1. Articles in category: Ophthalmology

    577-600 of 7528 « 1 2 ... 22 23 24 25 26 27 28 ... 312 313 314 »
    1. Characterization of Abnormal Optic Nerve Head Morphology in Albinism Using Optical Coherence Tomography

      Characterization of Abnormal Optic Nerve Head Morphology in Albinism Using Optical Coherence Tomography

      Purpose : To characterize abnormalities in three-dimensional optic nerve head (ONH) morphology in people with albinism (PWA) using spectral-domain optical coherence tomography (SD-OCT) and to determine whether ONH abnormalities relate to other retinal and clinical abnormalities. Methods : Spectral-domain OCT was used to obtain three-dimensional images from 56 PWA and 60 age- and sex-matched control subjects. B-scans were corrected for nystagmus-associated motion artefacts. Disc, cup, and rim ONH dimensions and peripapillary retinal nerve fiber layer (ppRNFL) thickness were calculated using Copernicus and ImageJ software. Results : Median disc areas were similar in PWA (median = 1.65 mm 2 ) and controls (1.71 mm ...

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    2. Thickness of the Macula, Retinal Nerve Fiber Layer, and Ganglion Cell Layer in the Epiretinal Membrane: The Repeatability Study of Optical Coherence Tomography

      Thickness of the Macula, Retinal Nerve Fiber Layer, and Ganglion Cell Layer in the Epiretinal Membrane: The Repeatability Study of Optical Coherence Tomography

      Purpose : To analyze the repeatability of measurements of the thicknesses of the macula, retinal nerve fiber layer (RNFL), and ganglion cell inner plexiform layer (GCIPL) using spectral-domain optical coherence tomography (SD-OCT) in the epiretinal membrane (ERM). Methods : The prospective study analyzed patients who visited our retinal clinic from June 2013 to January 2014. An experienced examiner measured the thicknesses twice using macular cube 512 × 128 and optic disc cube 200 × 200 scans. The repeatability of the thicknesses of the macula, RNFL, and GCIPL were compared using the intraclass correlation coefficient (ICC) of two groups based on the central macular thickness ...

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    3. Visual Prognosis of Eyes Recovering From Macular Hole Surgery Through Automated Quantitative Analysis of Spectral-Domain Optical Coherence Tomography (SD-OCT) Scans

      Visual Prognosis of Eyes Recovering From Macular Hole Surgery Through Automated Quantitative Analysis of Spectral-Domain Optical Coherence Tomography (SD-OCT) Scans

      Purpose : To determine the value of topographic spectral-domain optical coherence tomography (SD-OCT) imaging features assessed after macular hole repair surgery in predicting visual acuity (VA) outcomes. Methods : An automated algorithm was developed to topographically outline and quantify area, extent, and location of defects in the ellipsoid zone (EZ) band and inner retina layers in SD-OCT scans. We analyzed the correlation of these values with VA in longitudinal observations from 35 patients who underwent successful macular hole surgery, in their first observation after surgery (within 2 months), and in a single observation within 6 to 12 months after surgery. Image features ...

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    4. In Vivo Foveal Development Using Optical Coherence Tomography

      In Vivo Foveal Development Using Optical Coherence Tomography

      Purpose : To characterize the time course of normal foveal development in vivo in term infants and young children using handheld spectral-domain optical coherence tomography (HH-SDOCT). Methods : We obtained 534 HH-SDOCT scans from 261 infants, children, and young adults with a mean age of 4.9 years (range, 0–27 years). Each retinal layer was manually segmented in ImageJ and correlated with gestational age (GA) and visual acuity (VA). The developmental trajectories of each retinal layer at the fovea, parafovea, and perifovea were calculated using fractional polynomial modeling. Results : The central macular thickness (CMT) increases logarithmically between birth and 48.6 ...

