The Experts below are selected from a list of 1509 Experts worldwide ranked by ideXlab platform

Patrick Hardigan - One of the best experts on this subject based on the ideXlab platform.

  • More sensitive correlation of afferent pupillary defect with ganglion cell complex
    Elsevier, 2018
    Co-Authors: Eulogio Besada, Barry J. Frauens, Rim Makhlouf, Diana Shechtman, Julie Rodman, Marlon Demeritt, Patrick Hardigan
    Abstract:

    Purpose: This study investigated the correlation between the relative afferent pupillary defect (RAPD) and retinal nerve fiber layer thickness (RNFLT) in optic neuropathy. Methods: RAPD assessment was performed using a log unit Neutral Density Filter bar. Spectral domain optical coherence tomography RTVue-100 (Optovue) was used to examine the subjects. The optic nerve head pattern (ONH) was subdivided and identified for the purpose of the study into circumpapillary RNFLT (cpRNFLT) and peripheral circumpapillary RNFLT (pcpRNFLT). The cpRNFLT, pcpRNFLT and ganglion cell complex (GCC) parameters were analyzed. Results: Eighteen females and twenty three males with asymmetric optic neuropathy and a RAPD participated. Thirty-three subjects had glaucoma and eight had optic neuropathy other than glaucoma. Significant correlations (p 

  • more sensitive correlation of afferent pupillary defect with ganglion cell complex
    Journal of Optometry, 2017
    Co-Authors: Eulogio Besada, Barry J. Frauens, Rim Makhlouf, Diana Shechtman, Julie Rodman, Marlon Demeritt, Patrick Hardigan
    Abstract:

    Abstract Purpose This study investigated the correlation between the relative afferent pupillary defect (RAPD) and retinal nerve fiber layer thickness (RNFLT) in optic neuropathy. Methods RAPD assessment was performed using a log unit Neutral Density Filter bar. Spectral domain optical coherence tomography RTVue-100 (Optovue) was used to examine the subjects. The optic nerve head pattern (ONH) was subdivided and identified for the purpose of the study into circumpapillary RNFLT (cpRNFLT) and peripheral circumpapillary RNFLT (pcpRNFLT). The cpRNFLT, pcpRNFLT and ganglion cell complex (GCC) parameters were analyzed. Results Eighteen females and twenty three males with asymmetric optic neuropathy and a RAPD participated. Thirty-three subjects had glaucoma and eight had optic neuropathy other than glaucoma. Significant correlations ( p p Conclusions Significant correlations between RNFLT loss for cpRNFLT, pcpRNFLT and GCC parameters with RAPD were observed. Approximately a 35% higher sensitivity was obtained using GCC compared to CRNFL parameters. The expected change in GCC average for every 0.3 log unit increment was approximately 8.49 μm. The FLV% corresponded more sensitively to a RAPD but appeared to be influenced by disease severity.

Kishan Dholakia - One of the best experts on this subject based on the ideXlab platform.

  • multi photon attenuation compensated light sheet fluorescence microscopy
    Scientific Reports, 2020
    Co-Authors: Madhu Veettikazhy, Jonathan Nylk, Federico M Gasparoli, Adria Escobetmontalban, Anders Kragh Hansen, Dominik Marti, Peter Andersen, Kishan Dholakia
    Abstract:

    Attenuation of optical fields owing to scattering and absorption limits the penetration depth for imaging. Whilst aberration correction may be used, this is difficult to implement over a large field-of-view in heterogeneous tissue. Attenuation-compensation allows tailoring of the maximum lobe of a propagation-invariant light field and promises an increase in depth penetration for imaging. Here we show this promising approach may be implemented in multi-photon (two-photon) light-sheet fluorescence microscopy and, furthermore, can be achieved in a facile manner utilizing a graded Neutral Density Filter, circumventing the need for complex beam shaping apparatus. A “gold standard” system utilizing a spatial light modulator for beam shaping is used to benchmark our implementation. The approach will open up enhanced depth penetration in light-sheet imaging to a wide range of end users.

Eulogio Besada - One of the best experts on this subject based on the ideXlab platform.

  • More sensitive correlation of afferent pupillary defect with ganglion cell complex
    Elsevier, 2018
    Co-Authors: Eulogio Besada, Barry J. Frauens, Rim Makhlouf, Diana Shechtman, Julie Rodman, Marlon Demeritt, Patrick Hardigan
    Abstract:

    Purpose: This study investigated the correlation between the relative afferent pupillary defect (RAPD) and retinal nerve fiber layer thickness (RNFLT) in optic neuropathy. Methods: RAPD assessment was performed using a log unit Neutral Density Filter bar. Spectral domain optical coherence tomography RTVue-100 (Optovue) was used to examine the subjects. The optic nerve head pattern (ONH) was subdivided and identified for the purpose of the study into circumpapillary RNFLT (cpRNFLT) and peripheral circumpapillary RNFLT (pcpRNFLT). The cpRNFLT, pcpRNFLT and ganglion cell complex (GCC) parameters were analyzed. Results: Eighteen females and twenty three males with asymmetric optic neuropathy and a RAPD participated. Thirty-three subjects had glaucoma and eight had optic neuropathy other than glaucoma. Significant correlations (p 

  • more sensitive correlation of afferent pupillary defect with ganglion cell complex
    Journal of Optometry, 2017
    Co-Authors: Eulogio Besada, Barry J. Frauens, Rim Makhlouf, Diana Shechtman, Julie Rodman, Marlon Demeritt, Patrick Hardigan
    Abstract:

