1. Articles from Frank D. Verbraak

    1-15 of 15
    1. Subretinal Fibrosis Detection Using Polarization Sensitive Optical Coherence Tomography

      Subretinal Fibrosis Detection Using Polarization Sensitive Optical Coherence Tomography

      Purpose : Subretinal fibrosis (SRFib) is an important cause of permanent loss-of-vision diseases with submacular neovascularization, but a reliable diagnostic method is currently missing. This study uses polarization-sensitive optical coherence tomography (PS-OCT) to detect SRFib within retinal lesions by measurement of its birefringent collagen fibers. Methods : Twenty-five patients were enrolled with retinal pathology in one or both eyes containing (1) suspected SRFib, (2) lesions suspected not to be fibrotic, or (3) lesions with doubtful presence of SRFib. All eyes were evaluated for SRFIb using conventional diagnostics by three retinal specialists. PS-OCT images were visually evaluated for SRFib based on cumulative phase ...

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    2. Optical coherence tomography shows neuroretinal thinning in myelopathy of adrenoleukodystrophy

      Optical coherence tomography shows neuroretinal thinning in myelopathy of adrenoleukodystrophy

      Background Progressive myelopathy is the main cause of disability in adrenoleukodystrophy (ALD). Development of therapies is hampered by a lack of quantitative outcome measures. In this study, we investigated whether myelopathy in ALD is associated with retinal neurodegeneration on optical coherence tomography (OCT), which could serve as a surrogate outcome measure. Methods Sixty-two patients (29 men and 33 women) and 70 age-matched and sex-matched controls (33 men and 37 women) were included in this cross-sectional study. We compared retinal nerve fiber layer (RNFL), ganglion cell layer (GCL) and peripapillary retinal nerve fiber layer (pRNFL) thickness between ALD patients and controls ...

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    3. Optical coherence tomography (OCT) to image active and inactive retinoblastomas as well as retinomas

      Optical coherence tomography (OCT) to image active and inactive retinoblastomas as well as retinomas

      Purpose To illustrate Optical Coherence Tomography (OCT) images of active and inactive retinoblastoma (Rb) tumours. Methods Current observational study included patients diagnosed with retinoblastoma and retinoma who were presented at Amsterdam UMC and Jules‐Gonin Eye Hospital, between November 2010 and October 2017. Patients aged between 0 and 4 years were imaged under general anaesthesia with handheld OCT in supine position. Patients older than 4 years were imaged with the conventional OCT (Heidelberg Engineering, Heidelberg Spectralis, Germany). All patients included were divided into two groups: active and inactive tumours (retinoma and regression patterns). Patients’ medical records and OCT images were ...

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    4. Optic axis uniformity as a metric to improve the contrast of birefringent structures and analyze the retinal nerve fiber layer in polarization-sensitive optical coherence tomography

      Optic axis uniformity as a metric to improve the contrast of birefringent structures and analyze the retinal nerve fiber layer in polarization-sensitive optical coherence tomography

      A new metric is used to improve the contrast of birefringent structures in biological tissue using polarization-sensitive optical coherence tomography. This metric, optic axis uniformity (OAxU), is based on the optic axis of birefringence and quantifies the uniformity of the optic axis direction. OAxU provides surprisingly strong contrast for fibrous structures such as muscle and the retinal nerve fiber layer (RNFL). We used OAxU for automatic segmentation of the RNFL in human eyes. From the segmentation, en face images of RNFL thickness and RNFL birefringence were created. The measured birefringence values are consistent with earlier reports.

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    5. Optical density filters modeling media opacities cause decreased SD-OCT retinal layer thickness measurements with inter- and intra-individual variation

      Optical density filters modeling media opacities cause decreased SD-OCT retinal layer thickness measurements with inter- and intra-individual variation

      Purpose To assess the effect of media opacities on thickness measurements of the peripapillary retinal nerve fibre layer (pRNFL) and macular inner retinal layer (mIRL) performed with spectral-domain optical coherence tomography (SD-OCT) using a set of filters with known optical density. Methods Spectral-domain optical coherence tomography volume scans of the optic disc and the macular area were performed in 18 healthy volunteers, using Topcon-3DOCT-1000 Mark II. A set of five filters with optical density ranging from 0.04 to 0.69 was used. The correlation was calculated between the percentage change in thickness measurements (%ΔpRNFL and %ΔmIRL) and the change ...

