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Translational Vision Science & Technology

WanFen Yip, Yih Chung Tham, Wynne Hsu, Mong Li Lee, Ronald Klein, Barbara Klein, Mohammad Kamran Ikram, Tien Yin Wong, Carol Yim-Lui Cheung
PURPOSE: To compare three commonly used retinal vessel caliber measurement software systems, and propose an algorithm for conversion between measurement systems. METHODS: We used 120 retinal photographs to evaluate the agreement between three commonly used software (Retinal Analysis [RA], Integrative Vessel Analysis [IVAN], and Singapore I Vessel Assessment [SIVA]). Bland-Altman plots were used to evaluate agreement of retinal arteriolar (central retinal artery equivalent, CRAE) and venular (central retinal vein equivalent, CRVE) calibers...
October 2016: Translational Vision Science & Technology
Maria A Parker, Dongseok Choi, Laura R Erker, Mark E Pennesi, Paul Yang, Elvira N Chegarnov, Peter N Steinkamp, Catherine L Schlechter, Claire-Marie Dhaenens, Saddek Mohand-Said, Isabelle Audo, Jose Sahel, Richard G Weleber, David J Wilson
PURPOSE: The goal of this analysis was to determine the test-retest variability of functional and structural measures from a cohort of patients with advanced forms of Stargardt Disease (STGD) participating in the SAR422459 (NCT01367444) gene therapy clinical trial. METHODS: Twenty-two participants, aged 24 to 66, diagnosed with advanced forms of STGD, with at least one pathogenic ABCA4 mutation on each chromosome participating in the SAR422459 (NCT01367444) gene therapy clinical trial, were screened over three visits within 3 weeks or less...
October 2016: Translational Vision Science & Technology
Tetsu Asami, Hiroki Kaneko, Kensaku Miyake, Ichiro Ota, Goichiro Miyake, Seiichi Kato, Shunsuke Yasuda, Takeshi Iwase, Yasuki Ito, Hiroko Terasaki
PURPOSE: We report a newly developed device to fragment thrombi in retinal vein occlusion. METHODS: The new instrument consists of a 23-gauge (G) pipe and a 37-G needle with an internal wire. A total of 40 porcine eyes were used; 20 eyes for experiments in the branch retinal vein (BRV group) and 20 eyes for experiments in the central retinal vein (CRV group). We placed 25-G 3-port trocars, and core vitrectomy was performed. Another 23-G scleral incision was performed for insertion of the needle...
September 2016: Translational Vision Science & Technology
Peter B M Thomas, Tadas Baltrušaitis, Peter Robinson, Anthony J Vivian
PURPOSE: We validate a video-based method of head posture measurement. METHODS: The Cambridge Face Tracker uses neural networks (constrained local neural fields) to recognize facial features in video. The relative position of these facial features is used to calculate head posture. First, we assess the accuracy of this approach against videos in three research databases where each frame is tagged with a precisely measured head posture. Second, we compare our method to a commercially available mechanical device, the Cervical Range of Motion device: four subjects each adopted 43 distinct head postures that were measured using both methods...
September 2016: Translational Vision Science & Technology
Pedro Guimarães, Jeffrey Wigdahl, Alfredo Ruggeri
PURPOSE: We describe a novel fully automatic method capable of tracing the subbasal plexus nerves from human corneal confocal images. METHODS: Following an increasing interest in the automatic analysis of corneal nerves, a few approaches have been proposed. These, however, cannot cope with large images, such as mosaics, in due time. The rationale of the proposed method is to minimize required computing time while still providing accurate results. Our method consists of two sequential steps - a thresholding step followed by a supervised classification...
September 2016: Translational Vision Science & Technology
Danny Mitry, Kris Zutis, Baljean Dhillon, Tunde Peto, Shabina Hayat, Kay-Tee Khaw, James E Morgan, Wendy Moncur, Emanuele Trucco, Paul J Foster
PURPOSE: Crowdsourcing is based on outsourcing computationally intensive tasks to numerous individuals in the online community who have no formal training. Our aim was to develop a novel online tool designed to facilitate large-scale annotation of digital retinal images, and to assess the accuracy of crowdsource grading using this tool, comparing it to expert classification. METHODS: We used 100 retinal fundus photograph images with predetermined disease criteria selected by two experts from a large cohort study...
