1. Articles in category: Ophthalmology

    553-576 of 7064 « 1 2 ... 21 22 23 24 25 26 27 ... 293 294 295 »
    1. Retinal angiography with real-time speckle variance optical coherence tomography

      Retinal angiography with real-time speckle variance optical coherence tomography

      This report describes a novel, non-invasive and label-free optical imaging technique, speckle variance optical coherence tomography (svOCT), for visualising blood flow within human retinal capillary networks. This imaging system uses a custom-built swept source OCT system operating at a line rate of 100 kHz. Real-time processing and visualisation is implemented on a consumer grade graphics processing unit. To investigate the quality of microvascular detail acquired with this device we compared images of human capillary networks acquired with svOCT and fluorescein angiography. We found that the density of capillary microvasculature acquired with this svOCT device was visibly greater than fluorescein angiography ...

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    2. Posterior Vitreous Mobility Delineated by Tracking of Optical Coherence Tomography Images in Eyes with Idiopathic Macular Holes

      Posterior Vitreous Mobility Delineated by Tracking of Optical Coherence Tomography Images in Eyes with Idiopathic Macular Holes

      Purpose To demonstrate the posterior vitreous mobility following eye movements in patients forming macular holes, using an optical coherence tomography (OCT) eye tracking system. Design Prospective consecutive interventional case series. Methods Twenty four eyes of seventeen consecutive patients with idiopathic macular hole and the remaining fellow eyes were recruited. Following acquisition of baseline fundus scans, all patients were instructed to perform sets of standardized full excursion, vertical and horizontal eye movements. Immediately after each set of movements an OCT scan registered to the baseline fundus image was obtained using the eye tracking system. Three images were then overlaid using picture-editing ...

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    3. Retinal Ganglion Cell Layer Analysis by Optical Coherence Tomography in Toxic and Nutritional Optic Neuropathy

      Retinal Ganglion Cell Layer Analysis by Optical Coherence Tomography in Toxic and Nutritional Optic Neuropathy

      Objective: To analyze the retinal ganglion cell layer (RGL) by optical coherence tomography (OCT) in toxic and nutritional optic neuropathy and to correlate its thickness and volume with functional damage. Methods: We conducted an observational cross-sectional study in healthy subjects and in patients with toxic optic neuropathy observed in the Neuro-Ophthalmology Department of Central Lisbon Hospital Center. Complete ophthalmologic examination, OCT (Heidelberg Spectralis), and automated static perimetry were performed. Thickness and macular volume of RGL layer and inner plexiform layer were measured after manual segmentation. Results: The study included 16 eyes of 12 healthy subjects and 16 eyes of 8 ...

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    4. Assessing Age-Related Changes in the Biomechanical Properties of Rabbit Lens Using a Coaligned Ultrasound and Optical Coherence Elastography System

      Assessing Age-Related Changes in the Biomechanical Properties of Rabbit Lens Using a Coaligned Ultrasound and Optical Coherence Elastography System

      Purpose. To evaluate the capability of a novel, coaligned focused ultrasound and phase-sensitive optical coherence elastography (US-OCE) system to assess age-related changes in biomechanical properties of the crystalline lens in situ. Methods. Low-amplitude elastic deformations in young and mature rabbit lenses were measured by an US-OCE system consisting of a spectral-domain optical coherence tomography (OCT) system coaligned with a focused ultrasound system used to produce a transient force on the lens surface. Uniaxial compressional tests were used to validate the OCE data. Results. The OCE measurements showed that the maximum displacements of the young rabbit lenses were significantly larger than ...

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    5. En face swept-source optical coherence tomography in neovascular age-related macular degeneration

      En face swept-source optical coherence tomography in neovascular age-related macular degeneration

      Purpose To describe en face swept-source optical coherence tomography (SS-OCT) findings in the retinal pigment epithelium (RPE) and choroid and to correlate them with fluorescein angiography (FA) and/or indocyanine green angiography (ICGA) in neovascular age-related macular degeneration (AMD). Methods Thirty-eight eyes with the recent diagnosis of neovascular AMD were imaged using an SS-OCT system. En face images were obtained at RPE, choriocapillaris, Sattler's layer and Haller's layer level. Analysis of the images and correlation with colour fundus photographs, FA, ICGA in selected cases, were made. Results En face images at RPE level revealed changes in all eyes ...