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    5. PREDICTING RESPONSE OF EXUDATIVE AGE-RELATED MACULAR DEGENERATION TO BEVACIZUMAB BASED ON SPECTRALIS OPTICAL COHERENCE TOMOGRAPHY

      PREDICTING RESPONSE OF EXUDATIVE AGE-RELATED MACULAR DEGENERATION TO BEVACIZUMAB BASED ON SPECTRALIS OPTICAL COHERENCE TOMOGRAPHY

      Purpose: To identify baseline optical coherence tomography factors in exudative age-related macular degeneration that predict response to bevacizumab injections. Methods: Patients underwent spectral domain optical coherence tomography at diagnosis and the width, height, area, and location of the subretinal fluid, intraretinal fluid, pigment epithelial detachment, and subretinal tissue were measured. The location and size of photoreceptor and the loss of retinal pigment epithelium were recorded as well as quantitative retinal measurements. Patients received three consecutive monthly injections of bevacizumab after which their best-corrected visual acuity was recorded. Results: Overall 105 eyes of 105 patients aging 88 +/- 8.6 years were ...

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    6. Papilledema Outcomes from the Optical Coherence Tomography Substudy of the Idiopathic Intracranial Hypertension Treatment Trial

      Papilledema Outcomes from the Optical Coherence Tomography Substudy of the Idiopathic Intracranial Hypertension Treatment Trial

      Purpose To assess treatment efficacy using spectral-domain (SD) optical coherence tomography (OCT) measurements of papilledema in the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT), which evaluated the effects of acetazolamide and weight management and of placebo and weight management in eyes with mild visual loss. Design Randomized double-masked control clinical trial of acetazolamide plus weight management compared with placebo plus weight management in subjects with mild visual field loss and previously untreated idiopathic intracranial hypertension (IIH). Participants Eighty-nine (43 acetazolamide treated, 46 placebo treated) of 165 subjects meeting IIHTT entry criteria. Methods Subjects underwent perimetry, papilledema grading (Frisén method), high- ...

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    7. Reproducibility and Agreement Between 2 Spectral Domain Optical Coherence Tomography Devices for Anterior Chamber Angle Measurements

      Reproducibility and Agreement Between 2 Spectral Domain Optical Coherence Tomography Devices for Anterior Chamber Angle Measurements

      Purpose: To compare anterior chamber angle parameters based on the location of Schwalbe line (SL) from 2 spectral domain optical coherence tomography (SD-OCT) instruments and to measure their reproducibility. Methods: Forty-two eyes from 21 normal, healthy participants underwent imaging of the inferior irido-corneal angle with the Spectralis and Cirrus SD-OCT under tightly controlled low-light conditions. SL-angle opening distance (SL-AOD) and SL-trabecular iris space area (SL-TISA) were measured by masked, certified graders at the Doheny Imaging Reading Center using customized grading software. Interinstrument and intrainstrument, as well as interobserver and intraobserver reproducibility of SL-AOD and SL-TISA measurements were evaluated by intraclass ...

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    8. En face mode of swept-source optical coherence tomography in circumscribed choroidal haemangioma

      En face mode of swept-source optical coherence tomography in circumscribed choroidal haemangioma

      Purpose To describe the findings in circumscribed choroidal haemangioma (CCH) using en face swept-source optical coherence tomography (SS-OCT). Methods En face images were obtained employing DRI-1 Atlantis OCT (Topcon, Tokyo, Japan), using a three-dimensional volumetric scan of 12×9 mm. Images were obtained from the retinal pigment epithelium to 1000 μm in depth of the tumour. Results Twenty-two eyes from 22 patients with the clinical diagnosis of CCH were included. In 20 eyes (90.9%), a characteristic pattern was visualised in the en face image across the vascular tumour. A multilobular pattern, similar to a honeycomb, with hyporeflective, confluent, oval ...

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    9. Prediction of spontaneous closure of traumatic macular hole with spectral domain optical coherence tomography

      Prediction of spontaneous closure of traumatic macular hole with spectral domain optical coherence tomography

      It has been known that some traumatic macular holes can close spontaneously. However, knowledge about the types of macular hole that can close spontaneously is limited. In this retrospective study, we investigated patients with traumatic macular hole who were followed-up for at least 6 months without any surgical intervention. Clinical data and spectral domain optical coherence tomography (SD-OCT) images were compared between groups with and without macular hole closure. Overall, 27 eyes were included. Spontaneous closure of macular hole was observed in 10 (37.0%) eyes. The holes with spontaneous closure had smaller minimum diameter (244.9 ± 114.4 vs ...