    Abstract Purpose This study investigated the correlation between the relative afferent pupillary defect (RAPD) and retinal nerve fiber layer thickness (RNFLT) in optic neuropathy. Methods RAPD assessment was performed using a log unit Neutral Density Filter bar. Spectral domain optical coherence tomography RTVue-100 (Optovue) was used to examine the subjects. The optic nerve head pattern (ONH) was subdivided and identified for the purpose of the study into circumpapillary RNFLT (cpRNFLT) and peripheral circumpapillary RNFLT (pcpRNFLT). The cpRNFLT, pcpRNFLT and ganglion cell complex (GCC) parameters were analyzed. Results Eighteen females and twenty three males with asymmetric optic neuropathy and a RAPD participated. Thirty-three subjects had glaucoma and eight had optic neuropathy other than glaucoma. Significant correlations ( p p Conclusions Significant correlations between RNFLT loss for cpRNFLT, pcpRNFLT and GCC parameters with RAPD were observed. Approximately a 35% higher sensitivity was obtained using GCC compared to CRNFL parameters. The expected change in GCC average for every 0.3 log unit increment was approximately 8.49 μm. The FLV% corresponded more sensitively to a RAPD but appeared to be influenced by disease severity.

Kai Januschowski - One of the best experts on this subject based on the ideXlab platform.

  • Associating the magnitude of relative afferent pupillary defect (RAPD) with visual field indices in glaucoma patients.
    The British journal of ophthalmology, 2012
    Co-Authors: Ulrich Schiefer, Helmut Wilhelm, Janko Dietzsch, B. Wilhelm, Klaus Dietz, A. Bruckmann, Veronique Kitiratschky, Kai Januschowski
    Abstract:

    Purpose To identify the variable with the strongest association between the magnitude of the relative afferent pupillary defect (RAPD) and visual field indices in patients with glaucomatous optic neuropathy. Methods Seventy-nine consecutive subjects with manifest glaucomatous optic neuropathy at least in one eye were enrolled in this retrospective study. RAPD was assessed with the swinging flashlight test and quantified with a Neutral Density Filter. Perimetry was performed using the fast thresholding strategy German Adaptive Threshold Estimation. The values of the central differential luminance sensitivity (DLS), of the MD (mean defect) and of the ‘loss volume’ (LVOL) based on the individually modelled 3D hill of vision—the latter two within the eccentricities of 10°, 20° and 30°, respectively—were entered into a linear regression model without intercept as a function of RAPD. Results An absolute value of RAPD of 0.3 log 10 units or more was present in 20 out of 79 glaucoma subjects (25%). The magnitude of RAPD was most closely associated with LVOL-30° (R 2 =0.77), followed by MD-30° (R 2 =0.73), MD-20° (R 2 =0.71), LVOL-20° (R 2 =0.67), MD-10° (R 2 =0.58), LVOL-10° (R 2 =0.54) and central DLS (R 2 =0.04). Conclusions The prevalence of RAPD in glaucoma patients is comparatively small (25%). The magnitude of RAPD in glaucoma subjects is associated most closely with the LVOL within 30° eccentricity (which is the maximum visual field region tested in this study) and most loosely with central DLS, underscoring the impact of the entire (30°) visual field area on the afferent pupillary system.

Mercedes Lopezmorales - One of the best experts on this subject based on the ideXlab platform.

  • limits to transits of the neptune mass planet orbiting gj 581
    Publications of the Astronomical Society of the Pacific, 2006
    Co-Authors: Mercedes Lopezmorales, Nidia Morrell, Paul R Butler, Sara Seager
    Abstract:

    We have monitored the Neptune‐mass, exoplanet‐hosting M dwarf GJ 581 with the 1 m Swope Telescope at Las Campanas Observatory over two predicted transit epochs. A Neutral Density Filter centered at 550 nm was used during the first epoch, yielding 6.33 hr of continuous light‐curve coverage with an average photometric precision of 1.6 mmag and a cadence of 2.85 minutes. The second epoch was monitored in the B band over 5.85 hr, with an average photometric precision of 1.2 mmag and a 4.28 minute cadence. No transits are apparent on either night, indicating that the orbital inclination is less than 88 1 for all planets with radii larger than 0.38RNep (=1.48 R⊕). Because planets with the most likely interior compositions will have radii larger than 1.55 R⊕, we place an inclination limit of 88 1 for the system. The corresponding minimum mass of the exoplanet GJ 581b remains 0.97 MNep (=16.6 R⊕).

  • limits to transits of the neptune mass planet orbiting gl 581
    arXiv: Astrophysics, 2006
    Co-Authors: Mercedes Lopezmorales, Nidia Morrell, Paul R Butler, Sara Seager
    Abstract:

    We have monitored the Neptune-mass exoplanet-hosting M-dwarf Gl 581 with the 1m Swope Telescope at Las Campanas Observatory over two predicted transit epochs. A Neutral Density Filter centered at 550nm was used during the first epoch, yielding 6.33 hours of continuous light curve coverage with an average photometric precision of 1.6 mmags and a cadence of 2.85 min. The second epoch was monitored in B-band over 5.85 hours, with an average photometric precision of 1.2 mmags and 4.28 min cadence. No transits are apparent on either night, indicating that the orbital inclination is less than 88.1 deg for all planets with radius larger than 0.38 R_Nep = 1.48 R_Earth. Because planets of most reasonable interior composition have radii larger than 1.55 R_Earth we place an inclination limit for the system of 88.1 deg. The corresponding minimum mass of Gl 581b remains 0.97 M_Nep = 16.6 M_Earth.