September 2016: Translational Vision Science & Technology
Alex R Bowers, Sarah S Sheldon, Dawn K DeCarlo, Eli Peli
PURPOSE: To investigate the telescope use and driving patterns of bioptic drivers with age-related macular degeneration (AMD). METHODS: A questionnaire addressing telescope use and driving patterns was administered by telephone interview to three groups of bioptic drivers: AMD (n = 31; median 76 years); non-AMD first licensed with a bioptic (n = 38; 53 years); and non-AMD first licensed without a bioptic (n = 47; 37 years). Driving patterns of bioptic AMD drivers were also compared with those of normal vision (NV) drivers (n = 36; 74 years) and nonbioptic AMD drivers (n = 34; 79 years)...
September 2016: Translational Vision Science & Technology
Sean McCafferty, Garrett Lim, William Duncan, Eniko Enikov, Jim Schwiegerling
PURPOSE: We evaluate solutions for an applanating surface modification to the Goldmann tonometer prism, which substantially negates the errors due to patient variability in biomechanics. METHODS: A modified Goldmann or correcting applanation tonometry surface (CATS) prism is presented which was optimized to minimize the intraocular pressure (IOP) error due to corneal thickness, stiffness, curvature, and tear film. Mathematical modeling with finite element analysis (FEA) and manometric IOP referenced cadaver eyes were used to optimize and validate the design...
September 2016: Translational Vision Science & Technology
Cheuk Wang Chung, Marcus Ang, Mohamed Farook, Nicholas G Strouthidis, Joddhbir S Mehta, Jean Martial Mari, Michaël J A Girard
PURPOSE: To establish and to rank the performance of a corneal adaptive compensation (CAC) algorithm in enhancing corneal images with scars acquired from three commercially available anterior segment optical coherence tomography (ASOCT) devices. METHODS: Horizontal B-scans of the cornea were acquired from 10 patients using three ASOCT devices (Spectralis, RTVue, and Cirrus). We compared ASOCT image quality (with and without CAC) by computing the intralayer contrast (a measure of shadow removal), the interlayer contrast (a measure of tissue boundary visibility), and the tissue/background contrast (a measure of overall corneal visibility)...
September 2016: Translational Vision Science & Technology
Candice Davidoff, Maureen Neitz, Jay Neitz
PURPOSE: The genetics underlying inherited color vision deficiencies is well understood: causative mutations change the copy number or sequence of the long (L), middle (M), or short (S) wavelength sensitive cone opsin genes. This study evaluated the potential of opsin gene analyses for use in clinical diagnosis of color vision defects. METHODS: We tested 1872 human subjects using direct sequencing of opsin genes and a novel genetic assay that characterizes single nucleotide polymorphisms (SNPs) using the MassArray system...
September 2016: Translational Vision Science & Technology
Luke X Chong, Andrew Turpin, Allison M McKendrick
PURPOSE: To validate the performance of a new perimetric algorithm (Gradient-Oriented Automated Natural Neighbor Approach; GOANNA) in humans using a novel combination of computer simulation and human testing, which we call Artificial Scotoma Generation (ASG). METHODS: Fifteen healthy observers were recruited. Baseline conventional automated perimetry was performed on the Octopus 900. Visual field sensitivity was measured using two different procedures: GOANNA and Zippy Estimation by Sequential Testing (ZEST)...
September 2016: Translational Vision Science & Technology
Joshua L Warren, Jean-Claude Mwanza, Angelo P Tanna, Donald L Budenz
PURPOSE: We developed a statistical model to improve the detection of glaucomatous visual field (VF) progression as defined by the consensus of expert clinicians. METHODS: We developed new methodology in the Bayesian setting to properly model the progression status of a patient (as determined by a group of expert clinicians) as a function of changes in spatially correlated sensitivities at each VF location jointly. We used a spatial probit regression model that jointly incorporates all highly correlated VF changes in a single framework while accounting for structural similarities between neighboring VF regions...
August 2016: Translational Vision Science & Technology
Jacob G Hillard, Thomas J Gast, Toco Y P Chui, Dan Sapir, Stephen A Burns
PURPOSE: Small artery and arteriolar walls thicken due to elevated blood pressure. Vascular wall thickness show a correlation with hypertensive subject history and risk for stroke and cardiovascular events. METHODS: The inner and outer diameter of retinal arterioles from less than 10 to over 150 μm were measured using a multiply scattered light adaptive optics scanning laser ophthalmoscope (AOSLO). These measurements were made on three populations, one with habitual blood pressures less than 100/70 mm Hg, one with normal blood pressures without medication, and one with managed essential hypertension...
