Chicken manure-derived biochar enhanced the potential of Comamonas testosteroni ZG2 to remediate Cd contaminated soil.

The combined remediation of Cd-contaminated soil using biochar and microorganisms has a good application value. In this study, the effect of chicken manure-derived biochar on CdCO3 precipitation induced by Comamonas testosteroni ZG2 was investigated. The results showed that biochar could be used as the carrier of strain ZG2, enhance the resistance of strain ZG2 to Cd, and reduce the toxicity of Cd to bacterial cells. Cd adsorbed by biochar could be induced by strain ZG2 to form CdCO3 precipitation. Strain ZG2 could also induce CdCO3 precipitation when biochar was added during precipitation formation and fermentation broth formation. The CdCO3 precipitation could enter the pores of the biochar and attach to the surface of the biochar. The single and combined effects of strain ZG2 and biochar could realize the remediation of Cd-contaminated soil to a certain extent. The overall effect was in the order of strain ZG2 with biochar > biochar > strain ZG2. The combination of strain ZG2 and biochar reduced soil available Cd by 48.2%, the aboveground biomass of pakchoi increased by 72.1%, and the aboveground Cd content decreased by 73.3%. At the same time, it promoted the growth and development of the root system and improved the microbial community structure of the rhizosphere soil. The results indicated that chicken manure-derived biochar could enhance the stability of CdCO3 precipitation induced by strain ZG2, and strain ZG2 combined with biochar could achieve a more stable remediation effect on Cd-contaminated soil.

Economic evaluation for medical artificial intelligence: accuracy vs. cost-effectiveness in a diabetic retinopathy screening case.

Artificial intelligence (AI) models have shown great accuracy in health screening. However, for real-world implementation, high accuracy may not guarantee cost-effectiveness. Improving AI's sensitivity finds more high-risk patients but may raise medical costs while increasing specificity reduces unnecessary referrals but may weaken detection capability. To evaluate the trade-off between AI model performance and the long-running cost-effectiveness, we conducted a cost-effectiveness analysis in a nationwide diabetic retinopathy (DR) screening program in China, comprising 251,535 participants with diabetes over 30 years. We tested a validated AI model in 1100 different diagnostic performances (presented as sensitivity/specificity pairs) and modeled annual screening scenarios. The status quo was defined as the scenario with the most accurate AI performance. The incremental cost-effectiveness ratio (ICER) was calculated for other scenarios against the status quo as cost-effectiveness metrics. Compared to the status quo (sensitivity/specificity: 93.3%/87.7%), six scenarios were cost-saving and seven were cost-effective. To achieve cost-saving or cost-effective, the AI model should reach a minimum sensitivity of 88.2% and specificity of 80.4%. The most cost-effective AI model exhibited higher sensitivity (96.3%) and lower specificity (80.4%) than the status quo. In settings with higher DR prevalence and willingness-to-pay levels, the AI needed higher sensitivity for optimal cost-effectiveness. Urban regions and younger patient groups also required higher sensitivity in AI-based screening. In real-world DR screening, the most accurate AI model may not be the most cost-effective. Cost-effectiveness should be independently evaluated, which is most likely to be affected by the AI's sensitivity.

Using choroidal thickness to detect myopic macular degeneration.

AIM: To explore the usage of choroidal thickness measured by swept-source optical coherence tomography (SS-OCT) to detect myopic macular degeneration (MMD) in high myopic participants. METHODS: Participants with bilateral high myopia (≤-6 diopters) were recruited from a subset of the Guangzhou Zhongshan Ophthalmic Center-Brien Holden Vision Institute High Myopia Cohort Study. SS-OCT was performed to determine the choroidal thickness, and myopic maculopathy was graded by the International Meta-Analysis for Pathologic Myopia (META-PM) Classification. Presence of MMD was defined as META-PM category 2 or above. RESULTS: A total of 568 right eyes were included for analysis. Eyes with MMD (n=106, 18.7%) were found to have older age, longer axial lengths (AL), higher myopic spherical equivalents (SE), and reduced choroidal thickness in each Early Treatment Diabetic Retinopathy Study (ETDRS) grid sector (P<0.001). The area under the receiver operating characteristic (ROC) curves (AUC) for subfoveal choroidal thickness (0.907) was greater than that of the model, including age, AL, and SE at 0.6249, 0.8208, and 0.8205, respectively. The choroidal thickness of the inner and outer nasal sectors was the most accurate indicator of MMD (AUC of 0.928 and 0.923, respectively). An outer nasal sector choroidal thickness of less than 74 µm demonstrated the highest odds of predicting MMD (OR=33.8). CONCLUSION: Choroidal thickness detects the presence of MMD with high agreement, particularly of the inner and outer nasal sectors of the posterior pole, which appears to be a biometric parameter more precise than age, AL, or SE.

