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.

Impact of major age-related eye disorders on health-related quality of life assessed by EQ-5D: a systematic review and meta-analysis.

PURPOSE: This study is to quantitatively estimate the health-related quality of life (HRQOL) impact of major age-related eye diseases (AREDs) including cataract, glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy (DR) assessed by the EuroQoL Five-Dimensional Questionnaire (EQ-5D). METHODS: PubMed, Embase, Cochrane Library, and CINAHL were searched until October 20, 2022. Studies were included if they reported the EQ-5D health utility score (HUS) or visual analogue scale (VAS) score of both AREDs patients and healthy controls. The mean difference (MD) in HUS or VAS score between cases and controls and its 95% confidence interval (95%CI) were pooled using the random-effects model. We also performed sensitivity analysis using the leaving-one-out method and subgroup analyses by sample size and race. The prevalence in reporting any problems in the five EQ-5D dimensions was summarized and compared between cases and controls using the Chi-square test. RESULTS: Fifteen articles involving 30,491 participants were included in this review. Pooled estimates indicated reduced HUS in AMD patients (MD = - 0.04, 95%CI - 0.07, - 0.01; P = 0.009), DR patients (MD = - 0.03, 95%CI - 0.05, - 0.01; P = 0.01), and glaucoma patients (MD = - 0.06, 95%CI - 0.10, - 0.01; P = 0.01), compared with the controls. Significantly lower EQ-5D VAS score was also observed in cataract patients (MD = - 11.33, 95%CI - 13.47, - 9.18; P < 0.001) and DR patients (MD = - 6.41, 95%CI - 10.64, - 2.18; P = 0.003). AREDs patients reported usual activities and anxiety/depression problems more frequently than the control group. CONCLUSIONS: Our findings confirmed the HRQOL impairment caused by major AREDs including AMD, cataract, DR, and glaucoma. High-quality studies with large sample sizes are warranted to further verify our results.

Association between pets and dry eye symptoms: A Chinese national-based study.

BACKGROUND: Pet-derived allergens are another source of indoor air pollution which could affect human health. However, the association between pet ownership and the risk of dry eye symptoms (DES) remains to be elucidated. METHODS: We conducted a nationwide cross-sectional survey among Chinese residents aged over 12 years from June 20, 2022 to August 31, 2022. The Ocular Surface Disease Index-6 (OSDI-6) questionnaire was utilized to evaluate the presence of DES. Multivariable logistic regression models were used to analyze the associations between pet ownership and DES. Subgroup analyses were conducted based on sex, age, residence and affective disorders, and sensitivity analysis by excluding participants with major ocular diseases. The interactions between pet ownership and other risk factors on DES were explored in the additive scale by calculating the synergy index (SI). RESULTS: A total of 21,916 subjects replied to the questionnaire. The prevalence of DES was 43.6 % (95 % confidence interval (CI), 43.0 %-44.3 %). Pet ownership was significantly associated with increased risk of DES (Odds ratio (OR): 1.13, 95%CI: 1.05-1.21), especially among the elderly (OR: 1.28, 95%CI: 1.09-1.51) and urban residents (OR: 1.13, 95%CI: 1.04-1.24). The individual effect of allergic rhinitis on DES was 2.59 (95%CI: 1.27-5.53), while the joint effect of pets and allergic rhinitis was 5.26 (95%CI: 1.20-36.74), suggesting a synergistic interaction with a SI of 2.48 (95%CI: 0.25-24.39). Furthermore, the interaction analysis also indicated a synergistic interaction between pet ownership and low health literacy with a SI of 1.12 (95%CI: 0.66-1.87). CONCLUSION: Pet ownership was identified as a risk factor for DES. The synergistic interaction of pet ownership and allergic rhinitis suggests shared mechanisms between DES and allergic conditions.

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.

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.

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.

Sleep duration and the risk of major eye disorders: a systematic review and meta-analysis.

BACKGROUND: To assess the relationship between sleep duration and the risk of major eye disorders including myopia, glaucoma, cataract, age-related macular degeneration (AMD), and diabetic retinopathy (DR). METHODS: Databases including PubMed, Embase, Web of Science, and Cochrane library were searched for eligible publications before July 2021. Studies assessing the relationship between sleep duration and any one of the major eye disorders were identified. Pooled odds ratios (ORs) and their corresponding 95% confidence intervals (95% CIs) were estimated using random-effects models. RESULTS: We identified 21 relevant articles including 777348 participants, and 17 were cross-sectional, 3 were longitudinal, and 1 was case-control. Pooled results indicated that long sleep duration was significantly associated with the risk of DR (OR = 1.84, 95% CI 1.24, 2.73), and short sleep duration was significantly associated with the risk of cataract (OR = 1.20, 95% CI 1.05, 1.36). Besides, a significant relationship was observed between the risk of DR and long sleep duration per day (i.e., nighttime sleep plus daytime napping, OR = 1.74, 95% CI 1.23, 2.44) rather than per night (OR = 2.17, 95% CI 0.95, 4.99). The extreme of long sleep duration (i.e., >10 h per night) increased the risk of myopia (OR = 1.02, 95% CI 1.01, 1.04). CONCLUSIONS: Inappropriate sleep duration might increase the risk of major eye disorders. The findings could contribute to the growing knowledge on the possible relationship between circadian rhythms and eye disorders.

