1. Articles in category: Ophthalmology

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    1. Imaging pulsatile retinal blood flow in human eye

      Bin Rao, Lingfeng Yu, Huihua Kenny Chiang et al. A functional Fourier domain optical coherence tomography instrument offering spectral Doppler imaging of in vivo pulsatile human retinal blood flow was constructed. An improved phase-resolved algorithm was developed to correct bulk motion artifacts. Spectral Doppler imaging provides complementary te ... [J. Biomed. Opt. 13, 040505 (2008)] published Mon Aug 25, 2008.
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    2. Relationship of the optical coherence tomography signal to underlying retinal histology in the tree shrew (Tupaia belangeri)

      PURPOSE. To interpret the retinal origin of the optical coherence tomography (OCT) signal by objectively (i.e. minimal investigator bias) aligning in vivo OCT longitudinal reflectivity profiles (LRPs) with corresponding vertical histological sections. METHODS. The Zeiss StratusOCT system was used to obtain retinal B-scans in vivo in eyes from adult tree shrews. Subsequently, the retinas were fixed and embedded. Semi-thin vertical sections through the retina were obtained from the same locations as the LRPs. A statistical correlation procedure that accounted for axial tissue shrinkage determined the best relationship between features in the LRP and sublaminae boundaries in corresponding histology sections ...
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    3. Intra-observer and Inter-observer Reliability and Reproducibility of Slit-Lamp–Adapted Optical Coherence Tomography for Evaluation of Anterior Chamber Depth and Central Corneal Thickness

      BACKGROUND AND OBJECTIVE To evaluate the intra-observer and inter-observer reproducibility of anterior chamber depth (ACD) and central corneal thickness (CCT) measurements taken by slit-lamp–adapted optical coherence tomography (SL-OCT) and to evaluate concordance of CCT and ACD values obtained by SL-OCT with gold standard devices. PATIENTS AND METHODS Three images of each eye were taken by two different operators using SL-OCT. ACD and CCT values obtained by each operator were determined and compared to one another and to ultrasonic pachymetry (CCT) and axial OCT biometry (ACD) values obtained by a third, masked operator. Intra-observer and inter-operator reproducibility was assessed using ...
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    4. Correlation between structural and functional analysis in glaucoma suspects

      [Correlation between structural and functional analysis in glaucoma suspects] Oftalmologia. 2008;52(1):111-8 Authors: Chiseliţă D, Danielescu C, Apostol A PURPOSE: To establish correlations between structural and functional parameters in glaucoma suspects. METHOD: In 43 patients (83 eyes) of glaucoma patients we have performed standard automated perimetry, scanning laser polarimetry (GDx-VCC) of the retinal nerve fiber layer (RNFL) and optical coherence tomography (Stratus OCT) of the RNFL and optic disc. RESULTS: Diagnostic concordance (achieved if one eye is deemed normal--respectively abnormal--by both tests) was 60.24% between perimetry and OCT respectively 61.44% between perimetry and GDx. The Areas ...
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    5. Evaluating subconjunctival bleb function after trabeculectomy using slit-lamp optical coherence tomography and ultrasound biomicroscopy

      Background The existing classifications for evaluating glaucoma filtering blebs rely mostly on external bleb characteristics and the postoperative control of intraocular pressure (IOP). Internal bleb structures are not carefully observed. This study aimed to analyze and compare glaucoma filtering bleb morphology using slit-lamp-adapted optical coherence tomography (SL-OCT) and ultrasound biomicroscopy (UBM), and to classify blebs according to results and intraocular pressure. Methods We followed 29 eyes of 21 male patients and 40 eyes of 32 female patients who underwent glaucoma filtering surgery in Sixth People’s Hospital of Shanghai, between 2002 and 2006. The blebs were imaged using SL-OCT and ...
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    6. Corneal birefringence mapped by scanning laser polarimetry