Long-Term Risk and Prediction of Progression in Primary Angle Closure Suspect.

Importance: Identifying primary angle closure suspect (PACS) eyes at risk of angle closure is crucial for its management. However, the risk of progression and its prediction are still understudied in long-term longitudinal studies about PACS. Objective: To explore baseline predictors and develop prediction models for the 14-year risk of progression from PACS to primary angle closure (PAC). Design, Setting, and Participants: This cohort study involved participants from the Zhongshan Angle Closure Prevention trial who had untreated eyes with PACS. Baseline examinations included tonometry, ultrasound A-scan biometry, and anterior segment optical coherence tomography (AS-OCT) under both light and dark conditions. Primary angle closure was defined as peripheral anterior synechiae in 1 or more clock hours, intraocular pressure (IOP) greater than 24 mm Hg, or acute angle closure. Based on baseline covariates, logistic regression models were built to predict the risk of progression from PACS to PAC during 14 years of follow-up. Results: The analysis included 377 eyes from 377 patients (mean [SD] patient age at baseline, 58.28 [4.71] years; 317 females [84%]). By the 14-year follow-up visit, 93 eyes (25%) had progressed from PACS to PAC. In multivariable models, higher IOP (odds ratio [OR], 1.14 [95% CI, 1.04-1.25] per 1-mm Hg increase), shallower central anterior chamber depth (ACD; OR, 0.81 [95% CI, 0.67-0.97] per 0.1-mm increase), and shallower limbal ACD (OR, 0.96 [95% CI, 0.93-0.99] per 0.01 increase in peripheral corneal thickness) at baseline were associated with an increased 14-year risk of progression from PACS to PAC. As for AS-OCT measurements, smaller light-room trabecular-iris space area (TISA) at 500 µm from the scleral spur (OR, 0.86 [95% CI, 0.77-0.96] per 0.01-mm2 increase), smaller light-room angle recess area (ARA) at 750 µm from the scleral spur (OR, 0.93 [95% CI, 0.88-0.98] per 0.01-mm2 increase), and smaller dark-room TISA at 500 µm (OR, 0.89 [95% CI, 0.80-0.98] per 0.01-mm2 increase) at baseline were identified as predictors for the 14-year risk of progression. The prediction models based on IOP and central and limbal ACDs showed moderate performance (area under the receiver operating characteristic curve, 0.69; 95% CI, 0.63-0.75) in predicting progression from PACS to PAC, and inclusion of AS-OCT metrics did not improve the model's performance. Conclusions and Relevance: This cohort study suggests that higher IOP, shallower central and limbal ACDs, and smaller TISA at 500 µm and light-room ARA at 750 µm may serve as baseline predictors for progression to PAC in PACS eyes. Evaluating these factors can aid in customizing PACS management.

Four-Year Progression of Myopic Maculopathy in Children and Adolescents With High Myopia.

Importance: Individuals with high myopia younger than 18 years are at relatively high risk of progressively worsening myopic maculopathy. Additional studies are needed to investigate the progression of myopic maculopathy in this age group, as well as the risk factors associated with progression. Objective: To investigate the 4-year progression of myopic maculopathy in children and adolescents with high myopia, and to explore potential risk factors. Design, Setting, and Participants: This hospital-based observational study with 4-year follow-up included a total of 548 high myopic eyes (spherical power -6.00 or less diopters) of 274 participants aged 7 to 17 years. Participants underwent comprehensive ophthalmic examination at baseline and 4-year follow-up. Myopic maculopathy was accessed by the International Photographic Classification and Grading System. The data analysis was performed from August 1 to 15, 2023. Main Outcomes and Measures: The progression of myopic maculopathy progression over 4 years and associated risk factors. Results: The 4-year progression of myopic maculopathy was found in 67 of 548 eyes (12.2%) of 274 participants (138 girls [50.4%] at baseline and 4-year follow-up) with 88 lesion changes, including new signs of the tessellated fundus in 16 eyes (18.2%), diffuse atrophy in 12 eyes (13.6%), patchy atrophy in 2 eyes (2.3%), lacquer cracks in 9 eyes (10.2%), and enlargement of diffuse atrophy in 49 eyes (55.7%). By multivariable analysis, worse best-corrected visual acuity (odds ratio [OR], 6.68; 95% CI, 1.15-38.99; P = .04), longer axial length (AL) (OR, 1.73; 95% CI, 1.34-2.24; P < .001), faster AL elongation (OR, 302.83; 95% CI, 28.61-3205.64; P < .001), and more severe myopic maculopathy (diffuse atrophy; OR, 4.52; 95% CI, 1.98-10.30; P < .001 and patchy atrophy; OR, 3.82; 95% CI, 1.66-8.80; P = .002) were associated with myopic maculopathy progression. Conclusions and Relevance: In this observational study, the progression of myopic maculopathy was observed in approximately 12% of pediatric high myopes for 4 years. The major type of progression was the enlargement of diffuse atrophy. Risk factors for myopic maculopathy progression were worse best-corrected visual acuity, longer AL, faster AL elongation, and more severe myopic maculopathy. These findings support consideration of follow-up in these individuals and trying to identify those at higher risk for progression.