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    10. Noninvasive vascular imaging of ruptured retinal arterial macroaneurysms by Doppler optical coherence tomography

      Noninvasive vascular imaging of ruptured retinal arterial macroaneurysms by Doppler optical coherence tomography

      Background To describe Doppler optical coherence tomography (OCT) imaging of ruptured retinal arterial macroaneurysms (RAMs). Methods Four eyes of four patients with ruptured RAMs were prospectively studied. Vascular imaging was obtained using swept-source Doppler OCT, and compared with indocyanine green angiography images. Results En face projection of Doppler OCT images clearly showed RAMs at the corresponding locations of lesions in the indocyanine green angiography images. In Doppler OCT images, RAMs were located in the inner retina in three eyes and in the medium layer of the retina in one eye. In one eye, detection of RAMs by standard OCT was ...

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    11. Volumetric ellipsoid zone mapping for enhanced visualisation of outer retinal integrity with optical coherence tomography

      Volumetric ellipsoid zone mapping for enhanced visualisation of outer retinal integrity with optical coherence tomography

      Objective assessment of retinal layer integrity with optical coherence tomography (OCT) is currently limited. The ellipsoid zone (EZ) has been identified as an important feature on OCT that has critical prognostic value in macular disorders. In this report, we describe a novel assessment tool for EZ integrity that provides visual and quantitative assessment across an OCT data set. Using this algorithm, we describe the findings in multiple clinical examples, including normal controls, age-related macular degeneration, drug effects (eg, ocriplasmin, hydroxychloroquine) and effects of surgical manipulation (eg, following membrane peeling using intraoperative OCT). EZ mapping provides both en face visualisation of ...

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    12. Retinal complications associated with congenital optic disc anomalies determined by swept source optical coherence tomography

      Retinal complications associated with congenital optic disc anomalies determined by swept source optical coherence tomography

      Optical coherence tomography has evolved over the past 2 decades to be an important ancillary method to evaluate diseases of the anterior and posterior segments of the eye. The more recent development of swept-source optical coherence tomography (SS-OCT) with a wavelength-tunable laser centered at 1050 nm and deeper imaging depth of 2.6 mm has enabled clinicians to evaluate congenital optic disc anomalies including optic disc pits, optic disc colobomas, and morning glory syndrome in more detail. The SS-OCT findings of the posterior precortical vitreous pocket, Cloquet's canal, lamina cribrosa that is torn from the peripapillary sclera, and the ...

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    13. Retinal pathology in idiopathic moyamoya angiopathy detected by optical coherence tomography

      Retinal pathology in idiopathic moyamoya angiopathy detected by optical coherence tomography

      Objective: To investigate whether patients with moyamoya angiopathy without obvious retinal pathologies such as retinal infarctions or the congenital morning glory anomaly may have subtle subclinical retinal changes. Methods: In this cross-sectional study, spectral domain optical coherence tomography was used to analyze the retinal morphology of 25 patients with idiopathic moyamoya angiopathy and 25 age- and sex-matched healthy controls. We analyzed the retinal vasculature with blue laser autofluorescence, lipofuscin deposits with MultiColor confocal scanning laser ophthalmoscopy, and the optic nerve head (ONH) volume with a custom postprocessing algorithm. In addition to the total retinal thickness, semiautomated segmentation was used for ...

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      Mentions: Friedemann Paul
    14. Wideband Electrically Pumped 1050-nm MEMS-Tunable VCSEL for Ophthalmic Imaging

      Wideband Electrically Pumped 1050-nm MEMS-Tunable VCSEL for Ophthalmic Imaging

      In this paper, we present a 1050-nm electrically pumped microelectromechanically tunable vertical cavity surface emitting laser (MEMS-VCSEL) with a record dynamic tuning bandwidth of 63.8 nm, suitable for swept-source optical coherence tomography (SS-OCT) imaging. These devices provide reduced cost and complexity relative to previously demonstrated optically pumped devices by obviating the need for a pump laser and associated hardware. We demonstrate ophthalmic SS-OCT imaging with the electrically-pumped MEMS-VCSEL at a 400 kHz axial scan rate for wide-field imaging of the in vivo human retina over a 12 mm × 12 mm field and for OCT angiography of the macula over ...

