Personality and Health-Related Quality of Life of Older Chinese Adults: Cross-Sectional Study and Moderated Mediation Model Analysis.

Background: Personality has an impact on the health-related quality of life (HRQoL) of older adults. However, the relationship and mechanisms of the 2 variables are controversial, and few studies have been conducted on older adults. Objective: The aim of this study was to explore the relationship between personality and HRQoL and the mediating and moderating roles of sleep quality and place of residence in this relationship. Methods: A total of 4123 adults 60 years and older were from the Psychology and Behavior Investigation of Chinese Residents survey. Participants were asked to complete the Big Five Inventory, the Brief version of the Pittsburgh Sleep Quality Index, and EQ-5D-5L. A backpropagation neural network was used to explore the order of factors contributing to HRQoL. Path analysis was performed to evaluate the mediation hypothesis. Results: As of August 31, 2022, we enrolled 4123 older adults 60 years and older. Neuroticism and extraversion were strong influencing factors of HRQoL (normalized importance >50%). The results of the mediation analysis suggested that neuroticism and extraversion may enhance and diminish, respectively, HRQoL (index: ß=-.262, P<.001; visual analog scale: ß=-.193, P<.001) by increasing and decreasing brief version of the Pittsburgh Sleep Quality Index scores (neuroticism: ß=.17, P<.001; extraversion: ß=-.069, P<.001). The multigroup analysis suggested a significant moderating effect of the place of residence (EQ-5D-5L index: P<.001; EQ-5D-5L visual analog scale: P<.001). No significant direct effect was observed between extraversion and EQ-5D-5L index in urban older residents (ß=.037, P=.73). Conclusions: This study sheds light on the potential mechanisms of personality and HRQoL among older Chinese adults and can help health care providers and relevant departments take reasonable measures to promote healthy aging.

Habitual Coffee, Tea, and Caffeine Consumption, Circulating Metabolites, and the Risk of Cardiometabolic Multimorbidity.

CONTEXT: Cardiometabolic multimorbidity (CM) is an increasing public health concern. Previous observational studies have suggested inverse associations between coffee, tea, and caffeine intake and risks of individual cardiometabolic diseases; however, their associations with CM and related biological markers are unknown. METHODS: This prospective study involved 172 315 (for caffeine analysis) and 188 091 (tea and coffee analysis) participants free of any cardiometabolic diseases at baseline from the UK Biobank; 168 metabolites were measured among 88 204 and 96 393 participants. CM was defined as the coexistence of at least 2 of the following conditions: type 2 diabetes, coronary heart disease, and stroke. RESULTS: Nonlinear inverse associations of coffee, tea, and caffeine intake with the risk of new-onset CM were observed. Compared with nonconsumers or consumers of less than 100 mg caffeine per day, consumers of moderate amount of coffee (3 drinks/d) or caffeine (200-300 mg/d) had the lowest risk for new-onset CM, with respective hazard ratios (95% CIs) of 0.519 (0.417-0.647) and 0.593 (0.499-0.704). Multistate models revealed that moderate coffee or caffeine intake was inversely associated with risks of almost all developmental stages of CM, including transitions from a disease-free state to single cardiometabolic diseases and subsequently to CM. A total of 80 to 97 metabolites, such as lipid components within very low-density lipoprotein, histidine, and glycoprotein acetyls, were identified to be associated with both coffee, tea, or caffeine intake and incident CM. CONCLUSION: Habitual coffee or caffeine intake, especially at a moderate level, was associated with a lower risk of new-onset CM and could play important roles in almost all transition phases of CM development. Future studies are warranted to validate the implicated metabolic biomarkers underlying the relation between coffee, tea, and caffeine intake and CM.

Distribution and Determinants of Anterior Chamber Angle and Anterior Chamber Volume in Young Chinese Adults.

