Search results for "Meridian"
showing 10 items of 42 documents
Curvature of iris profile in spectral domain optical coherence tomography and dependency to refraction, age and pupil size - the MIPH Eye&Health …
2016
Purpose Optical coherence tomography (OCT) of the anterior segment allows quantitative analysis of the geometry of the iris. We performed spectral domain OCT examinations in healthy emmetropic, hyperopic and myopic subjects to investigate iris curvature and its associations. Methods In a cross-sectional study, out of 4617 eyes (2309 subjects) those with refractive errors of +3 dioptres were identified by objective refraction. The iris was examined using the anterior segment mode of a spectral domain 3D OCT-2000 (Topcon Inc., Japan) in the temporal meridian, and OCT scans were investigated with respect to presence and amount of convex and concave iris configuration. Ninety-three eyes of 50 s…
Image quality and visual performance in the peripheral visual field following photorefractive keratectomy.
2002
ABSTRACT PURPOSE: A theoretical and experimental study was performed to assess the possible effects of photorefractive keratectomy (PRK) on retinal image quality and thresholds in the peripheral visual field. METHODS: Simple optical calculations suggest that although the quality of the retinal image at the fovea of the postoperative PRK eye may be comparable to that in an emmetropic eye, images in the peripheral field may be markedly worse, since peripheral ray bundles may pass partly through ablated and partly through unablated cornea, giving a simultaneous-vision bifocal effect. This would be expected to create an annular zone of confusion, so that light from two different directions in o…
Postoperative astigmatism and rotational stability after Artisan toric phakic intraocular lens implantation
2003
Abstract Purpose To evaluate deviations in the axis (intended versus achieved) and postoperative astigmatism after implantation of an Artisan toric phakic intraocular lens (IOL). Setting University Eye Hospital, Mainz, Germany. Methods This prospective study comprised 29 eyes with high ametropia and astigmatism. All eyes had uneventful implantation of a toric phakic IOL through a superior scleral tunnel incision at 12 o’clock. After a minimum of 6 months, the uncorrected visual acuity (UCVA), best correct visual acuity, refraction, and astigmatism were analyzed in all eyes. A multivariate analysis of postoperative astigmatism was performed. Results After a follow-up of at least 6 months, 95…
Technical note: a comparison of central and peripheral intraocular pressure using rebound tonometry
2007
Purpose: To compare central and peripheral intraocular pressure (IOP) readings obtained with rebound tonometry.Methods: Intraocular pressure was measured on the right eye of 153 patients (65 males, 88 females), aged from 21 to 85 years (mean +/- S.D., 55.5 +/- 15.2 years) with the ICare rebound tonometer at centre, and 2 mm from the limbus (in the nasal and temporal regions along the 0-180O corneal meridian).Results: Intraocular pressure values obtained with the ICare were 14.9 +/- 2.8; 14.1 +/- 2.5 and 14.5 +/- 2.7 mmHg at centre, nasal and temporal corneal locations, respectively. On average, nasal and temporal IOP readings were 0.75 and 0.37 mmHg lower than the central reading (p 0.05, r…
Visible and near-infrared multispectral analysis of geochemically measured rock fragments at the Opportunity landing site in Meridiani Planum
2010
[1] We have used visible and near-infrared Panoramic Camera (Pancam) spectral data acquired by the Opportunity rover to analyze 15 rock fragments at the Meridiani Planum landing site. These spectral results were then compared to geochemistry measurements made by the in situ instruments Mossbauer (MB) and Alpha Particle X-ray Spectrometer (APXS) to determine the feasibility of mineralogic characterization from Pancam data. Our results suggest that dust and alteration rinds coat many rock fragments, which limits our ability to adequately measure the mineralogy of some rocks from Pancam spectra relative to the different field of view and penetration depths of MB and APXS. Viewing and lighting …
Bounce Rock-A shergottite-like basalt encountered at Meridiani Planum, Mars
2011
Additional co-authors: Thanasis ECONOMOU, Steven P. GOREVAN, Brian C. HAHN, Gostar KLINGELHOFER, Timothy J. McCOY, Harry Y. McSWEEN Jr, Douglas W. MING, Richard V. MORRIS, Daniel S. RODIONOV, Steven W. SQUYRES, Heinrich WANKE, Shawn P. WRIGHT, Michael B. WYATT, Albert S. YEN
Fe Mossbauer spectroscopy as a tool in astrobiology
2006
The element Fe and Fe-bearing minerals occur ubiquitously throughout the field of astrobiology. Cycling between the various oxidation states of Fe provides a source of energy available for life. Banded iron formations may record the rise of oxygenic photosynthesis. The distribution of Fe between Fe-bearing minerals and its oxidation states can help to characterize and understand ancient environments with respect to the suitability for life by constraining the primary rock type and the redox conditions under which it crystallized, the extent of alteration and weathering, the type of alteration and weathering products, and the processes and environmental conditions for alteration and weatheri…
La pareja Bazo–Estómago y el trayecto de Zuyangming
2015
In this paper, we study the reason why Zuyangming (stomach meridian) travels the body through yin territory in contrast with the other eleven main meridians governed by the quantitative–qualitative yinyang synchronicity of meridians and territories to discover. Zuyangming meets this principle only partially (in face and leg) and that is why we attempt to decipher the reasons for this exception in the thoraco–abdominal trajectory. Ancient traditional medical texts describe the internal and external routes of meridians and the relations between the spleen–stomach pair, which Su Wen 8 transforms into spleenstomach, mentioning the membranous binding (connective tissue today) which unifies both …
Il Corridioio Meridiano come dispositivo territoriale per la competitività del Mezzogiorno
2008
Una nuova vision ha animato la redazione del Quadro Strategico Nazionale 2007-13 per il settore delle “infrastrutture e città”: una strategia reticolare di innovazione capace di orientare interventi di costituzione di cluster produttivi e innovativi, di connessione di piattaforme, di ricentralizzazione di aree urbane attraverso la riqualificazione dei nodi e la dotazione di servizi collettivi. La strategia mira soprattutto alla ridefinizione di funzioni di rango metropolitano in grado di potenziare il ruolo di Global Gateways che le città stanno progressivamente assumendo all'interno dei processi più avanzati di rigenerazione urbana e competitività territoriale, capaci di agire da “trasform…
Changes in physiological astigmatism of human eye during accommodation in emmetropes (Conference Presentation)
2017
Introduction: Most young emmetrope eyes are far from ideal and have some degree of minor spherocylindrical error including also physiological astigmatism. Because of the changes in the shape of optical interfaces, pupil size, eyelid pressure, tear film, body posture, binocularity and accommodation astigmatism is considered as constantly dynamic phenomenon (Cheng et al, 2004). The purpose of this study was to evaluate and quantify changes in physiological astigmatism during accommodation. Method: Twenty young emmetropes with mean age 24 ± 4 years were selected for the study. Refraction and accommodative response were measured monocularly for dominant eye with an open-field infrared autorefract…