Impact of Area-Level Socioeconomic and Environmental Measures on Reduced Visual Acuity Among Children and Adolescents.

Purpose: To assess the impacts of area-level socioeconomic and environmental measures on reduced visual acuity (VA). Methods: This ecological study used the nationally representative cross-sectional data from the Chinese National Survey on Students' Constitution and Health in 2014 (CNSSCH 2014), which included 261,833 participants aged 7 to 22 years randomly selected from 30 mainland provinces in China. Area-level socioeconomic measures assessed included gross domestic product (GDP), population density, density of hospital beds, and nighttime light data measured as the mean digital number (DN) of each region; environmental factors assessed included latitude, annual sunlight duration, and park green space density. The main outcome measure was the prevalence of reduced VA in each province of Mainland China. Results: GDP (coefficient: 0.221; P < 0.001), mean DN (coefficient: 0.461; P < 0.001), latitude (coefficient: 0.093; P < 0.001), and annual sunlight duration (coefficient: 0.112; P < 0.001) were positively associated with the prevalence of reduced VA, while population density (coefficient: -0.256; P < 0.001), park green space per 10,000 people (coefficient: -0.145; P < 0.001), and number of hospital beds per 10,000 people (coefficient: -0.146; P < 0.001) were negatively associated with reduced VA prevalence. Factor analysis indicated a marginally nonsignificant positive correlation between socioeconomic factors and the prevalence of reduced VA (coefficient: 0.034; P = 0.07). Conclusions: Increased GDP and mean DN, which reflect economic development, were associated with a higher prevalence of reduced VA, while larger park green space and number of hospital beds per 10,000 people seemed to play a protective role, which could be targeted to design preventive strategies for myopia.

Reproductive Factors and the Risk of Open Angle Glaucoma in Women.

PRCIS: There was a significant inverse linear relationship between age at menopause and open angle glaucoma (OAG). Late menarche (≥13 y) and a history of 5 or more deliveries were significantly associated with an increased risk of OAG. PURPOSE: To determine the association between reproductive factors including age at menarche, age at menopause, reproductive period, parity, and the risk of OAG in women. METHODS: PubMed, Embase, Cochrane Library, and Web of Science were searched until February 9, 2022. Studies were included if they assessed the association between reproductive factors and OAG. The adjusted odds ratios (ORs) with relevant 95% CIs were extracted and pooled using fixed-effects models. Besides, we conducted dose-response analyses via the generalized least squares for trend method. RESULTS: Seven articles including 18,618 women were identified in this review. The pooled results indicated that late age at menarche (≥13 y) was significantly associated with an increased risk of OAG (OR=1.76, 95% CI: 1.28, 2.43). Early menopause (<45 y) also significantly elevated the risk of OAG (OR=1.89, 95% CI: 1.23, 2.90) in categorical meta-analyses, consistent with the inverse linear relationship between menopausal age and the risk of OAG in dose-response analyses ( P =0.002). In addition, women who had delivered at least 5 children were at significantly higher risk of OAG compared with those nulliparous (OR=2.35, 95% CI: 1.02, 5.39), and a J-shape relationship between parity and OAG was observed in dose-response analyses ( P <0.001). CONCLUSIONS: Late menarche (≥13 y), early menopause (<45 y), and a history of 5 or more parturitions are possible risk factors for OAG. Longitudinal studies are warranted to further examine the relationships between reproductive factors and the risk of OAG.

Smoking, dietary factors and major age-related eye disorders: an umbrella review of systematic reviews and meta-analyses.

BACKGROUND: There is accumulating evidence of the associations between age-related eye diseases (AREDs) and smoking or dietary factors. We aimed to provide an umbrella review of the published literature pertaining to smoking or dietary intake as risk factors for major AREDs including cataract, glaucoma, age-related macular degeneration (AMD) and diabetic retinopathy. METHODS: We searched for pertinent systematic reviews or meta-analyses in PubMed and Web of Science until 16 April 2022. We reperformed the meta-analysis of each association using random effects models. The heterogeneity and 95% prediction interval were calculated. The presence of small-study effect or excess significance bias was also assessed. RESULTS: In total, 64 associations from 25 meta-analyses and 41 associations from 10 qualitative systematic reviews were evaluated. There was convincing (class I) evidence for only one association, namely current smoking and cataract. Two factors had highly suggestive (class II) evidence, namely ever smoking associated with cataract and fish consumption associated with AMD. We also found suggestive (class III) evidence for associations between the dietary intake of omega-3 polyunsaturated fatty acid, lutein, zeaxanthin, vitamin C and the risk of cataract. CONCLUSIONS: Smoking as a risk factor for cataract was the most robust association we identified. We also identified several dietary elements associated with AREDs. Large prospective studies are warranted to further examine the associations discussed in this review. PROSPERO REGISTRATION NUMBER: CRD42022339082.