PURPOSE: Current study aimed to understand the distribution and determinants of anterior chamber angle (ACA) and anterior chamber volume (ACV) in Chinese young adults, which can help fill current data gaps and aid in early detection and intervention for high-risk population of primary angle closure glaucoma. METHODS: This cross-sectional study utilized data from 2014 participants who completed questionnaire and eye examination in September 2021. ACV and ACA were measured using a Pentacam tomographer. Spherical equivalent (SE) was evaluated by autorefractor without cycloplegia. Central corneal thickness (CCT) and biomechanically corrected intraocular pressure (bIOP) were evaluated using Corvis-ST. Axial length (AL), corneal radius (CR), anterior chamber depth (ACD), and white to white were assessed using the IOL Master. RESULTS: A total of 1635 students were included in the analysis. The mean ACV and AVA were 194.74 ± 32.30 µL and 38.81 ± 4.84°, respectively. Males have a larger ACV and wider ACA than females. ACV was positively correlated with ACA (r = 0.24, p < 0.001), and the correlation was stronger for non-myopic students than for myopic students. Multivariable linear regression model showed that AL (ß = 2.41), CR (ß = -4.12), CCT (ß = -0.11), ACD (ß = 97.93), and bIOP (ß = 0.40) were associated with ACV, and CCT (ß = -0.01), CR (ß = 0.38), and ACD (ß = 7.41) were associated with ACA (all p < 0.05). Random forest model indicated that ACD was the most critical predictor of both ACV and ACA. CONCLUSIONS: This study reported the distribution and determinants of ACA and ACV. Deeper ACD was associated with larger ACV and wider ACA.

Omega-3 Polyunsaturated Fatty Acids as a Protective Factor for Myopia.

PURPOSE: Animal models suggest omega-3 polyunsaturated fatty acids (PUFAs) may protect against myopia by modulating choroidal blood perfusion, but clinical evidence is scarce and mixed. We aimed to determine the causality between omega-3 PUFAs and myopia using Mendelian randomization (MR) analysis. DESIGN: Two-sample MR analysis. METHODS: Exposures are genetically predicted 18 fatty acids (FAs) related traits. Spherical equivalent refraction (SER) and axial length were used as measurements of myopia. Genome-wide association study summary data on blood levels of 18 FAs related traits (n=115,006), refractive spherical equivalent (n=351,091), axial length (n=69,945) and choroidal thickness (n=44,823) were sourced from the UK Biobank, the Genetic Epidemiology Research on Adult Health and Aging cohort, and the Consortium for Refractive Error and Myopia Study. We used five MR models and considered results statistically significant if the Bonferroni-corrected P-value was ≤2.78 × 10-3 in at least 3 MR models. The beta represents the change in outcomes (SER in diopter; axial length in mm; choroidal thickness in standard deviation) per standard deviation unit increase in FAs levels. RESULTS: At a Bonferroni-corrected significance, higher levels of omega-3 (Beta, 0.32-0.34), omega-3/total FAs ratio (Beta, 0.31-0.44), docosahexaenoic acid (DHA) (Beta, 0.36-0.46), DHA/total FAs ratio (Beta, 0.37-0.53), PUFAs/total FAs ratio (Beta, 0.07-1.003), and degree of unsaturation (Beta, 0.28-0.44) were associated with a more positive SER, suggesting a lower risk of myopia. Similar trends were observed for axial length albeit with borderline significance (P≤0.035 in ≥2 models). Higher levels of omega-3, DHA, DHA/total FAs ratio, PUFAs/total FAs ratio, PUFAs/monounsaturated FAs ratio, and degree of unsaturation were nominally associated with thicker choroidal thickness (Beta, 0.05-0.13; P≤0.045 in ≥2 models). CONCLUSION: Our multiple MR models suggest a protective effect of omega-3 and DHA on myopia, potentially through modulation of choroidal blood perfusion. Further randomized clinical trials are needed to confirm the effectiveness and determine the optimal dose and duration.

Lower indoor spatial frequency increases the risk of myopia in children.