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    6. En face optical coherence tomography of foveal microstructure in full-thickness macular hole: a model to study perifoveal Müller cells

      En face optical coherence tomography of foveal microstructure in full-thickness macular hole: a model to study perifoveal Müller cells

      Purpose To characterize perifoveal intraretinal cavities observed around full-thickness macular holes (MH) using en face optical coherence tomography and to establish correlations with histology of human and primate maculae. Design Retrospective non-consecutive observational case series. Methods Macular en face scans of eight patients with MH were analyzed to quantify the areas of hyporeflective spaces, and compared with macular flat-mounts and sections from one normal human donor eye and two normal primate eyes (Macaca fascicularis). Immunohistochemistry was used to study the distribution of glutamine synthetase, expressed by Müller cells, and zonula occludens-1, a tight-junction protein. Results The mean area of ...

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    7. Comparison of Optical Coherence Tomography Findings in Patients With Primary Open-angle Glaucoma and Parkinson Disease

      Comparison of Optical Coherence Tomography Findings in Patients With Primary Open-angle Glaucoma and Parkinson Disease

      Purpose: To evaluate the peripapillary retinal nerve fiber layer (RNFL), ganglion cell complex, and macular thickness as well as their correlation with the severity of diseases. Materials and Methods: This is a cross-sectional study and comparing both eyes of 26 patients with primary open-angle glaucoma, 25 patients with Parkinson disease (PD), and 23 healthy subjects. RNFL, ganglion cell complex, and macular thickness were measured and analyzed with optical coherence tomography (OCT) in all cases and correlation with severity of the disease was assessed in PD group. Results: The mean RNFL of PD was significantly thinner compared with controls (P=0 ...

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    8. Pattern of Macular Ganglion Cell-Inner Plexiform Layer Defect Generated by Spectral-Domain OCT in Glaucoma Patients and Normal Subjects

      Pattern of Macular Ganglion Cell-Inner Plexiform Layer Defect Generated by Spectral-Domain OCT in Glaucoma Patients and Normal Subjects

      Purpose: To elucidate patterns of macular ganglion cell-inner plexiform layer (GCIPL) defects by Cirrus optical coherence tomography (OCT) and examine the spatial relationship between GCIPL defect and visual field (VF) defect patterns. Methods: A total of 116 eyes of 116 normal subjects and 111 eyes of 111 glaucoma patients were included. The 227 study subjects underwent Cirrus OCT imaging in macular cube mode and reliable standard VF testing. Two ophthalmologists blindly classified GCIPL defect patterns and VF defects. The frequency distribution of GCIPL defect patterns and spatial relationships between GCIPL defects and VF defects were investigated. Results: GCIPL defect patterns ...

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    9. Optical Coherence Tomography versus Visual Evoked Potentials in detecting subclinical visual impairment in multiple sclerosis

      Optical Coherence Tomography versus Visual Evoked Potentials in detecting subclinical visual impairment in multiple sclerosis

      Rationale . Visual impairment is one of the most common clinical manifestations of multiple sclerosis (MS). Some multiple sclerosis patients complain of poor vision although the Snellen visual acuity is 20/20. This study reveals that sensitive measurements like visual evoked potential (VEP) and optical coherence tomography (OCT) can evidence subclinical disturbances of visual pathway. These methods examine the relation between the visual function (VEP) and retinal nerve fiber layer (RNFL) thickness, as a structural biomarker for axonal loss in patients with multiple sclerosis (MS). The findings in this study indicate the utility of combining structural and functional testing in clinical ...

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    10. NASA presents Heidelberg Engineering the NASA Certificate of Appreciation

      NASA presents Heidelberg Engineering the NASA Certificate of Appreciation

      Heidelberg Engineering was honored today by visitors from NASA. The guests from NASA: Dr. Christian Otto, Lead Scientist for the Vision Impairment and Intracranial Pressure (VIIP) project ; Dr. Steven Hart, lead flight surgeon for VIIP ; Rachel Brady, VIIP Science Coordinator; and Jennifer Villarreal, Project Manager came for a ceremony to present Heidelberg Engineering with the NASA Certificate of Appreciation in recognition of Heidelberg Engineering’s support in placing a SPECTRALIS ® OCT system on the International Space Station (ISS). During the ceremony, the NASA guests described the physiological challenges encountered with long duration space flight and the research underway to understand ...

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    11. Reproducibility of peripapillary retinal nerve fiber layer thickness measurements with cirrus HD-OCT in glaucomatous eyes

      Reproducibility of peripapillary retinal nerve fiber layer thickness measurements with cirrus HD-OCT in glaucomatous eyes

      AIM: To assess the reproducibility of Cirrus high-definition optical coherence tomography (HD-OCT; Carl Zeiss Meditec, Dublin, CA, USA) for analysis of peripapillary retinal nerve fiber layer (RNFL) thickness in glaucomatous eyes METHODS: Forty-five eyes (one eye from each glaucomatous patient) were imaged with Cirrus HD-OCT. Each eye was imaged three times by two separate operators. Intraclass correlation coefficient (ICC), coefficient of variation (CV), and test-retest variability were evaluated for both intraobserver and interobsever measurements RESULTS: In intraobserver measurements, the average RNFL thickness ICC was 0.983. CV and test-retest variability were 2.3% and 4.4 μm respectively. In quadrants ...

