Search results for " Coherence"
showing 10 items of 429 documents
Optical Coherence Tomography Angiography of Optic Disc in Eyes With Primary Open-angle Glaucoma and Normal-tension Glaucoma.
2019
PURPOSE To examine vessel density (VD) properties of the optic nerve head in eyes with ocular hypertension (OHT), high-tension glaucoma (HTG), and normal-tension glaucoma (NTG) and to evaluate associations on structural parameters of retinal nerve fiber layer (RNFL). METHODS Three groups of patients with OHT (n=15), HTG (n=36), and NTG (n=22), and a healthy control group (n=23) were included in this study. Peripapillary VD and optic disc flow area were measured using optical coherence tomography angiography, and peripapillary RNFL (pRNFL) thickness was determined. Global and sectoral analysis of optic nerve head vasculature and pRNFL thickness were measured. RESULTS Glaucomatous eyes had lo…
Lens-vault analysis and its correlation with other biometric parameters using swept-source OCT
2021
Purpose To measure lens vault (LV) and to assess its correlation with various ocular parameters in healthy eyes, using for all measurements the same high-resolution swept-source optical coherence tomographer (SS-OCT). Methods We prospectively recruited 67 Caucasian healthy patients whose mean age was 41.9 ± 12.4 years; only their right eye was included in the study. Data were all recorded with the ANTERION SS-OCT and comprised, for each patient, 5 consecutive measurements of LV, anterior chamber depth (ACD), lens thickness (LT), axial length (AL), white-to-white (WTW) distance, central corneal thickness (CCT), anterior chamber volume (ACV) and spur-to-spur (STS) distance. Results Mean LV wa…
OCT for Assessing Artificial Tears Effectiveness in Contact Lens Wearers
2011
PURPOSE: To apply a commercially available high-resolution spectral domain optical coherence tomographer (SOCT) to assess the change in tear volume after application of a new artificial tears formulation specifically developed for contact lens (CL) users. METHODS: Twenty OD from young healthy CL wearers (mean age, 24.7 ± 3.5 years) with refractive errors ranging from -0.75 to -2.50 D (mean, -1.56 ± 0.69 D) were examined. All subjects were fitted with Focus Dailies CL (Ciba Vision), and two drops of Blink Contacts (AMO), lubricating formulation specifically developed for CL wearers, were instilled after baseline measures. Tear meniscus volume (TMV) was measured immediately after and 1 min, 1…
Behaviour of the phakic iris-claw intraocular lens (Artisan /Verisyse) during accommodation: an optical coherence biometry study.
2007
Purpose To evaluate variations in the position of the phakic iris claw lens (Artisan®, Verisyse®) and the natural crystalline lens during the accommodation process. Methods We measured changes in position of the iris claw lens and the crystalline lens during the accommodation using optical coherence biometry (AC Master®/Carl Zeiss Meditec, Germany) in 17 patients (28 eyes) with a phakic iris claw lens implanted for high myopia and/or myopic astigmatism. Accommodative effort was obtained using an internal optical target within the measuring device. Results There was a forward shift of the phakic iris claw lens with a mean of 70 μm (8–178 μm) of the optical path length (OPL). At the same time…
Chromatic and achromatic visual fields in relation to choroidal thickness in patients with high myopia: A pilot study
2018
Purpose. - To analyse the relationship between the choroidal thickness and the visual perception of patients with high myopia but without retinal damage. Methods. - All patients underwent ophthalmic evaluation including a slit lamp examination and dilated ophthalmoscopy, subjective refraction, best corrected visual acuity, axial length, optical coherence tomography, contrast sensitivity function and sensitivity of the visual pathways. Results. - We included eleven eyes of subjects with high myopia. There are statistical correlations between choroidal thickness and almost all the contrast sensitivity values. The sensitivity of magnocellular and koniocellular pathways is the most affected, an…
Serum neurofilament levels reflect outer retinal layer changes in multiple sclerosis
2021
Background: Serum neurofilament light chain (sNfL) and distinct intra-retinal layers are both promising biomarkers of neuro-axonal injury in multiple sclerosis (MS). We aimed to unravel the association of both markers in early MS, having identified that neurofilament has a distinct immunohistochemical expression pattern among intra-retinal layers. Methods: Three-dimensional (3D) spectral domain macular optical coherence tomography scans and sNfL levels were investigated in 156 early MS patients (female/male: 109/47, mean age: 33.3 ± 9.5 years, mean disease duration: 2.0 ± 3.3 years). Out of the whole cohort, 110 patients had no history of optic neuritis (NHON) and 46 patients had a previous…
Successful subretinal delivery and monitoring of MicroBeads in mice
2013
BACKGROUND: To monitor viability of implanted genetically engineered and microencapsulated human stem cells (MicroBeads) in the mouse eye, and to study the impact of the beads and/or xenogenic cells on retinal integrity. METHODOLOGY/PRINCIPAL FINDINGS: MicroBeads were implanted into the subretinal space of SV126 wild type mice using an ab externo approach. Viability of microencapsulated cells was monitored by noninvasive retinal imaging (Spectralis™ HRA+OCT). Retinal integrity was also assessed with retinal imaging and upon the end of the study by light and electron microscopy. The implanted GFP-marked cells encapsulated in subretinal MicroBeads remained viable over a period of up to 4 mont…
In-medium jet shape from energy collimation in parton showers: Comparison with CMS PbPb data at 2.76 TeV
2014
Abstract: We present the medium-modified energy collimation in the leading-logarithmic approximation (LLA) and next-to-leading-logarithmic approximation (NLLA) of QCD. As a consequence of more accurate kinematic considerations in the argument of the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) fragmentation functions (FFs) we find a new NLLA correction O ð α s Þ which accounts for the scaling violation of DGLAP FFs at small x . The jet shape is derived from the energy collimation within the same approximations and we also compare our calculations for the energy collimation with the event generators PYTHIA 6 and Y A JEM for the first time in this paper. The modification of jets by the …
Quasi-decadal signals of Sahel rainfall and West African monsoon since the mid-twentieth century
2013
[1] Sahel rainfall shows pronounced decadal variability and a negative trend between wet conditions in the 1950s–1960s and dry ones in the 1970s–1980s. Using continuous wavelet transform, the quasi-decadal variability (QDV) of rainfall reveals zonal contrasts. The highest QDV is identified in the 1950s–1960s over western Sahel and in the 1970s–1980s over eastern Sahel. The quasi-decadal atmospheric anomalies have been reconstructed using Fourier transform for the 1950s–1960s and the 1970s–1980s, respectively, and assessed by the composite analysis of the QDV phases for the periods before and after 1968. Over western Sahel, the rainfall QDV in the 1950s–1960s is related to the North Atlantic…
Spatial coherence and potential predictability assessment of intraseasonal statistics of wet and dry spells over Equatorial Eastern Africa
2012
The aim of this study was to derive components of the intraseasonal rainfall variations from the daily rainfall in the Equatorial Eastern Africa region and assess their spatial coherence, a pointer to their potential predictability. Daily rainfall observations from 36 stations distributed over Equatorial Eastern Africa and extending from 1962 to 2000 were used. The March to May and October to December periods commonly referred to as the long and short rainfall seasons respectively were considered. Seasonal and intraseasonal statistics at the local (station) level were first defined. The stations were also grouped into near-homogeneous (sub-regional) zones based on daily rainfall. Similarly,…