BACKGROUND/AIMS: Animal models have shown that the absence of high-frequency visual information can precipitate the onset of myopia, but this relationship remains unclear in humans. This study aims to explore the association between the spatial frequency content of the visual environment and myopia in children. METHODS: Images from the rooms of children and their frequently visited outdoor areas were taken by their parents and collected by the researcher through questionnaires. The spatial frequency was quantified using Matlab. Cycloplegic refraction was used to measure the spherical equivalent (SE), and IOL Master was used to measure axial length (AL) and corneal radius (CR). AL/CR ratio was calculated. RESULTS: The study included 566 children with an average age of (8.04±1.47) years, of which 270 were girls (47.7%), and the average SE was (0.70±1.21) D. Image analysis revealed that indoor spatial frequency slope was lower than that of the outdoor environment (-1.43±0.18 vs -1.11±0.23, p<0.001). There were 79 myopic individuals (14.0%). Images from indoor content of myopic children had a lower spatial frequency slope than non-myopic children (-1.47±0.16 vs 1.43±0.18, p=0.03) while there was no significant difference in outdoor spatial frequency slope. Regression analysis indicated that the indoor spatial frequency slope was positively associated with SE value (ß=0.60, p=0.02) and inversely related to myopia (OR=0.24, p<0.05). CONCLUSION: The spatial frequency of the outdoor environment is significantly higher than that of the indoor environment. Indoor spatial frequency is related to children's refractive status, with lower indoor spatial frequency being associated with a higher degree of myopia.

Establishing and Validating Refractive Error Reference Values for Myopia Prediction Among Children Aged 6-12 Years - Jiangsu Province, China, 2018-2023.

What is already known about this topic?: Previously, it has been proved that a simplified model that uses refraction error value provides a robust and efficient means of predicting myopia for non-myopic students. Intervention targeting non-myopic children with alert refraction errors (or insufficient hyperopia reserve) holds significant importance in reducing the incidence rate of myopia. What is added by this report?: This study, comprising two phases (surveillance and cohort studies), was aiming to pinpoint the precise refractive error value for the onset of myopia prediction among non-myopic children in Jiangsu Province. What are the implications for public health practice?: First, when conducting myopia screenings using pupil dilation for non-myopic populations: the cycloplegic 50th percentile refractive error emerges as a more precise predictive indicator. Second, when conducting myopia screenings without pupil dilation: this study advocates for the incorporation of axial length (AL) and corneal curvature (CC) values as supplementary indicators in screenings.

Multimorbidity patterns and the risk of falls among older adults: a community-based study in China.

BACKGROUND: Due to the high prevalence of multimorbidity and realistic health service demands for fall prevention, there is growing interest in the association between multimorbidity and falls. Our study aimed to identify multimorbidity patterns among Chinese older adults and explore the association between multimorbidity patterns and falls. METHODS: Data from 4,579 Chinese community-dwelling older adults was included in this analysis. Information regarding falls and 10 chronic conditions was collected. An exploratory factor analysis was performed to determine multimorbidity patterns. Regression models were fitted to explore the associations of individual chronic disease or multimorbidity patterns with falls. RESULTS: Among 4,579 participants, 368 (8.0%) were defined as fallers, including 92 (2.0%) frequent fallers, and multimorbidity affected 2,503 (54.7%) participants. Older adults with multimorbidity were more likely to be fallers [odds ratio (OR) = 1.3, P = 0.02] and frequent fallers (OR = 1.7, P = 0.04). Three multimorbidity patterns were identified (i.e., cardiovascular-metabolic diseases, psycho-cognitive diseases and organic diseases), and the associations between psycho-cognitive diseases/organic diseases and prevalent falls or frequent falls were found to be significant. CONCLUSIONS: The psycho-cognitive disease pattern and organic disease pattern are significantly associated with falls. Therefore, more attention should be paid to patients with psycho-cognitive diseases and timely, targeted diagnostic and treatment services should be provided in fall prevention.