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    12. Quantitative Analysis of Microdistortions in Bowman’s Layer Using Optical Coherence Tomography After SMILE Among Different Myopic Corrections

      Quantitative Analysis of Microdistortions in Bowman’s Layer Using Optical Coherence Tomography After SMILE Among Different Myopic Corrections

      PURPOSE: To quantitatively analyze the characteristics of Bowman’s layer microdistortions after femtosecond laser small incision lenticule extraction (SMILE) among different myopic corrections, and their correlations with stromal lenticule thickness. . METHODS: In this nonrandomized, prospective, controlled study, 63 eyes of 32 consecutive patients undergoing SMILE were divided into three groups according to the preoperative spherical equivalent (SE): greater than −6.00 D (20 eyes), −3.00 to −6.00 D (26 eyes), and −3.00 D or less (17 eyes). Measurement by slit-lamp microscope, uncorrected distance visual acuity (UDVA), manifest refraction, and Fourier-domain optical coherence tomography (FD-OCT) were conducted preoperatively ...

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      Mentions: Fudan University
    13. Compare the effects of two silicone-hydrogel bandage contact lenses on epithelial healing after photorefractive keratectomy with anterior segment optical coherence tomography

      Compare the effects of two silicone-hydrogel bandage contact lenses on epithelial healing after photorefractive keratectomy with anterior segment optical coherence tomography

      Purpose To evaluate the efficacy of two silicone hydrogel bandage lenses (SiHy) on epithelial healing following photorefractive keratectomy (PRK) with anterior segment optical coherence tomography (AS-OCT). Methods Forty-two eyes of 21 patients who underwent PRK were included in a contralateral eye comparison study. At the end of the procedure, one eye of each patient was fitted with a Lotrafilcon B contact lens whereas the fellow eye was fitted with a Comfilicon A lens. Patients were examined on the day of surgery and at days 1–5 postoperatively. Main outcome measures were number of reepithelialized eyes, epithelial defect size, patient discomfort ...

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    14. Changes in choroidal thickness during pregnancy detected by enhanced depth imaging optical coherence tomography

      Changes in choroidal thickness during pregnancy detected by enhanced depth imaging optical coherence tomography

      Aim To compare the choroidal thickness measurements of healthy pregnant women obtained in the first trimester with measurements obtained in the third trimester using enhanced depth imaging optical coherence tomography (OCT). Methods 54 eyes of 27 healthy pregnant women and 50 eyes of 25 age matched healthy women were enrolled in this observational, cross-sectional study. The pregnant women underwent two OCT scans, one in the first trimester at gestational weeks 6–8, and the other during the third trimester at gestational weeks 32–37; the control group had OCT scanning during the follicular phase of the menstrual cycle, using the ...

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    15. Fourier-Domain Optical Coherence Tomography for Monitoring the Lower Tear Meniscus in Dry Eye after Acupuncture Treatment

      Fourier-Domain Optical Coherence Tomography for Monitoring the Lower Tear Meniscus in Dry Eye after Acupuncture Treatment

      Dry eye is highly prevalent and has a significant impact on quality of life. Acupuncture was found to be effective to treat dry eye. However, little was known about the effect of acupuncture on different subtypes of dry eye. The objective of this study was to investigate the applicability of tear meniscus assessment by Fourier-domain optical coherence tomography in the evaluation of acupuncture treatment response in dry eye patients and to explore the effect of acupuncture on different subtypes of dry eye compared with artificial tear treatment. A total of 108 dry eye patients were randomized into acupuncture or artificial ...

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      Mentions: Fudan University
    16. Whole Eye Segment Imaging and Measurement With Dual-Channel Spectral-Domain OCT

      Whole Eye Segment Imaging and Measurement With Dual-Channel Spectral-Domain OCT

      BACKGROUND AND OBJECTIVES: To image and measure whole eye segments using dual-channel spectral-domain optical coherence tomography (SD-OCT) and to compare the results with those from the IOLMaster (Carl Zeiss Meditec, Dublin, CA). PATIENTS AND METHODS: Twenty eyes of 20 volunteers were recruited. Ocular dimensions, including cornea thickness, anterior chamber depth (ACD), lens thickness, anterior lens surface curvature, and axial length (AL), were calculated. The reproducibility of SD-OCT measurements, statistical significance of inter-instrument difference, correlation, and agreement were evaluated. RESULTS: No significant differences were found between independent SD-OCT measurements ( P > .05). The ACD and AL measured with IOLMaster were significantly shorter ...