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    15. Depth Compensated Spectral Domain Optical Coherence Tomography via Digital Compensation

      Depth Compensated Spectral Domain Optical Coherence Tomography via Digital Compensation

      Spectral Domain Optical Coherence Tomography (SD-OCT) is a well-known imaging modality which allows for \textit{in-vivo} visualization of the morphology of different biological tissues at cellular level resolutions. The overall SD-OCT imaging quality in terms of axial resolution and Signal-to-Noise Ratio (SNR) degrades with imaging depth, while the lateral resolution degrades with distance from the focal plane. This image quality degradation is due both to the design of the SD-OCT imaging system and the optical properties of the imaged object. Here, we present a novel Depth Compensated SD-OCT (DC-OCT) system that integrates a Depth Compensating Digital Signal Processing (DC-DSP) module ...

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    16. Comparison of swept source optical coherence tomography (SS-OCT) and spectral domain optical coherence tomography (SD-OCT) in polypoidal choroidal vasculopathy

      Comparison of swept source optical coherence tomography (SS-OCT) and spectral domain optical coherence tomography (SD-OCT) in polypoidal choroidal vasculopathy

      Background Swept source optical coherence tomography (SS-OCT, Topcon Medical System, Japan) is known to have longer wavelength than spectral domain OCT (SD-OCT, Spectralis, Heidelberg Engineering, Germany), allowing a deeper penetration into retina and choroidal layers. This objective of this study was to compare the visibility of retinal and choroidal features in polypoidal choroidal vasculopathy (PCV) using SS-OCT and SD-OCT. Design Prospective comparative observational case series in Singapore National Eye Center (SNEC) Participants There were 20 eyes (20 patients) with PCV confirmed with indocyanine green angiogram (ICGA). Methods Six pre-specified OCT parameters (presence of polyps, sharp pigment epithelial detachment (PED) peak ...

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    17. Evaluation of the effect of elevated intraocular pressure and reduced ocular perfusion pressure on retinal capillary bed filling and total retinal blood flow in rats by OMAG/OCT

      Evaluation of the effect of elevated intraocular pressure and reduced ocular perfusion pressure on retinal capillary bed filling and total retinal blood flow in rats by OMAG/OCT

      Purpose To determine if retinal capillary filling is preserved in the face of acutely elevated intraocular pressure (IOP) in anesthetized rats, despite a reduction in total retinal blood flow (RBF), using optical microangiography/optical coherence tomography (OMAG/OCT). Methods OMAG provided the capability of depth-resolved imaging of the retinal microvasculature down to the capillary level. Doppler OCT was applied to measure the total RBF using an enface integration approach. The microvascular pattern, capillary density, and total RBF were monitored in vivo as the IOP was increased from 10 to 100 mm Hg in 10 mm Hg intervals and returned back ...

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    18. Comparison of Corneal Epithelial Thickness Measurement Between Fourier-Domain OCT and Very High-Frequency Digital Ultrasound

      Comparison of Corneal Epithelial Thickness Measurement Between Fourier-Domain OCT and Very High-Frequency Digital Ultrasound

      To compare measurements of corneal epithelial thickness using optical coherence tomography (OCT) and very high-frequency digital ultrasound (VHFDU). METHODS: Retrospective analysis of 189 virgin corneas and 175 post-laser refractive surgery (LRS) corneas that had corneal epithelial thickness measurement with RTVue Fourier-domain OCT (Optovue, Inc., Fremont, CA) (tear film included) and Artemis VHFDU (ArcScan Inc., Morrison, CO) (tear film excluded). Averages were calculated for the central 2-mm diameter zone and for two further concentric annuli of 1.5- and 0.5-mm width, each divided into eight sectors. Agreement was analyzed by mean difference (OCT – VHFDU), 95% limits of agreement (LoA) (1 ...

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    19. New ophthalmologic imaging techniques for detection and monitoring of neurodegenerative changes in diabetes: a systematic review

      New ophthalmologic imaging techniques for detection and monitoring of neurodegenerative changes in diabetes: a systematic review

      Optical coherence tomography (OCT) of the retina and around the optic nerve head and corneal confocal microscopy (CCM) are non-invasive and repeatable techniques that can quantify ocular neurodegenerative changes in individuals with diabetes. We systematically reviewed studies of ocular neurodegenerative changes in adults with type 1 or type 2 diabetes and noted changes in the retina, the optic nerve head, and the cornea. Of the 30 studies that met our inclusion criteria, 14 used OCT and 16 used CCM to assess ocular neurodegenerative changes. Even in the absence of diabetic retinopathy, several layers in the retina and the mean retinal ...