The impact of 25-hydroxyvitamin D and calcium on risk of age-related macular degeneration: a Mendelian randomization study.

BACKGROUND: The relationships between 25-hydroxyvitamin D [25(OH)D] and calcium and age-related macular degeneration (AMD) are unclear. OBJECTIVES: This study aimed to investigate the causal role of 25(OH)D concentrations, calcium concentrations, and dietary supplements use of vitamin D and calcium on risk of AMD and its subtypes. METHODS: Independent genetic variants associated with 25(OH)D and calcium concentrations were used as instrumental variables in published genome-wide association studies (GWASs) of European ancestry. The bidirectional 2-sample Mendelian randomization (MR) analyses were performed using summary-level data from the UK Biobank and FinnGen datasets. Sensitivity analyses were conducted to ensure the robustness of the MR results. The meta-analyses were conducted using both fixed-effect and random-effect models to provide comprehensive and reliable estimates. RESULTS: A standard deviation increase in calcium concentrations was linked to a 14%, 17%, and 13% reduction in the likelihood of developing AMD (95% confidence interval [CI]: 0.77, 0.97), wet AMD (95% CI: 0.73, 0.95), and dry AMD (95% CI: 0.75, 1.00), respectively. No significant causal relationships were detected between genetically predicted 25(OH)D concentrations and AMD and its subtypes (all P > 0.05). The combined analyses showed that higher calcium concentrations were associated with a reduced risk of overall AMD, with an odds ratio of 0.89 (95% CI: 0.81, 0.98). CONCLUSIONS: This study provides evidence supporting the causal relationship between calcium concentrations and risk of AMD and its subtypes, which may have important implications for the prevention, monitoring, and treatment of AMD.

Reduced Health-Related Quality of Life Due to Mobile Phone Dependence in a Sample of Chinese College Students: The Mediating Role of Chronotype and Sleep Quality.

PURPOSE: Presenting a chain mediation model to investigate whether mobile phone dependence results in a reduction in health-related quality of life (HRQoL) among Chinese college students, through the mediating effect of chronotype and sleep quality. DESIGN AND SETTING: A cross-sectional survey was conducted on students from a Chinese university using a validated structured questionnaire. SAMPLE: 2014 freshmen. MEASURES: The study measured the students' level of mobile phone dependence using the Self-rating Questionnaire for Adolescent Problematic Mobile Phone Use. Chronotype and sleep quality were measured by the Chinese version of the Morningness-Eveningness Questionnaire (MEQ) and the Pittsburgh Sleep Quality Index (PSQI), respectively. HRQoL was evaluated using the five-level EuroQol five-dimensional questionnaire (EQ-5D-5L), including a descriptive system and a visual analog scale (VAS). ANALYSIS: Descriptive statistical analysis, correlation analysis, and mediation analysis. RESULTS: Mobile phone dependence had a significant negative effect on HRQoL as indicated by both the EQ-5D-5L index score and EQ-VAS score (P < .001 for both). Additionally, it was found to significantly predict chronotype (MEQ score) (ß = -.546, P < .001) and sleep quality (PSQI score) (ß = .163, P < .001). Chronotype negatively predict sleep quality (ß = -.058, P < .001), and sleep quality was a significant negative predictor of HRQoL (EQ-5D-5L index score, ß = -.008, P < .001; EQ-VAS score, ß = -1.576, P < .001). CONCLUSION: Mobile phone dependence negatively impacts students' HRQoL through chronotype and sleep quality, and there is a chain mediating effect. Students should consider making lifestyle changes to improve their HRQoL and promote health.

Association between ambient air pollution and dry eye symptoms among Chinese individuals during the COVID-19 pandemic: A national-based study.

