Search results for " Crystal"
showing 10 items of 3073 documents
Comparison of biometric measurements using partial coherence interferometry and applanation ultrasound
2003
Abstract Purpose To compare and contrast axial length (AL) measurements assessed by ultrasound biometry and optical biometry. Setting Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. Methods Optical biometry and ultrasound biometry were performed in 360 eyes to measure AL. Results In eyes with a clear-appearing crystalline lens, there was a statistically significant median difference in AL measurements between the 2 methods in eyes with a normal or long length. In eyes with cataract, there was a statistically significant median difference in AL measurements in eyes with a normal or short length. In these cases, optical biometry produced larger readings than ultras…
Spring constants of capsular tension rings.
2004
Purpose To determine the spring constants of several types of capsular tension rings (CTRs). Setting Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. Methods Fourteen models of CTRs provided by 9 companies were tested; all were 11.0 mm in diameter. The CTRs were positioned in a special retainer of a material-testing machine and compressed at a constant speed of 10.0 mm per minute. The distance and force values were recorded, and each CTR model was tested 3 times using a new specimen each time. The resulting measurements were used to calculate a mean spring constant for each CTR model. Results All tested CTRs showed linear proportionality between force and compress…
Diffuse reflectance and fluorescence multispectral imaging system for assessment of skin
2014
The diffuse reflectance multispectral imaging technique has been used for distant mapping of in vivo skin chromophores (hemoglobin and melanin). The fluorescence multispectral imaging is not so common for skin applications due to complicity of data acquisition and processing, but could provide additional information about skin fluorophores. Both techniques are compatible, and could be combined into a multimodal solution. The multispectral imaging system Nuance based on liquid crystal tunable filters was adapted for diffuse reflectance and fluorescence spectral imaging of in vivo skin. Uniform illumination was achieved by LED ring light. Combination of four LEDs (warm white, 770 nm, 830 nm a…
Practical recommendations for the application of DE 59/2013
2019
The changes introduced with Council Directive 2013/59/Euratom will require European Member States adapt their regulations, procedures and equipment to the new high standards of radiation safety. These new requirements will have an impact, in particular, on the radiology community (including medical physics experts) and on industry. Relevant changes include new definitions, a new dose limit for the eye lens, non-medical imaging exposures, procedures in asymptomatic individuals, the use and regular review of diagnostic reference levels (including interventional procedures), dosimetric information in imaging systems and its transfer to the examination report, new requirements on responsibiliti…
Changes in higher-order aberrations after implantation of a foldable iris-claw lens in myopic phakic eyes
2006
Purpose To evaluate the change in higher-order aberrations (HOAs) after implantation of a foldable iris-claw phakic intraocular lens (pIOL) in myopic eyes. Setting Department of Ophthalmology, Johannes Gutenberg-University, Mainz, Germany. Methods This prospective nonrandomized comparative self-controlled trial included 41 eyes that had implantation of a foldable iris-claw pIOL between July 2003 and November 2004. All patient data for HOAs (Zernike coefficient) were measured and calculated using the same pupil size preoperatively and postoperatively, and the root-mean-square (RMS) wavefront error was calculated. Examinations were performed preoperatively as well as 1 week and 3, 6, and 12 m…
Albumin replacement therapy in immunocompromised patients with sepsis - Secondary analysis of the ALBIOS trial
2021
Abstract Background The best fluid replacement strategy and the role of albumin in immunocompromised patients with sepsis is unclear. Methods We performed a secondary analysis of immunocompromised patients enrolled in the ALBIOS trial which randomized patients with severe sepsis or septic shock to receive either 20% albumin (target 30 g per liter or more) and crystalloid or crystalloid alone during ICU stay. Results Of 1818 patients originally enrolled, 304 (16.4%) were immunocompromised. One-hundred-thirty-nine (45.7%) patients were randomized in the albumin while 165 (54.2%) in the crystalloid group. At 90 days, 69 (49.6%) in the albumin group and 89 (53.9%) in the crystalloids group died…
Past and present work practices of European interventional cardiologists in the context of radiation protection of the eye lens—results of the EURALO…
2018
International audience; This paper investigates over five decades of work practices in interventional cardiology, with an emphasis on radiation protection. The analysis is based on data from more than 400 cardiologists from various European countries recruited for a EURALOC study and collected in the period from 2014 to 2016. Information on the types of procedures performed and their annual mean number, fluoroscopy time, access site choice, x-ray units and radiation protection means used was collected using an occupational questionnaire. Based on the specific European data, changes in each parameter have been analysed over decades, while country-specific data analysis has allowed us to dete…
Postoperative Lens Position Preoperatively Determined by Scheimpflug Photography
1999
The position of the artificial lens has an important influence on refractive power calculation. We compared the position of the crystalline lens with that of the artificial lens after cataract surgery by means of Scheimpflug photography. A difference in position of approximately 0.8 mm in the anterior direction could be determined.
Optical quality of the diabetic eye: a review
2014
Diabetes mellitus is a metabolic disorder characterized by the presence of chronic hyperglycaemia. Several structural, morphological, and physiological changes in each of ocular component have been described in detail during the past decades. Due to these abnormalities, the diabetic patient undergoes a degradation of the retinal image by an increase of higher ocular aberrations and ocular scattering coming from mainly tear film, cornea, and crystalline lens. This review aims to provide an overview of current knowledge about the effects of diabetes mellitus in these optical phenomena and its consequence on the visual quality of the diabetic patient.
Lens implant selection with absence of capsular support.
2001
If contact lens or spectacle correction is not viable, little debate exists that the secondary placement of an intra-ocular lens (IOL) is the method of choice in the absence of capsular support. The choice of IOL mainly depends on the preoperative status of the eye (eg, aphakia in children) and the selected location for the implant. Theoretically, there are several IOL implantation approaches in cases without capsular support: an angle-supported anterior chamber (AC) IOL, an iris-fixated ACIOL, an iris-sutured or iris-fixated posterior chamber (PC) IOL and a transsclerally sutured PCIOL. No consensus exists, however, on the indications as well as on the relative safety and efficacy of these…