), and their association with the overlying cystoid spaces. Results: The areas beneath the cystoid spaces in the OPL ...

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    23. Spectral-Domain Optical Coherence Tomography of β-zone Peripapillary Atrophy: Influence of Myopia and Glaucoma

      Spectral-Domain Optical Coherence Tomography of β-zone Peripapillary Atrophy: Influence of Myopia and Glaucoma

      Purpose: To investigate the influence of glaucoma and myopia on the cross-sectional configuration of β-zone peripapillary atrophy (PPA-β) using spectral-domain optical coherence tomography (SD-OCT). Methods: Among 100 eyes of 100 consecutive patients with POAG regardless of intraocular pressure level and 100 eyes of 100 normal subjects, cross-sectional B-scan images of PPA-β obtained with SD-OCT were evaluated. PPA bed configurations were classified and associated factors were studied with multivariate analysis. Results: In 147 eyes with PPA-β (84 POAG and 63 normal eyes; P = 0.0012), PPA bed were composed of straight (14 POAG and 27 normal eyes) or downward-curved (19 and ...

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