PURPOSE: To examine the association between ambient air pollution and dry eye symptoms (DES) during the COVID-19 pandemic and explore whether air pollution had increased the risk of DES to a greater extent than other risk factors. METHODS: A nationwide cross-sectional survey was conducted from June 20, 2022 to August 31, 2022. The Ocular Surface Disease Index-6 (OSDI-6) questionnaire was used to assess the presence of DES. Logistic regression models were employed to analyze the associations between DES and air pollution variables, including air quality index (AQI), fine particulate matter (PM2.5), PM10, sulfur dioxide (SO2), carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3) and residing near industrial zones. We explored the interactions of air pollutants and other risk factors in the additive models by calculating the synergy index (SI). Standardized regression coefficients were calculated to compare the relative importance of risk factors for DES. RESULTS: A total of 21,909 participants were included in the analysis. Residing near industrial zones was significantly correlated with a higher risk of DES (Odds ratio (OR): 1.57, 95 % confidence interval (CI): 1.38-1.79). No significant associations were found between DES and air pollutants except SO2 (OR: 1.05, 95 % CI: 1.02-1.09, per standard deviation increment in SO2 concentration). The restricted cubic spline analyses revealed a linear concentration-response relationship between SO2 and DES. The interaction analyses suggested synergetic interactions of SO2 with depression and problematic internet use. Among the risk factors, depression, anxiety and problematic Internet use contributed more to the increased risk of DES. CONCLUSION: The association between ambient air pollutants and DES may have been mitigated during the pandemic due to increased time spent indoors. Despite this, our findings support the deleterious health impact of air pollutants. Future urban planning should plan industrial zones further away from residential areas.

EQ-5D-5L Population Norms for China Derived From a National Health Survey.

OBJECTIVES: To develop the EQ-5D-5L (5L) population norms for China and to assess the relationship between various factors and 5L data. METHODS: This study used data derived from the Psychology and Behavior Investigation of Chinese Residents, a national sample survey of 21 909 representative participants aged 12 years and above. Participants' health-related quality of life (HRQoL) was measured by the 5L. Their socioeconomic characteristics, behavioral factors, and health conditions were also obtained from the survey. Norm scores were generated and compared for different socioeconomic variables. Multiple linear and logistic regressions were used to assess the relationships of the 3 kinds of variables with the 5L utility, visual analog scale (VAS) scores and 5L health problems. RESULTS: The mean (SD) age of participants was 39.4 (18.9) years, and 50.0% of them were female. The mean (SD) utility and VAS scores were 0.940 (0.138) and 73.4 (21.6), respectively. Participants reported considerably more problems in anxiety/depression (26.2%) and pain/discomfort (22.2%) dimensions. The gender difference in HRQoL is attenuated. The participants older than 75 years suffered from a sharp decline in HRQoL; the participants in Shanghai and Tibet provinces reported lower utility and VAS scores and more health problems. Those who were younger, with better socioeconomic status and healthier lifestyles, and without diseases tended to report higher utility and VAS scores and fewer health problems. CONCLUSIONS: This study derived the 5L population norms for China based on a representative population sample.

Socioeconomic Burden of Pyogenic Liver Abscess Caused by Klebsiella Pneumoniae from a Teaching Hospital in East China.

Background: The prevalence of pyogenic liver abscess (PLA) is increasing worldwide. However, evaluation on its economic burden is still lack. Methods: A retrospective study that included all patients identified PLA from 2017 to 2020 was conducted. Clinical information and hospital costs were collected through the electronic medical records. We evaluated the economic burden using disability-adjusted life years (DALYs). Differences in socioeconomic burdens between Klebsiella pneumoniae-caused liver abscesses (KPLA) and non-Klebsiella pneumoniae-caused liver abscesses (non-KPLA) were compared. Results: We found 327 patients identified PLA in the study, including 146 with KPLA and 181 with non-KPLA. The demographic characteristics, median hospital stay, severity, and in-hospital mortality were similar between the two groups. The median total in-hospital cost was higher in the non-KPLA than in the KPLA group, although no statistical difference was found ($3607.2 vs $3424.6; P = 0.446). The median DALY loss was significantly higher in the KPLA than in the non-KPLA group [1.49 (0.97-2.30) vs 1.27 (0.87-1.89); P = 0.033)], and male patients presented a higher average DALY loss than female patients. KPLA had a substantially greater median indirect economic loss than the non-KPLA group [$1442.8 (915.9-17,221.5) vs $1232.5 (764.6-15,473.0); P = 0.028], and indirect economic loss exhibited a significant increase from 2017 to 2020 in patients with PLA. No differences were found in the socioeconomic burden between the two groups [$8019.6 (4200.3-21,832.1) vs $7436.4 (4023.2-19,063.9); P = 0.172]. Conclusion: The economic burden of PLA is significant, particularly in patients with KP. Patients with KPLA experienced increased DALY loss and indirect economic loss than non-KPLA. PLA must be prioritized as the indirect economic burden rises annually.

