Amblyopia is the most common cause of unilateral visual impairment in children and requires long-term treatment. This study aimed to quantify the impact of pandemic control measures on amblyopia ...management.
This was a retrospective cohort study of data from a large amblyopia management database at a major tertiary eye care centre in China.
Outpatients with amblyopia who visited the hospital from 1 June 2019, through 28 February 2022.
The primary outcome was the number of first and follow-up in-person visits to the hospital for amblyopia treatment. Secondary outcomes included the time interval between consecutive visits and improvement of vision (visual acuity, contrast sensitivity and stereopsis). Patient records were grouped into prepandemic and during pandemic periods.
A total of 10 060 face-to-face visits for 5361 patients (median age 6.7 years, IQR 5.4, 8.9) that spanned two lockdown periods were included in the analysis, of which 28% were follow-up visits. Pandemic control measures caused a sharp decline in the number of outpatient visits (3% and 30% of prepandemic levels in the months directly after the start of the first (2020) and second (2021) periods of pandemic control measures, respectively). However, these drops were followed by pronounced rebounds in visits that exceeded prepandemic levels by 51.1% and 108.5%, respectively. The interval between consecutive visits increased significantly during the pandemic from a median (IQR) of 120 (112, 127) days in 2019 to 197 (179, 224) in 2020 (p<0.001) and 189 (182, 221) in 2021 (p<0.001). There were no significant differences in the improvement of visual function or treatment compliance between the prepandemic and postpandemic groups.
The number of amblyopia patient hospital visits spiked well above prepandemic levels following lockdown periods. This pattern of patient behaviour can inform planning for amblyopia treatment services during and after public health-related disruptions.
In this paper, most of the existing Hashing methods is mapping the hand extracted features to binary code, and designing the loss function with the label of images. However, hand-crafted features and ...inadequacy considering all the loss of the network will reduce the retrieval accuracy. Supervised hashing method improves the similarity between sample and hash code by training data and labels of image. In this paper, we propose a novel deep hashing method which combines the objective function with pairwise label which is produced by the Hamming distance between the label binary vector of images, quantization error and the loss of hashing code between the balanced value as loss function to train network. The experimental results show that the proposed method is more accurate than most of current restoration methods.
To prepare alpha-calcium sulfate hemihydrate (alpha-HH) from flue gas desulfurization (FGD) byproduct under atmospheric pressure, the dehydration of FGD gypsum in a concentrated Ca and Mg chlorides ...solution medium at 95 deg C was investigated, and the effects of K+ ions were focused on. The crystal water content variation, material phases, and morphological characteristics of the dehydration products were examined and compared. The solubilities of alpha-HH in the mixed salt solutions with different K+ ion concentrations were also determined. It was found that with low concentration of K+ ions in the mixed salt solution (i.e. 0.001-0.035 M), the dehydration rate was enhanced, while with higher K+ ion concentration (i.e. 0.087-0.263 M), this process was retarded. alpha-HH was the dehydration product when K+ ion concentration was at appropriate level, while anhydrite (AH) occurred when K+ ion concentration was above 0.173 M. K+ ions were assumed to behave as a capping agent to control the morphology of the alpha-HH, resulting in crystals of lower aspect ratio. FGD gypsum can be successfully transformed into alpha-HH in concentrated Ca and Mg chloride solution under mild conditions, and K+ ions play an important role in the process.
Photocatalytic CO2 reduction to produce high value-added carbon-based fuel has been proposed as a promising approach to mitigate global warming issues. However, the conversion efficiency and product ...selectivity are still low due to the sluggish dynamics of transfer processes involved in proton-assisted multi-electron reactions. Lowering the formation energy barriers of intermediate products is an effective method to enhance the selectivity and productivity of final products. In this study, we aim to regulate the surface electronic structure of Bi2WO6 by doping surface chlorine atoms to achieve effective photocatalytic CO2 reduction. Surface Cl atoms can enhance the absorption ability of light, affect its energy band structure and promote charge separation. Combined with DFT calculations, it is revealed that surface Cl atoms can not only change the surface charge distribution which affects the competitive adsorption of H2O and CO2, but also lower the formation energy barrier of intermediate products to generate more intermediate ∗COOH, thus facilitating CO production. Overall, this study demonstrates a promising surface halogenation strategy to enhance the photocatalytic CO2 reduction activity of a layered structure Bi-based catalyst.
Purpose
Compare peripheral contrast sensitivity functions (CSF) between myopes and emmetropes to reveal potential myogenic risks during emmetropization.
Materials and methods
This observational, ...cross-sectional, non-consecutive case study included data from 19 myopes (23.42 ± 4.03 years old) and 12 emmetropes (22.93 ± 2.91 years old) who underwent central and peripheral quick CSF (qCSF) measurements. Summary CSF metrics including the cut-off spatial frequency (cut-off SF), area under log CSF (AULCSF), low-, intermediate-, and high-spatial-frequency AULCSFs (l-, i-, and h-SF AULCSFs), and log CS at 19 SFs in the fovea and 15 peripheral locations (superior, inferior, temporal, and nasal quadrants at 6, 12, 18, and 24° eccentricities, excluding the physiological scotoma at 18°) were analyzed with 3-way and 4-way between-subjects analysis of variance (ANOVA) (α = 0.05).