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    17. Comparison of Retinal Thicknesses Measured Using Swept-Source and Spectral-Domain Optical Coherence Tomography Devices

      Comparison of Retinal Thicknesses Measured Using Swept-Source and Spectral-Domain Optical Coherence Tomography Devices

      To compare retinal thicknesses measured using swept-source optical coherence tomography (SS-OCT) and spectral-domain (SD) OCT devices. PATIENTS AND METHODS: In a cohort study of 76 healthy eyes and 21 eyes with high myopia, mean retinal thicknesses in ETDRS subfields were compared between OCT scans obtained from the Topcon DRI OCT-1 (Topcon, Tokyo, Japan), Spectralis OCT (Heidelberg Engineering, Heidelberg, Germany), and Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA). RESULTS: Central retinal thickness measurements differed significantly among the three OCT devices (Spectralis: 271 µm; Cirrus: 254 µm; DRI OCT-1: 238 µm; P < .001), with mean differences ranging from 15.6 µm to ...

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    18. Imaging Areas of Retinal Nonperfusion in Ischemic Branch Retinal Vein Occlusion With Swept-Source OCT Microangiography

      Imaging Areas of Retinal Nonperfusion in Ischemic Branch Retinal Vein Occlusion With Swept-Source OCT Microangiography

      The authors present the case of a patient with a history of ischemic branch vein occlusion and multimodal imaging of the retinal vasculature by fluorescein angiography (FA) and ultrahigh-speed swept-source optical coherence tomography (SS-OCT) microangiography (SS-OCT laser prototype; 1,050 nm, 100,000 A-scans/second). Multiple images across the macula were acquired (3 × 3 mm cubes in clusters of four repeated B-scans). En face images of the vasculature were generated by implementing an intensity differentiation algorithm. The retinal vasculature as well areas of nonperfusion could be identified precisely at multiple retinal levels. Ultrahigh-speed SS-OCT microangiography provides noninvasive, three-dimensional, high-resolution images ...

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    19. Spectral-Domain Optical Coherence Tomography Features of Bilateral Chorioretinitis Sclopetaria

      Spectral-Domain Optical Coherence Tomography Features of Bilateral Chorioretinitis Sclopetaria

      The authors report a case of bilateral chorioretinitis sclopetaria in a 31-year-old man who sustained a perforating gunshot trauma. On presentation, best corrected visual acuity was light perception in the right eye and counting fingers at 5 feet in the left eye. Funduscopic examination demonstrated bilateral peripapillary fibrogliotic lesions with associated pigmentation in the posterior pole. Spectral-domain optical coherence tomography scans revealed bilateral full-thickness hyperreflectivity consistent with chorioretinal disruption. The patient was closely monitored, and his vision remained stable at 6-week follow-up.

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    20. Morphometry of the trabecular meshwork in vivo in a healthy population using Fourier domain optical coherence tomography

      Morphometry of the trabecular meshwork in vivo in a healthy population using Fourier domain optical coherence tomography

      Purpose: To measure the length, thickness and area of the trabecular meshwork (TM) in vivo using Fourier domain optical coherence tomography (FD-OCT) in a Caucasian population of healthy subjects. Methods: Cross-sectional study of 1,006 healthy subjects. Left eyes were randomly selected. Age, gender, intraocular pressure and spherical refractive error were noted down. The depth and volume of the anterior chamber and the central corneal thickness were measured with Pentacam®, while IOL Master® was used to measure the axial length. The length, thickness and area of the TM were measured through FD-OCT RTVue®. A study was carried out to determine ...

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    21. Spectral-Domain Optical Coherence Tomography Measurements of Choroidal Thickness and Outer Retinal Disruption in Macular Telangiectasia Type 2

      Spectral-Domain Optical Coherence Tomography Measurements of Choroidal Thickness and Outer Retinal Disruption in Macular Telangiectasia Type 2

      To evaluate subfoveal choroidal thickness (CT) and the extent of outer retinal disruption in patients with macular telangiectasia type 2 (MacTel2) compared with healthy eyes. PATIENTS AND METHODS: In this prospective, observational, cohort study, 62 patients (62 eyes) with Mac-Tel2 and 130 healthy controls (130 eyes) underwent a complete ophthalmological examination, spectral-domain optical coherence tomography (SD-OCT) imaging, and axial length measurements. Patients in the study group also underwent color fundus photography, fundus autofluorescence, and fluorescein angiography. En face SD-OCT imaging was used to assess abnormalities involving the photoreceptor inner segment/outer segment/ellipsoid zone (IS/OS/EZ). RESULTS: After adjusting ...

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