Quantifying depressive symptoms on incidence of common chronic diseases and multimorbidity patterns in middle-aged and elderly Chinese adults.

BACKGROUND: Depressive symptoms are highly prevalent and increase risks of various morbidities. However, the extent to which depressive symptoms could account for incidence of these chronic conditions, in particular multimorbidity patterns, remains to be examined and quantified. METHODS: For this cohort analysis, we included 9024-14,093 participants aged 45 years and older from the China Health and Retirement Longitudinal Study (CHARLS). Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the longitudinal associations between depressive symptoms and 13 common chronic diseases and 4 multimorbidity patterns. Population attributable fractions (PAFs) combining the information on both exposure prevalence and risk association were estimated to quantify the magnitude of the burden of these conditions attributable to depressive symptoms. RESULTS: Depressive symptoms were associated with increased risks of liver disease, stroke, heart problem, asthma, diabetes, arthritis, kidney disease, chronic lung disease, digestive disease, dyslipidemia, and memory-related disease, and the adjusted HRs (95% CIs) and PAFs (95% CIs) ranged from 1.15 (1.05-1.26) to 1.64 (1.38-1.96) and 5% (0-10%) to 17% (6-28%), respectively. In addition, individuals with depressive symptoms had elevated risks of the cardiometabolic-cancer pattern, the cerebrovascular-memory pattern, the articular-visceral organ pattern, and the respiratory pattern, with respective HRs (95% CIs) of 1.26 (1.11-1.42), 1.34 (1.07-1.69), 1.45 (1.29-1.63), and 2.01 (1.36-2.96), and respective PAFs (95% CIs) of 5% (0-10%), 8% (-4-21%), 12% (7-17%), and 20% (5-35%). CONCLUSION: Depressive symptoms contribute substantially to the burden across a broad range of chronic diseases as well as different multimorbidity patterns in middle-aged and older Chinese.

Cost-effectiveness of screening for amblyopia among kindergarten children in China.

Objective: Current cost-effectiveness analyses of amblyopia screening are mainly from western countries. It remains unclear whether it is cost-effective to implement a preschool amblyopia screening programme in China. Our study aimed to evaluate the cost-effectiveness of a hypothetical kindergarten-based amblyopia screening versus non-screening among 3-year-old children. Methods: We developed a decision tree combined with a Markov model to compare the cost and effectiveness of screening versus non-screening for 3-year-old children from a third-party payment perspective. The primary outcomes were quality-adjusted life years (QALYs) and the incremental cost-effectiveness ratio (ICER). Costs were obtained from expert opinions in different regions of China. Transition probabilities and health utilities were mainly based on published literature and open sources. Sensitivity analyses were performed to assess the impact of parameters' uncertainty on results. Results: Base-case analysis demonstrated that the ICER of screening versus non-screening was $17,466/QALY, well below the WTP threshold ($38,223/QALY) for China. One-way sensitivity analysis showed that the prevalence of amblyopia, the transition probability per year from untreated amblyopia to healthy, and the discount rate were the top three factors. The likelihood of cost-effectiveness of screening compared with non-screening was 92.56%, according to probabilistic sensitivity analysis. Scenario analysis also indicated that ICER was lower than the WTP threshold even if the time horizon was shortened or the screening was delayed to the age of 4 or 5. Conclusions: Amblyopia screening could be considered a cost-effective strategy compared to non-screening for 3-year-old children in China. Screening for children at the age of 4 or 5 may even yield better results.

