1,376 research outputs found
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'You've got dry macular degeneration, end of story': a qualitative study into the experience of living with non-neovascular age-related macular degeneration.
BACKGROUND/OBJECTIVES: To investigate the impact of non-neovascular (dry) age-related macular degeneration (AMD) on the person with respect to diagnosis, vision loss and coping strategies.
SUBJECTS/METHODS: Volunteers with dry AMD with a range of disease severity were given an eye examination and asked to describe aspects of their experience with dry AMD in a semi-structured interview. Interviews were audio-recorded, transcribed, and subjected to Framework analysis. Overarching themes were pre-defined, whilst subthemes were derived from the data. RESULTS: Twenty-seven participants (81% female), with early (n = 3), intermediate (n = 16) and advanced dry AMD (GA; n = 8) were interviewed. Median (interquartile range) age (years), logMAR binocular visual acuity and Pelli-Robson contrast sensitivity were 76 (71, 80), 0.2 (0.18, 0.40) and 1.65 (1.35, 1.93), respectively. Overarching themes (and subthemes) were: diagnosis (relationship with healthcare professional, psychological impact of diagnosis, and knowledge of AMD, both pre- and post-diagnosis), impact of visual loss (functional and psychological) and coping strategies (help from others and personal strategies). Many participants reported feelings of distress at the time of diagnosis and, particularly noteworthy, several reported a constant fear of their condition worsening.
CONCLUSIONS: Dry AMD, for which there is currently no treatment, can have a significant impact on individuals, even in its early stages, before significant functional vision loss is manifest, as well as in its intermediate and advanced stages. Results from this study offer important insight into the experience of living with dry AMD not previously explored. Moreover, the results have the potential to serve as an educational resource for eyecare professionals
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Seeing it differently: self-reported description of vision loss in dry age-related macular degeneration
PURPOSE: A realistic description of visual symptoms associated with dry age-related macular degeneration (AMD) is important for raising awareness of the condition and educating patients. This study aimed to develop a set of descriptors for dry AMD and examine the realism of images currently and frequently used to show visual symptoms of the condition. METHODS: Volunteers with dry AMD with a range of disease severity were given an eye examination and were asked to describe visual symptoms of their condition in a conversational interview. Participants were also asked to comment on a photograph typically used to portray the visual symptoms of AMD. Interviews were audio recorded, transcribed and subjected to content analysis. RESULTS: Twenty-nine participants were interviewed. Median (interquartile range [IQR]) age was 75 (70, 79) years. Median (IQR) binocular visual acuity (VA) and Pelli-Robson contrast sensitivity (CS) was 0.2 (0.18, 0.36) logMAR and 1.65 (1.50, 1.95) log CS respectively. Three, 17 and nine patients had early, intermediate and late (geographic atrophy, GA) AMD, respectively. The most frequently reported descriptor group was blur (n = 13) followed by missing (n = 10) and distortion (n = 7). We chose the most popular image used to portray the visual symptoms of dry AMD based on an internet search and showed this to 21 participants. Sixteen participants (76% [95% confidence interval 53-92%]), including three out of the seven people with geographic atrophy, unequivocally rejected the realism of the image. CONCLUSIONS: People with dry AMD use a wide range of descriptors for their visual experience. Visual symptoms of dry AMD as portrayed by commonly shown images were not the experience of most people in this study
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Determining Optimal Test Parameters for Assessing Dark Adaptation in People With Intermediate Age-Related Macular Degeneration
Purpose: The primary aim was to determine optimal test conditions for evaluating dark adaptation in intermediate age-related macular degeneration (iAMD) in order to minimize test time while maintaining diagnostic sensitivity.
Methods: People with AMD and age-similar controls were recruited (aged >55 years). Rod intercept time (RIT) was assessed after a 76%, 70%, and 65% rhodopsin bleach at 5° eccentricity and 76% and 70% bleach at 12°. Test order was randomized and a 30-minute washout period added between tests. Results were compared between control and iAMD groups and receiver operating characteristics (ROC) curves were constructed.