Axial Elongation Trajectories in Chinese Children and Adults With High Myopia.

Importance: Understanding the long-term axial elongation trajectory in high myopia is important to prevent blindness. Objective: To evaluate axial elongation trajectories and related visual outcomes in children and adults with high myopia. Design, Setting, and Participants: In this cohort study, participants in the Zhongshan Ophthalmic Centre-Brien Holden Vision Institute high myopia cohort were followed up every other year for 8 years. Participants with axial length measurements at baseline (2011 or 2012) and at least 1 follow-up visit were included. Participants were grouped according to baseline age as children and adolescents (7 to <18 years), young adults (18 to <40 years), and older adults (≥40 to 70 years). Data were analyzed from November 1, 2022, to June 1, 2023. Exposure: High myopia (spherical power ≤-6.00 diopters). Main Outcomes and Measures: Longitudinal axial elongation trajectories were identified by cluster analysis. Axial elongation rates were calculated by linear mixed-effects models. A 2-sided P < .05 was defined as statistically significant. Results: A total of 793 participants (median [range] age, 17.8 [6.8-69.7] years; 418 females [52.7%]) and 1586 eyes were included in the analyses. Mean axial elongation rates were 0.46 mm/y (95% CI, 0.44-0.48 mm/y) for children and adolescents, 0.07 mm/y (95% CI, 0.06-0.09 mm/y) for young adults, and 0.13 mm/y (95% CI, 0.07-0.19 mm/y) for older adults. Cluster analysis identified 3 axial elongation trajectories, with the stable, moderate, and rapid progression trajectories having mean axial elongation rates of 0.02 mm/y (95% CI, 0.01-0.02 mm/y), 0.12 mm/y (95% CI, 0.11-0.13 mm/y), and 0.38 mm/y (95% CI, 0.35-0.42 mm/y), respectively. At 8 years of follow-up, compared with the stable progression trajectory, the rapid progression trajectory was associated with a 6.92 times higher risk of developing pathological myopic macular degeneration (defined as diffuse or patchy chorioretinal atrophy or macular atrophy; odds ratio, 6.92 [95% CI, 1.07-44.60]; P = .04), and it was associated with a 0.032 logMAR decrease in best-corrected visual acuity (ß = 0.032 [95% CI, 0.001-0.063]; P = .04). Conclusions and Relevance: The findings of this 8-year follow-up study suggest that axial length in high myopia continues to increase from childhood to late adulthood following 3 distinct trajectories. At 8 years of follow-up, the rapid progression trajectory was associated with a higher risk of developing pathological myopic macular degeneration and poorer best-corrected visual acuity compared with the stable progression trajectory. These distinct axial elongation trajectories could prove valuable for early identification and intervention for high-risk individuals.

Longitudinal Changes in Axial Length and Spherical Equivalent in Children and Adolescents With High Myopia.

Purpose: To investigate longitudinal changes in axial length (AL) and spherical equivalent (SE) in children and adolescents with high myopia and to explore associated risk factors. Methods: This was a longitudinal, observational cohort study of highly myopic participants (aged 7-17 years) to evaluate the mean rates of change in AL and SE. Mixed effects regression models were used to explore the risk factors. Results: The sample consisted of 293 participants (mean age at the baseline, 13.63 ± 2.66 years; mean AL, 27.03 ± 1.30 mm diopters; mean SE, -8.99 ± 2.30 diopters) who were followed for 7.09 ± 1.64 years. Pathological myopia (PM) was present in 11.95% of the participants at the baseline. Over the follow-up period, the mean AL and SE progression rates were 0.13 mm/y (95% CI, 0.12-0.14) and -0.36 diopters/y (95% CI, -0.39 to -0.34). The multivariate analysis showed that the AL elongation and myopic SE progression decreased significantly after age 11 (ß = -0.080, P < 0.001; ß = 0.146, P < 0.001), increased with a greater baseline SE (ß = -0.006, P = 0.014; ß = 0.017, P = 0.005), and accelerated in children and adolescents who had PM at the baseline (ß = 0.043, P = 0.011; ß = -0.097, P = 0.025). Conclusions: A significant association was found between acceleration of AL elongation and myopic SE progression among the children and adolescents with age, especially those younger than 11 years, and the presence of PM.