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    6. Standardised disturbance of the optical coherence tomography signal has varying effects on the scan quality assessment when comparing four devices

      Standardised disturbance of the optical coherence tomography signal has varying effects on the scan quality assessment when comparing four devices

      Introduction Optical coherence tomography (OCT) has become a successful application in ophthalmology. Time-domain OCT (Stratus, Carl Zeiss Meditec) has been overtaken by spectral-domain OCT (SDOCT) which has major advances in imaging speed, sensitivity and image resolution. 1 , 2 Several SDOCT devices are commercially available. In this small study, we assessed the change in subjective image quality and image quality parameter (IQP) provided by four different SDOCT devices using artificial filters simulating optical eye media disturbances. Methods In four healthy subjects, single non-averaged B-scans of the macula were acquired using four commercially available SDOCT systems: 3D OCT-1000 MarkII (Topcon Medical Systems ...

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    7. Effect of Age on Individual Retinal Layer Thickness in Normal Eyes as Measured with Spectral-Domain Optical Coherence Tomography

      Effect of Age on Individual Retinal Layer Thickness in Normal Eyes as Measured with Spectral-Domain Optical Coherence Tomography

      Purpose. To determine the effect of age on the thickness of individual retinal layers, measured with spectral-domain optical coherence tomography (SD-OCT), in a population of healthy Caucasians. Methods. One hundred and twenty subjects with an age ranging between 18 and 81 years were examined with SD-OCT (Topcon, Mark II). Mean layer thickness was calculated for 7 retinal layers, in the fovea (region 1 of the 9 ETDRS regions), in the pericentral ring (ETDRS regions 2 to 5), and the peripheral ring (ETDRS region 6 to 9) following automated segmentation using the Iowa Reference Algorithm. In addition, mean peripapillary retinal nerve ...

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    8. The relationship between the optical density of cataract and its influence on retinal nerve fibre layer thickness measured with spectral domain optical coherence tomography

      The relationship between the optical density of cataract and its influence on retinal nerve fibre layer thickness measured with spectral domain optical coherence tomography

      Purpose:  The purpose of this study was to model the influence of cataract on Spectral Domain Optical Coherence Tomography (SDOCT) image quality and Retinal Nerve Fibre Layer (RNFL) thickness measurements. Methods:  SDOCT images, made with two different devices (3DOCT-1000, Topcon and Cirrus HD-OCT), before and after cataract surgery were compared and judged against measurements from normal subjects using artificial filters simulating the effects of cataract. Optical density of the images was calculated based on a mathematical model described previously. Results:  In total, forty-eight eyes were included for pre- and postoperative cataract extraction measurements. OCT image quality significantly (p < 0.001 ...

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    9. Feature Of The Week 9/2/12: Academic Medical Center at The University of Amsterdam Investigates Comparison of RNFL Thickness Measurements by SD-OCT Systems Using a Phantom Eye Model

      Feature Of The Week 9/2/12: Academic Medical Center at The University of Amsterdam Investigates Comparison of RNFL Thickness Measurements by SD-OCT Systems Using a Phantom Eye Model

      We developed a multi-layered phantom eye model that distinguishes instrumental from biological variation, to quantify differences in retinal nerve fiber layer (RNFL) thickness measurements by various spectral-domain optical coherence tomography (SD-OCT) systems. The eye model comprised a glass lens, water as vitreous and silicone elastomer based layers mimicking the retina (top layer thickness = 49 µm). We tested 3 RTVue OptoVue, 3 Cirrus Zeiss, 3 3DOCT-1000 Topcon and 3 Spectralis Heidelberg SD-OCT systems. With each system the layered phantom eye model was measured 5 times. An average RNFL thickness and standard deviation were determined by the apparatus using a circular scan ...

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    10. Comparison of retinal nerve fiber layer thickness measurements by spectral-domain optical coherence tomography systems using a phantom eye model

      Comparison of retinal nerve fiber layer thickness measurements by spectral-domain optical coherence tomography systems using a phantom eye model

      To quantify differences in nerve fiber layer thickness measurements by various spectral-domain optical coherence tomography (SD-OCT) systems, we developed a phantom eye model. We tested twelve SD-OCT systems of four manufacturers. All systems combined overestimated the 49 µm thick phantom RNFL thickness on average by 18 µm. Within brands, thickness measurements differed statistically significant for one Topcon, one RTVue and one Cirrus. Between brands, thickness determined with RTVue and Topcon differed statistically significant from Cirrus and Spectralis. The maximum difference between mean thicknesses is 3.6 µm within brands and 7.7 µm between brands.