      Corneal birefringence mapped by scanning laser polarimetry
      Corneal birefringence affects polarization-sensitive optical measurements of the eye. Recent literature supports the idea that corneal birefringence is biaxial, although with some disagreement among reports and without considering corneas with very low values of central retardance. This study ... [Opt. Express 16, 13738-13751 (2008)]
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    7. Optical coherence tomography findings in hemodialysis patients

      Related Articles [Optical coherence tomography findings in hemodialysis patients] Klin Monatsbl Augenheilkd. 2008 Aug;225(8):713-7 Authors: Pahor D, Gracner B, Gracner T, Hojs R BACKGROUND: The aim of the present prospective study was to compare retinal thickness between normal healthy subjects and chronic renal failure patients treated with maintenance hemodialysis (HD) as well as to determine whether there was any correlation between age and duration of HD treatment. PATIENTS AND METHODS: A total of 24 eyes of 12 HD patients and 32 eyes of 16 controls underwent optical coherence tomographic scanning (OCT) in the central disc of 6000 ...
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    8. Evaluating subconjunctival bleb function after trabeculectomy using slit-lamp optical coherence tomography and ultrasound biomicroscopy.

      Related Articles Evaluating subconjunctival bleb function after trabeculectomy using slit-lamp optical coherence tomography and ultrasound biomicroscopy. Chin Med J (Engl). 2008 Jul 20;121(14):1274-9 Authors: Zhang Y, Wu Q, Zhang M, Song BW, DU XH, Lu B BACKGROUND: The existing classifications for evaluating glaucoma filtering blebs rely mostly on external bleb characteristics and the postoperative control of intraocular pressure (IOP). Internal bleb structures are not carefully observed. This study aimed to analyze and compare glaucoma filtering bleb morphology using slit-lamp-adapted optical coherence tomography (SL-OCT) and ultrasound biomicroscopy (UBM), and to classify blebs according to results and intraocular pressure ...
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    9. Thickness Profiles of Retinal Layers by Optical Coherence Tomography Image Segmentation

      To report an image segmentation algorithm that was developed to provide quantitative thickness measurement of six retinal layers in optical coherence tomography (OCT) images. Design Prospective cross-sectional study. Methods Imaging was performed with time- and spectral-domain OCT instruments in 15 and 10 normal healthy subjects, respectively. A dedicated software algorithm was developed for boundary detection based on a 2-dimensional edge detection scheme, enhancing edges along the retinal depth while suppressing speckle noise. Automated boundary detection and quantitative thickness measurements derived by the algorithm were compared with measurements obtained from boundaries manually marked by three observers. Thickness profiles for six retinal ...
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    10. Optical coherence tomography of clear corneal incisions for cataract surgery

      Purpose To study the architecture of clear corneal incisions for phacoemulsification cataract surgery using optical coherence tomography (OCT). Setting Doheny Eye Institute and Department of Ophthalmology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA. Methods This prospective study comprised 20 eyes of 20 patients 1 month after cataract surgery performed by 1 of 2 experienced surgeons. Temporal clear corneal single-plane incisions were made with 3.0 mm metal keratomes. Each eye was scanned before and 1 month after surgery with a prototype high-speed anterior segment OCT system (Carl Zeiss Meditec, Inc.). The OCT scans ...
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    11. Optical Coherence Tomography for Classification and Clinical Evaluation of Macular Edema in Patients with Uveitis

      Purpose: To study use of optical coherence tomography (OCT) for macular edema in uveitis. Methods: In total, 44 patients with uveitis and macular edema underwent OCT. Data obtained were correlated with anatomic type, duration of uveitis, and visual acuity (VA). Results: Both cystoid macular edema (CME) and diffuse macular edema (DME) correlate negatively with VA, although statistically CME showed stronger correlation (p = .02). Also CME had higher mean foveal thickness than DME (p

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    12. Lens thickness with age and accommodation by optical coherence tomography