August 2016: Translational Vision Science & Technology
Ian C Murray, Lorraine A Cameron, Alice D McTrusty, Antonios Perperidis, Harry M Brash, Brian W Fleck, Robert A Minns
PURPOSE: To evaluate feasibility, accuracy, and repeatability of suprathreshold Saccadic Vector Optokinetic Perimetry (SVOP) by comparison with Humphrey Field Analyzer (HFA) perimetry. METHODS: The subjects included children with suspected field defects (n = 10, age 5-15 years), adults with field defects (n = 33, age 39-78 years), healthy children (n = 12, age 6-14 years), and healthy adults (n = 30, age 16-61 years). The test protocol comprised repeat suprathreshold SVOP and HFA testing with the C-40 test pattern...
August 2016: Translational Vision Science & Technology
John Maguire, Neil R A Parry, Jan Kremers, Deepika Kommanapalli, Ian J Murray, Declan J McKeefry
PURPOSE: To demonstrate that silent substitution stimuli can be used to generate electroretinograms (ERGs) that effectively isolate rod photoreceptor function in humans without the need for dark adaptation, and that this approach constitutes a viable alternative to current clinical standard testing protocols. METHODS: Rod-isolating and non-isolating sinusoidal flicker stimuli were generated on a 4 primary light-emitting diode (LED) Ganzfeld stimulator to elicit ERGs from participants with normal and compromised rod function who had not undergone dark-adaptation...
August 2016: Translational Vision Science & Technology
Carmelina Trimboli-Heidler, Kelly Vogt, Robert A Avery
PURPOSE: To determine the influence of volume averaging on retinal layer thickness measures acquired with spectral-domain optical coherence tomography (SD-OCT) in children. METHODS: Macular SD-OCT images were acquired using three different volume settings (i.e., 1, 3, and 9 volumes) in children enrolled in a prospective OCT study. Total retinal thickness and five inner layers were measured around an Early Treatment Diabetic Retinopathy Scale (ETDRS) grid using beta version automated segmentation software for the Spectralis...
August 2016: Translational Vision Science & Technology
Helena Giannakaki-Zimmermann, Despina Kokona, Sebastian Wolf, Andreas Ebneter, Martin S Zinkernagel
PURPOSE: Optical coherence tomography angiography (OCT-A) allows noninvasive visualization of retinal vessels in vivo. OCT-A was used to characterize the vascular network of the mouse retina and was compared with fluorescein angiography (FA) and histology. METHODS: In the present study, OCT-A based on a Heidelberg Engineering Spectralis system was used to investigate the vascular network in mice. Data was compared with FA and confocal microscopy of flat-mount histology stained with isolectin IB4...
August 2016: Translational Vision Science & Technology
Ehud Zamir, George Y X Kong, Tanya Kowalski, Michael Coote, Ghee Soon Ang
PURPOSE: We hypothesize that: (1) Anterior chamber depth (ACD) is correlated with the relative anteroposterior position of the pupillary image, as viewed from the temporal side. (2) Such a correlation may be used as a simple quantitative tool for estimation of ACD. METHODS: Two hundred sixty-six phakic eyes had lateral digital photographs taken from the temporal side, perpendicular to the visual axis, and underwent optical biometry (Nidek AL scanner). The relative anteroposterior position of the pupillary image was expressed using the ratio between: (1) lateral photographic temporal limbus to pupil distance ("E") and (2) lateral photographic temporal limbus to cornea distance ("Z")...
July 2016: Translational Vision Science & Technology
Gijsbert J Hötte, Peter J Schaafsma, Charl P Botha, Piotr A Wielopolski, Huibert J Simonsz
PURPOSE: Little is known about the way orbital fat slides and/or deforms during eye movements. We compared two deformation algorithms from a sequence of MRI volumes to visualize this complex behavior. METHODS: Time-dependent deformation data were derived from motion-MRI volumes using Lucas and Kanade Optical Flow (LK3D) and nonrigid registration (B-splines) deformation algorithms. We compared how these two algorithms performed regarding sliding and deformation in three critical areas: the sclera-fat interface, how the optic nerve moves through the fat, and how the fat is squeezed out under the tendon of a relaxing rectus muscle...
July 2016: Translational Vision Science & Technology
Zhichao Wu, Xavier Hadoux, Flora Hui, Marc G Sarossy, Jonathan G Crowston
PURPOSE: To determine the measure of the photopic negative response (PhNR) of the full-field electroretinogram (ERG) that exhibits the optimal level of test-retest repeatability, and examine its repeatability under different conditions using a handheld, nonmydriatic ERG system and self-adhering skin electrodes. METHODS: Multiple ERG recordings (using 200 sweeps each) were performed in both eyes of 20 normal participants at two different sessions to compare its coefficient of repeatability (CoR; where 95% of the test-retest difference is expected to lie) between different PhNR measures and under different testing conditions (within and between examiners, and between sessions)...
July 2016: Translational Vision Science & Technology
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