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    11. Heartbeat-induced axial motion artifacts in optical coherence tomography measurements of the retina

      Heartbeat-induced axial motion artifacts in optical coherence tomography measurements of the retina
      Purpose: To investigate the cause of axial eye motion artifacts that occur in optical coherence tomography (OCT) imaging of the retina. Understanding the cause of these motions can lead to improved OCT image quality and therefore better diagnosis. Methods: 27 measurements were done on 5 subjects. We collected spectral-domain OCT images at the macula over periods up to 30 seconds. We calculated the axial shift of every average A-scan with respect to the previous average A-scan by calculating the cross-correlation. The frequency spectrum of the calculated shifts versus time was determined. The heart rate was determined from blood pressure measurements ...
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    12. Overlay of conventional angiographic and en-face OCT images enhances their interpretation

      Overlay of conventional angiographic and en-face OCT images enhances their interpretation

      Background Combining characteristic morphological and functional information in one image increases pathophysiologic understanding as well as diagnostic accuracy in most clinical settings. En-face optical coherence tomography (OCT) provides a high resolution, transversal OCT image of the macular area combined with a confocal image of the same area (OCT C-scans). Creating an overlay image of a conventional angiographic image onto an OCT image, using the confocal part to facilitate transformation, combines structural and functional information of the retinal area of interest. This paper describes the construction of such overlay images and their aid in improving the interpretation of OCT C-scans. Methods ...

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    13. Thickness Measurements of Donor Posterior Disks After Descemet Stripping Endothelial Keratoplasty With Anterior Segment Optical Coherence Tomography

      Purpose: To evaluate donor posterior disk thickness measured with anterior segment optical coherence tomography after Descemet stripping endothelial keratoplasty. Methods: Fifteen patients (17 eyes) after Descemet stripping endothelial keratoplasty, using manually dissected donor posterior disks, were measured with the Visante anterior segment optical coherence tomography (Carl Zeiss Meditec Inc, Dublin, CA). Optical coherence tomography scans were made in a radial pattern, 45 degrees apart, starting in the horizontal axis. Thickness measurements of the donor posterior disks were taken centrally and at fixed radii toward the periphery and were correlated to postoperative change in spherical equivalent (SE), best-corrected visual acuity (BCVA ...

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    14. A Model for the Effect of Disturbances in the Optical Media on the OCT Image Quality

      PURPOSE. The loss of quality of Optical Coherence Tomography (OCT) images resulting from disturbances in the optical media has been modeled. METHODS. OCT measurements were performed in two healthy volunteers using the StratusOCT. Optical disturbances were approached in three ways simulated with filters. The studied effects were: light attenuation (absorptive and reflective filters), refractive aberrations (defocusing lenses) and light scattering/straylight (scattering filters). The same examiner scanned the subjects with the filters placed in front of the eye. The signal strength (SS) values of the scans were then collected. The strength of the filters were expressed in Optical Density, determined ...

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    15. Decreased optical coherence tomography-measured pericentral retinal thickness in patients with diabetes mellitus type 1 with minimal diabetic retinopathy

      Aim: A comparison of retinal thickness (RT) measurements with optical coherence tomography (OCT) in patients with type 1 diabetes mellitus (DM) and no or minimal diabetic retinopathy (DR) versus healthy controls. Methods: Fifty-three patients with type 1 DM with no or minimal DR underwent full ophthalmic examination, fundus photography and OCT. Mean RT measured by OCT was calculated for the central fovea, the fovea, the pericentral and the peripheral area of the macula, and compared to healthy controls. Results: Mean RT in the pericentral area was lower in patients with minimal DR (267 µm ± 20 µm; n = 23) compared to ...

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    1-15 of 15
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    1. (15 articles) Frank D. Verbraak
    2. (11 articles) Academic Medical Center at the University of Amsterdam
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    Overlay of conventional angiographic and en-face OCT images enhances their interpretation Heartbeat-induced axial motion artifacts in optical coherence tomography measurements of the retina Comparison of retinal nerve fiber layer thickness measurements by spectral-domain optical coherence tomography systems using a phantom eye model Feature Of The Week 9/2/12: Academic Medical Center at The University of Amsterdam Investigates Comparison of RNFL Thickness Measurements by SD-OCT Systems Using a Phantom Eye Model The relationship between the optical density of cataract and its influence on retinal nerve fibre layer thickness measured with spectral domain optical coherence tomography Effect of Age on Individual Retinal Layer Thickness in Normal Eyes as Measured with Spectral-Domain Optical Coherence Tomography Standardised disturbance of the optical coherence tomography signal has varying effects on the scan quality assessment when comparing four devices Evaluation of Age-related Skin Changes and Instrument Reliability Using Clinical Probe Measurements and Imaging Modalities HP-OCT™ wins Victorian AEEA award – nominated for Sir William Hudson award Postdoctoral Scholar in High Resolution Retinal Imaging at The Ohio State University Cone Photoreceptor Integrity assessed with Adaptive Optics Imaging after Laser-Pointer-Induced Retinal Injury Quantitative assessment of macular microvasculature and radial peripapillary capillary plexus in the fellow eyes of patients with retinal vein occlusion using OCT angiography