Results
Three-way ANOVA showed that myopes had significantly increased AULCSF at 6° (mean difference, 0.08; 95% CI, 0.02–0.13;
P
= 0.007) and 12° (mean difference, 0.09; 95% CI, 0.03–0.14;
P
= 0.003). Log CS at all 19 SFs were higher in the myopia group compared to the normal group (mean differencesuperior, 0.02; 95% CI, 0.01–0.20;
P
= 0.02 and mean differenceinferior, 0.11; 95% CI, 0.02–0.21;
P
= 0.01) at 12°. The h-SF AULCSF at 6° (mean differenceinferior, 1.27; 95% CI, 0.32–2.22;
P
= 0.009) and i-SF AULCSF at 12° (mean differencesuperior, 5.31; 95% CI, 4.35–6.27;
P
< 0.001; mean differenceinferior, 1.14; 95% CI, 0.19–2.10;
P
= 0.02) were higher in myopia vs. normal group.
Conclusion
We found myopia increased contrast sensitivity in superior and inferior visual field locations at 6° parafoveal and 12° perifoveal regions of the retina. The observation of increased contrast sensitivities within the macula visual field in myopia might provide important insights for myopia control during emmetropization.
It is widely accepted that the last eukaryotic common ancestor and early eukaryotes were intron-rich and intron loss dominated subsequent evolution, thus the presence of only very few introns in some ...modern eukaryotes must be the consequence of massive loss. But it is striking that few eukaryotes were found to have completely lost introns. Despite extensive research, the causes of massive intron losses remain elusive. Actually the reverse question -- how the few introns can be retained under the evolutionary selection pressure of intron loss -- is equally significant but was rarely studied, except that it was conjectured that the essential functions of some introns prevent their loss. The situation that extremely few (eight) spliceosome-mediated cis-spliced introns present in the relatively simple genome of Giardia lamblia provides an excellent opportunity to explore this question.
Our investigation found three types of distribution patterns of the few introns in the intron-containing genes: ancient intron in ancient gene, later-evolved intron in ancient gene, and later-evolved intron in later-evolved gene, which can reflect to some extent the dynamic evolution of introns in Giardia. Without finding any special features or functional importance of these introns responsible for their retention, we noticed and experimentally verified that some intron-containing genes form sense-antisense gene pairs with transcribable genes on their complementary strands, and that the introns just reside in the overlapping regions.
In Giardia's evolution, despite constant evolutionary selection pressure of intron loss, intron gain can still occur in both ancient and later-evolved genes, but only a few introns are retained; at least the evolutionary retention of some of the introns might not be due to the functional constraint of the introns themselves but the causes outside of introns, such as the constraints imposed by other genomic functional elements overlapping with the introns. These findings can not only provide some clues to find new genomic functional elements -- in the areas overlapping with introns, but suggest that "functional constraint" of introns may not be necessarily directly associated with intron loss and gain, and that the real functions are probably still outside of our current knowledge.
This article was reviewed by Mikhail Gelfand, Michael Gray, and Igor Rogozin.
Previous studies have demonstrated that orientation-specific deprivation in early life can lead to neural deficits of spatial vision in certain space, and can even result in meridional amblyopia ...(MA). Individuals with astigmatism are the optimal and natural models for exploring this asymmetric development of spatial vision in the human visual system. This study aims to assess the contrast sensitivity function (CSF) and EEG signals along two principal meridians in participants with regular astigmatism when being optimal optical corrected. Twelve participants with astigmatism (AST group, 20 eyes) and thirteen participants with (MA group, 19 eyes) were recruited in the current study. CSFs and spatial sweep visual evoked potentials (sVEP) were measured with vertical and horizontal sinewave gratings along two principal meridians monocularly. Area under log CSF (AULCSF), spatial frequency threshold corresponding to 80% contrast gratings (SF threshold at 80% ctr), and CSF acuity were calculated from CSF test. In addition, sVEP amplitudes and thresholds were calculated with the recursive least square method. Participants with astigmatism exhibited marked vertical-horizontal resolution disparities even after they were corrected with optimal optical corrections. CSF tests showed that AULCSF along weak meridian (measured with horizontal gratings) was lower than that along strong meridian (measured with vertical gratings) in both groups. Significant meridional disparity of CSF acuity was also found in both groups. In addition, the MA group showed larger meridional disparity compared to the AST group. Spatial sVEP thresholds also supported the existence of marked meridional disparity. Our results suggest that meridian-specific partial deprivation in early life might lead to monocularly asymmetric development of spatial vision in the human visual system. In terms of application, we tested the feasibility and reliability of adopting psychophysical and EEG scalings to investigate the asymmetric development of spatial vision related to astigmatism. These paradigms are potentially applicable to reduce and even eliminate the meridional disparity in the primary visual cortex by adopting perceptual learning or other vision-related interventions.
Contrast sensitivity (CS) is important when assessing functional vision. However, current techniques for assessing CS are not suitable for young children or non-verbal individuals because they ...require reliable, subjective perceptual reports. This study explored the feasibility of applying eye tracking technology to quantify CS as a first step toward developing a testing paradigm that will not rely on observers’ behavioral or language abilities. Using a within-subject design, 27 healthy young adults completed CS measures for three spatial frequencies with best-corrected vision and lens-induced optical blur. Monocular CS was estimated using a five-alternative, forced-choice grating detection task. Thresholds were measured using eye movement responses and conventional key-press responses. CS measured using eye movements compared well with results obtained using key-press responses Pearson’s
r
best–corrected
= 0.966,
P
< 0.001. Good test–retest variability was evident for the eye-movement-based measures (Pearson’s
r
= 0.916,
P
< 0.001) with a coefficient of repeatability of 0.377 log CS across different days. This study provides a proof of concept that eye tracking can be used to automatically record eye gaze positions and accurately quantify human spatial vision. Future work will update this paradigm by incorporating the preferential looking technique into the eye tracking methods, optimizing the CS sampling algorithm and adapting the methodology to broaden its use on infants and non-verbal individuals.
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