Results: A total of 26 participants with variable grades of macular health attended for two visits. There was a statistically significant difference in average RIT between the control and iAMD groups at 5° (median, IQR controls = 5.8 minutes, 3.8–7.5; iAMD = 20.6 minutes, 11.1–30.0; Mann-Whitney, P = 0.01) and at 12° (mean, controls: 4.54 minutes ± 2.12 SD, iAMD = 7.72 minutes ± 3.37 SD; independent samples t-test, P = 0.03) following a 76% bleach. Area under the ROC curves was 0.83 (confidence interval [CI]: 0.64–1.0) and 0.79 (CI: 0.59–0.99) for these two test conditions, respectively. Five participants (45%) in the iAMD group had RITs >20 minutes for 76% bleach at 5°, but none for any other test condition.
Conclusions: Nearly half of the participants with iAMD produced unacceptably long recovery times (>20 minutes) using a 76% bleach at 5° eccentricity. The 76% bleach at 12° provided almost equivalent separation between AMD and controls but recovery was achieved within 20 minutes
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Flicker Sensitivity in Normal Aging-Monocular Tests of Retinal Function at Photopic and Mesopic Light Levels
Purpose: Aging can affect many aspects of visual performance. In general, the effects become more significant in those older than 40 to 50 years, with increased intersubject variability and stronger dependence on ambient illumination. This study aimed to establish how healthy aging of the retina affects the detection of 15-Hz flicker under photopic and mesopic lighting.
Methods: We investigated 71 participants aged 20 to 75 years. Thresholds were measured for detection of 15-Hz flicker at the fovea (0°) and at an eccentricity of 4° in each of the four quadrants. The background luminance ranged from 0.6 to 60 cd/m2 and pupil size was measured continuously. Participants were excluded if they had signs/history of ocular disease, substantial interocular differences in flicker thresholds, or were unable to detect 100% flicker modulation in the high mesopic range.
Results: Mesopic and photopic flicker thresholds were used to calculate an index, the health of the retina index, to determine the limits of flicker sensitivity in healthy aging. Log flicker thresholds changed bilinearly with age; they remained stable until 40 to 50 years, with a linear decline with increasing age. This bilinear pattern of the change in flicker thresholds with age is consistent across photopic and mesopic light levels.
Conclusions: The health of the retina index captures the lowest threshold, usually obtained under photopic conditions, as well as the loss of flicker sensitivity with decreasing light level. The established limits of healthy aging may benefit from future studies in patients with ocular hypertension and/or glaucoma that are known to experience loss of flicker sensitivity
Do preserved foods increase prostate cancer risk?
Preserved foods have been found in some studies to be associated with increased cancer risks. The possible relationship between preserved foods and prostate cancer was investigated in a case–control study in southeast China during 2001–2002 covering 130 histologically confirmed cases and 274 inpatient controls without malignant disease. The total amount of preserved food consumed was positively associated with cancer risk, the adjusted odds ratio being 7.05 (95% CI: 3.12–15.90) for the highest relative to the lowest quartile of intake. In particular, the consumption of pickled vegetables, fermented soy products, salted fish and preserved meats was associated with a significant increase in prostate cancer risk, all with a significant dose–response relationship
Cosmic-Ray Spectra in Interstellar Space
At energies below ~300 MeV/nuc our knowledge of cosmic-ray spectra outside the heliosphere is obscured by the energy loss that cosmic rays experience during transport through the heliosphere into the inner solar system. This paper compares measurements of secondary electron-capture isotope abundances and cosmic-ray spectra from ACE with a simple model of interstellar propagation and solar modulation in order to place limits on the range of interstellar spectra that are compatible with both sets of data
Maternal lifestyle and nutritional status in relation to pregnancy and infant health outcomes in Western China: Protocol for a prospective cohort study