Dry eye symptoms and health-related quality of life among Chinese individuals: a national-based study.

AIMS: To assess the impact of dry eye symptoms (DESs) on health-related quality of life (HRQOL) among Chinese residents. METHODS: A total of 21 916 participants were involved in this nationwide cross-sectional study. All of them completed the Ocular Surface Disease Index-6 and the five-level European Quality of Life 5-Dimensional (EQ-5D) Questionnaire to assess the severity of DES and HRQOL, respectively. Multiple linear regression models were used to explore the associations of DES with EQ-5D health utility score (HUS) and visual analogue scale (VAS) score. We used logistic regression models to assess the relationships between DES and self-reported problems in the EQ-5D dimensions. RESULTS: Overall, 43.6% of participants reported DESs. Of them, 2511 (11.5%) were with mild symptoms, 2762 (12.6%) were with moderate symptoms and 4288 (19.6%) were with severe symptoms. Both EQ-5D HUS and VAS score were significantly negatively associated with the severity of DES. The difference in HUS between patients with no symptoms and severe symptoms (0.085) was larger than the minimally clinical important difference for EQ-5D. The loss in HRQOL was greater for patients with severe DES than those just with other comorbidities. Participants with DES had a significantly higher risk of reporting problems in all five EQ-5D dimensions, especially in pain/discomfort and anxiety/depression for patients with mild or moderate symptoms and in mobility, self-care and usual activities for severe patients. CONCLUSION: Patients with more severe DES tend to have lower HRQOL. Effective interventions targeted at different HRQOL dimensions should be taken according to the severity of DES.

Corneal Biomechanical Characteristics in Myopes and Emmetropes Measured by Corvis ST: A Meta-Analysis.

PURPOSE: To comprehensively identify the corneal biomechanical differences measured by Corvis ST between different degrees of myopia and emmetropia. DESIGN: Systematic review and meta-analysis. METHODS: Electronic databases, including PubMed, Embase, and Web of Science, were systematically searched for studies comparing the corneal biomechanics among various degrees of myopes and emmetropes using Corvis ST. The weighted mean differences and 95% confidence intervals were calculated. Meta-analysis was performed in high and nonhigh myopes and in myopes and emmetropes, respectively. RESULTS: Eleven studies were included in this study. The meta-analysis among myopes and emmetropes included 1947 myopes and 621 emmetropes, and 443 high myopes and 449 nonhigh myopes were included in the meta-analysis among high and nonhigh myopia. Myopes showed the cornea with significantly longer time at the first applanation (A1t) and lower length at the second applanation (A2L) than emmetropes. High myopes showed significantly greater A1t, velocity at the second applanation (A2v), deformation amplitude at the highest concavity (HC-DA), and peak distance at the highest concavity (HC-PD) and decreased time at the second applanation (A2t) and radius of the highest concavity (HC-R). CONCLUSIONS: Corneal biomechanics is different in myopia, especially in high myopia. Compared with nonhigh myopes, the corneas of high myopes deformed slower during the first applanation, faster during the second applanation, and showed greater deformation amplitude, indicating greater elasticity and viscidity.

Distribution and determinants of corneal volume among healthy young Chinese adults: a cross-sectional study.