      Purpose: To utilize time-domain optical coherence tomography (OCT) to measure changes in the crystalline lens with age and accommodation.Methods: A cross-sectional study of pre-presbyopic and presbyopic subjects was conducted. Amplitude of accommodation was measured with the push-up test. Objective accommodation was measured with the Grand Seiko auto-refractor and a Badal lens system. Lens thickness was measured with the Zeiss Visante OCT and an internal optometer. The data were analysed using correlation coefficients, linear regression, and by calculating the average change in lens thickness per diopter change in objective accommodation.Results: Twenty-two subjects between the ages of 36 and 50 ...
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    13. Disruption of the Photoreceptor Inner Segment-Outer Segment Junction in Eyes With Macular Holes

      Purpose: To examine the relationship between visual acuity and morphologic characteristics of macular holes as determined using spectral domain optical coherence tomography (SD OCT). Methods: A retrospective analysis was performed of eyes with open and closed macular holes at a single, referral-based retina practice. The main outcome measures included best-corrected Snellen visual acuity and SD OCT findings, including the size of the macular hole and the disruption of the junction between inner segments (ISs) and outer segments (OSs) of the photoreceptors. Results: The mean visual acuity for eyes with open (n = 24) and closed (n = 17) macular holes was 20 ...
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    14. A review of in vivo animal studies in retinal prosthesis research

      Background The development of a functional retinal prosthesis for acquired blindness is a great challenge. Rapid progress in the field over the last 15 years would not have been possible without extensive animal experimentation pertaining to device design and fabrication, biocompatibility, stimulation parameters and functional responses. This paper presents an overview of in vivo animal research related to retinal prosthetics, and aims to summarize the relevant studies. Methods A Pubmed search of the English language literature was performed. The key search terms were: retinal implant, retinal prosthesis, artificial vision, rat, rabbit, cat, dog, sheep, pig, minipig. In addition a manual ...
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    15. Ultrasound provides clearer picture of posterior segment

      "Currently available ultrasound techniques can evaluate the cornea to the level of microns. By imaging the sulcus, ciliary body, and lens, the results are superior to OCT imaging," he said. "For retina specialists, this technology is useful for looking at the anterior segment, that is, the ciliary body and the area around the lens. This imaging approach is also useful to diagnose and follow patients with tumors to determine if treatment with an iodine or other radioactive plaque is necessary or, if used, was effective. However, the posterior segment cannot be visualized using high frequencies because of ultrasound absorption, thus ...
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    16. Spectral-domain optical coherence tomography an improvement over previous optical coherence tomography systems

      Spectral-domain optical coherence tomography (SD-OCT) offers several major advantages over conventional OCT: faster image acquisition time, improved resolution, and improved image processing. In addition, the technology decreases patient motion artifact, which is especially useful when obtaining images in children.
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    17. Automated system separates glaucomatous, healthy eyes

      An automated glaucoma risk indicator using digital color fundus photos proved to be accurate in the detection of glaucoma disease in a recent study. This novel technique is not intended to replace other state-of-the-art diagnostic techniques currently used . Ophthalmologists, however, can receive a confirmation from this automated diagnosing system that the diagnosis they are making in regards to glaucoma is the right one.
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    18. Fourier-domain optical coherence tomography allows improved visualization of retinal layers

      Sacramento, CA—Fourier-domain optical coherence tomography (OCT) is a new technology that enables improved visualization of the retinal layers, especially the photoreceptor layer. This technology, also known as spectral-domain OCT, is sensitive enough to facilitate the diagnosis of maculopathy in eyes with vision loss unexplained using routine diagnostic tests, such as funduscopy, fluorescein angiography, and time-domain OCT technology (Stratus OCT, Carl Zeiss Meditec). So says Susanna S. Park, MD, PhD, who with colleagues used for research a high-resolution Fourier-domain OCT instrument developed by the Vision Science and Advanced Retinal Imaging Laboratory at the University of California Davis. The system differs ...
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