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    20. Optical coherence tomography reflects brain atrophy in MS: A four year study

      Optical coherence tomography reflects brain atrophy in MS: A four year study

      Objective : To determine whether atrophy of specific retinal layers and brain substructures are associated over time, in order to further validate the utility of optical coherence tomography (OCT) as an indicator of neuronal tissue damage in patients with multiple sclerosis (MS). Methods : Cirrus high definition OCT (including automated macular segmentation) was performed in 107 MS patients biannually (median follow-up: 46-months). Three-tesla magnetic resonance imaging brain scans (including brain-substructure volumetrics) were performed annually. Individual-specific rates of change in retinal and brain measures (estimated with linear regression) were correlated, adjusting for age, sex, disease duration, and optic neuritis (ON) history. Results : Rates ...

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    21. Estimating the Lead Time Gained by Optical Coherence Tomography in Detecting Glaucoma before Development of Visual Field Defects

      Estimating the Lead Time Gained by Optical Coherence Tomography in Detecting Glaucoma before Development of Visual Field Defects

      Purpose To estimate the diagnostic accuracy and lead time gained by retinal nerve fiber layer (RNFL) thickness measurements from optical coherence tomography (OCT) for detecting glaucoma before the development of visual field defects. Design Observational cohort study. Participants The study group included 75 eyes of 75 patients suspected of having glaucoma. These eyes had normal standard automated perimetry (SAP) at baseline and demonstrated repeatable (3 consecutive) abnormal tests during a median follow-up of 6.3 years. A control group of 75 eyes of 75 healthy subjects matched by age and number of OCT tests during follow-up was included. Methods The ...

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    22. Method And Apparatus For Creating Ocular Surgical And Relaxing Incisions

      Method And Apparatus For Creating Ocular Surgical And Relaxing Incisions

      A scanning system for treating target tissue in a patient's eye includes an ultrafast laser source configured to deliver a laser beam comprising a plurality of laser pulses; an Optical Coherence Tomography (OCT) device configured to generate signals which may be used to create an image of the cornea and limbus of the eye of the patient; a scanner configured to focus and direct the laser beam in a pattern within the cornea or limbus to create incisions therein; and a controller operatively coupled to the laser source and scanner configured to control the scanner to adjust the position ...

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    23. Measuring oxygen saturation in retinal and choroidal circulations in rats using visible light optical coherence tomography angiography

      Measuring oxygen saturation in retinal and choroidal circulations in rats using visible light optical coherence tomography angiography

      Visible light optical coherence tomography (vis-OCT) has demonstrated its capability of measuring vascular oxygen saturation (sO 2 ) in vivo . Enhanced by OCT angiography, the signal from microvasculature can be further isolated and directly used for sO 2 extraction. In this work, we extended the theoretical formulation for OCT angiography-based oximetry by incorporating the contribution from motion contrast enhancement. We presented a new method to eliminate the associated confounding variables due to blood flow. First, we performed in vitro experiments to verify our theory, showing a stable spectral derivative within the selected wavelength bands for sO 2 extraction. Then, we tested ...

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    24. Comparison of the polarization properties in the retinas of different rodents using high resolution polarization sensitive OCT

      Comparison of the polarization properties in the retinas of different rodents using high resolution polarization sensitive OCT

      Animal models play an important role for understanding the pathophysiology of glaucoma and age-related macular degeneration. With these models, longitudinal studies can be performed and therefore there is need for non-invasive evaluation of disease progress. For that purpose optical coherence tomography (OCT) can be used. Since tissues with different polarization properties are important in these diseases, polarization sensitive OCT (PS-OCT) could be a valuable tool in preclinical research. In this work a high resolution PS-OCT (HR-PS-OCT) system was used in-vivo for rodent retinal imaging. A super luminescent diode with a bandwidth of 100 nm was used as a light source ...

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