No commercial use is permitted unless otherwise expressly granted. Introduction Improving the health and nutrition of women and children is a priority for Western China, where the economy is less developed. Due to the dynamic nature of lifestyle, modern food habits and nutrition, there is a need to update our limited knowledge and understanding of maternal lifestyle and nutritional status and their impact on pregnancy and infant health outcomes. While breast milk is the preferred feeding option, infant formula use is widespread in China. It is thus necessary to examine the effects of formula consumption on growth and morbidity. Methods and analysis This is an ongoing prospective cohort study started in 2015 in Chengdu, Sichuan Province. A sample of 1901 pregnant women at 15-20 weeks of gestation were recruited from four maternal and child health hospitals and are followed prospectively to 12 months post partum. Detailed information on maternal lifestyle and nutritional status, obstetric complications, pregnancy outcomes, infant feeding practices, illnesses of the mother and infant and growth trajectory is collected through personal interviews, anthropometric measures and medical records and local health management system records retrieval. Multilevel mixed regression models, adjusted for clustering, will be applied to investigate the association between various exposure variables of interest and the longitudinal outcomes, taking into account the correlated data structure and the nesting of observations. Kaplan-Meier test and Cox regression analysis will be used to analyse the time-to-event data. Ethics and dissemination Ethical approval has been obtained from the ethics committee of West China School of Public Health, Sichuan University and the Human Research Ethics Committee of Curtin University. Results will be presented at national and international conferences and published in peer-reviewed journals
On the Low Energy Decrease in Galactic Cosmic Ray Secondary/Primary Ratios
Galactic cosmic ray (GCR) secondary/primary ratios such as B/C and (Sc+Ti+V)/Fe are commonly used to determine the mean amount of interstellar material through which cosmic rays travel before escaping from the Galaxy (Λ_(esc)). These ratios are observed to be energy-dependent, with a relative maximum at ~1 GeV/nucleon, implying a corresponding peak in Λ_(esc). The decrease in Λ_(esc) at energies above 1 GeV/nucleon is commonly taken to indicate that higher energy cosmic rays escape more easily from the Galaxy. The decrease in Λ_(esc) at energies <1 GeV/nuc is more controversial; suggested possibilities include the effects of a galactic wind or the effects of distributed acceleration of cosmic rays as they pass through the interstellar medium. We consider two possible explanations for the low energy decrease in Λ_(esc) and attempt to fit the combined, high-resolution measurements of secondary/primary ratios from ~0.1 to 35 GeV/nuc made with the CRIS instrument on ACE and the C2 experiment on HEAO-3. The first possibility, which hypothesizes an additional, local component of low-energy cosmic rays that has passed through very little material, is found to have difficulty simultaneously accounting for the abundance of both B and the Fe-secondaries. The second possibility, suggested by Soutoul and Ptuskin, involves a new form for Λ_(esc) motivated by their diffusion-convection model of cosmic rays in the Galaxy. Their suggested form for Λ_(esc)(E) is found to provide an excellent fit to the combined ACE and HEAO data sets
UHCR: A Cosmic Ray Mission to Study Nuclei in the Charge Range From 20 ≤Z ≤100
A definitive study of the elemental abundances of nuclei over the charge range of 20 ≤ Z ≤ 100 requires a satellite mission capable of obtaining high statistics and excellent charge resolution over the full charge range. Such a mission, utilizing an electronic instrument which is an evolution of the HEA0-3 Heavy Nuclei Experiment, is described here
The Phosphorus/Sulfur Abundance Ratio as a Test of Galactic Cosmic-Ray Source Models
Galactic cosmic-ray (GCR) elemental abundances display a fractionation compared to solar-system values that appears ordered by atomic properties such as the first ionization potential (FIP) or condensation temperature (volatility). Determining which parameter controls the observed fractionation is crucial to distinguish between GCR origin models. The Cosmic-Ray Isotope Spectrometer (CRIS) instrument on board NASA's Advanced Composition Explorer (ACE) spacecraft can measure the abundances of several elements that break the general correlation between FIP and volatility (e.g., Na, P, K, Cu, Zn, Ga, and Ge). Phosphorus is a particularly interesting case as it is a refractory (high condensation temperature) element with a FIP value nearly identical to that of its semi-volatile neighbor, sulfur. Using a leaky-box galactic propagation model we find that the P/S and Na/Mg ratios in the GCR source favor volatility as the controlling parameter
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