BACKGROUND: Several studies have previously reported the normal values of corneal volume (CV) in various populations, whereas little is known about the CV distribution in healthy young Chinese adults. Our study aimed to investigate the distribution of CV and its relationships with other ocular biometric parameters among healthy young Chinese adults. METHODS: A total of 1645 eyes from 1645 students at Dali University in Yunnan Province, China, were analyzed. Pentacam was used to measure CV. Central corneal thickness (CCT) and biomechanically corrected intraocular pressure (bIOP) were evaluated by Corvis-ST. Other biometrical parameters, including axial length (AL), keratometry, and white-to-white (WTW) distance, were measured using IOL Master. RESULTS: The mean age of the study population was 19.01 ± 0.92 years, and 68.81% of them were women. The CV was normally distributed in the whole sample, with a mean value of 61.23 ± 3.22 mm3. CV and CCT were significantly smaller in the Yi ethnic group than in the Han ethnic group (p < 0.01). CCT (coefficient: 0.085; p < 0.001) and keratometry (coefficient: 0.422; p < 0.001) were positively correlated with CV, while AL (coefficient: -0.204; p < 0.001), WTW distance (coefficient: -0.236; p < 0.001) and bIOP (coefficient: -0.06; p < 0.001) were inversely associated with CV. CONCLUSIONS: Our study provides an age-specific distribution of CV among healthy young Chinese adults. CCT, keratometry, AL, WTW distance and bIOP were important factors associated with CV.

Association of sleep traits with myopia in children and adolescents: A meta-analysis and Mendelian randomization study.

PURPOSE: The association between sleep and myopia in children and adolescents has been reported, yet it remains controversial and inconclusive. This study aimed to investigate the influence of different sleep traits on the risk of myopia using meta-analytical and Mendelian randomization (MR) techniques. METHODS: The literature search was performed in August 31, 2023 based on PubMed, Embase, Web of Science, and Cochrane library. The meta-analysis of observational studies reporting the relationship between sleep and myopia was conducted. MR analyses were carried out to assess the causal impact of genetic pre-disposition for sleep traits on myopia. RESULTS: The results of the meta-analysis indicated a significant association between the risk of myopia and both short sleep duration [odds ratio (OR) = 1.23, 95% confidence interval (CI) = 1.08-1.42, P = 0.003] and long sleep duration (OR = 0.75, 95% CI = 0.66-0.86, P < 0.001). MR analyses revealed no significant causal associations of genetically determined sleep traits with myopia, including chronotype, sleep duration, short sleep duration and long sleep duration (all P > 0.05). CONCLUSIONS: No evidence was found to support a causal relationship between sleep traits and myopia. While sleep may not independently predict the risk of myopia, the potential impact of sleep on the occurrence and development of myopia cannot be disregarded.

Corneal stress‒strain index in relation to retinal nerve fibre layer thickness among healthy young adults.

BACKGROUND/OBJECTIVES: To determine the relationship between corneal stress-strain index (SSI) and retinal nerve fibre layer (RNFL) thickness. SUBJECTS/METHODS: 1645 healthy university students from a university-based study contributed to the analysis. The RNFL thickness was measured by high-definition optical coherence tomography (HD-OCT), axial length (AL) was measured by IOL Master, and corneal biomechanics including SSI, biomechanical corrected intraocular pressure (bIOP), and central corneal thickness (CCT) were measured by Corvis ST. Multivariate linear regression was performed to evaluate the relationship between the SSI and RNFL thickness after adjusting for potential covariates. RESULTS: The mean age of the participants was 19.0 ± 0.9 years, and 1132 (68.8%) were women. Lower SSI was significantly associated with thinner RNFL thickness ( ß =8.601, 95% confidence interval [CI] 2.999-14.203, P = 0.003) after adjusting for age, CCT, bIOP, and AL. No significant association between SSI and RNFL was found in men, while the association was significant in women in the fully adjusted model. The association was significant in the nonhigh myopic group ( P for trend = 0.021) but not in the highly myopic group. Eyes with greater bIOP and lower SSI had significantly thinner RNFL thickness. CONCLUSIONS: Eyes with lower SSI had thinner RNFL thickness after adjusting for potential covariates, especially those with higher bIOP. Our findings add novel evidence of the relationship between corneal biomechanics and retinal ganglion cell damage.