Segmentation Errors and Off-Center Artifacts in SS-OCT: Insight from a Population-Based Imaging Study.

PURPOSE: To evaluate the frequency and associated factors of artifacts in swept-source optical coherence tomography (SS-OCT) imaging. METHODS: This was a population-based cross-sectional study. Individuals aged 35 years or older, residing in the Yuexiu district of Guangzhou, China, were recruited by random cluster sampling. Nearly half of the participants were randomly selected for SS-OCT imaging centered on the optic nerve head. Six types of artifacts in the peripapillary choroidal layer and retinal nerve fiber layer (RNFL) were graded and identified. Univariate and multivariate logistic regression analyses were used to investigate the association between the presence of artifacts and clinical characteristics. RESULTS: Out of the 616 eligible individuals who underwent SS-OCT imaging, 18.3% and 13.6% of subjects exhibited at least one artifact in peripapillary RNFL (pRNFL) and peripapillary choroidal thickness (pCT) measurements, respectively, with posterior segmentation error and off-center artifact ranked as the most common artifacts. The presence of artifacts was significantly associated with age (odds ratio [OR], 1.03; 95% confidence interval [CI], 1.01-1.06; p = .003), refractive error (OR, 0.80; 95% CI, 0.71-0.89; p < .001), and signal strength (OR, 0.95; 95% CI, 0.90-0.997; p = .039) in pRNFL thickness measurement. Similarly, the presence of artifacts in pCT measurement was significantly associated with age (OR, 1.05; 95% CI, 1.03-1.08; p < .001), and refractive error (OR, 0.76; 95% CI, 0.68-0.86; p < .001). CONCLUSION: Nearly one-fifth of the eyes were noted with at least one artifact in the population-scale SS-OCT study. Age was a risk factor for the presence of artifacts and should be considered in clinical settings.

Response mechanism of psychrotolerant Bacillus cereus D2 towards Ni (II) toxicity and involvement of amino acids in Ni (II) toxicity reduction.

The toxic effect of Nickel (Ni (II)) on humans and animals has been previously addressed. Owing to the important application of psychrotolerant bacteria in Ni (II) damage remediation in contamination sites at low temperatures, the response mechanism of psychrotolerant bacteria to Ni (II) toxicity must be elucidated. Therefore, the effect of Ni (II) toxicity on a psychrotolerant Bacillus cereus D2 was studied, showing a way to alleviate the Ni (II) toxicity in strain D2. The results showed that strain D2 growth was completely inhibited at a concentration of 100 mg/L of Ni (II). The main effects of Ni (II) toxicity on strain D2 were membrane damage and reactive oxygen species-dependent oxidative stress. Additionally, Ni (II) toxicity resulted in dysregulation of the cell cycle in strain D2. Furthermore, metabolomic analysis showed that the biosynthesis of amino acids and ABC transporters were significantly affected, and the relative abundance of seven important amino acids changed in a concentration-dependent manner. Addition of 20 mM or 5 mM amino acids to 100 mg/L Ni (II)-treated strain D2 restored its growth. This study provides insights into the way to alleviate the Ni (II) toxicity in strain D2, thus contributing to the development of bioremediation strategies.

Associations between narrow angle and adult anthropometry: the Liwan Eye Study.

PURPOSE: To assess the associations between narrow angle and adult anthropometry. METHODS: Chinese adults aged 50 years and older were recruited from a population-based survey in the Liwan District of Guangzhou, China. Narrow angle was defined as the posterior trabecular meshwork not visible under static gonioscopy in at least three quadrants (i.e. a circumference of at least 270°). Logistic regression models were used to examine the associations between narrow angle and anthropomorphic measures (height, weight and body mass index, BMI). RESULTS: Among the 912 participants, lower weight, shorter height, and lower BMI were significantly associated with narrower angle width (tests for trend: mean angle width in degrees vs weight p < 0.001; vs height p < 0.001; vs BMI p = 0.012). In univariate analyses, shorter height, lower weight and lower BMI were all significantly associated with greater odds of narrow angle. The crude association between height and narrow angle was largely attributable to a stronger association with age and sex. Lower BMI and weight remained significantly associated with narrow angle after adjustment for height, age, sex, axial ocular biometric measures and education. In analyses stratified by sex, the association between BMI and narrow angle was only observed in women. CONCLUSION: Lower BMI and weight were associated with significantly greater odds of narrow angle after adjusting for age, education, axial ocular biometric measures and height. The odds of narrow angle increased 7% per 1 unit decrease in BMI. This association was most evident in women.

Outcomes of cataract surgery in urban southern China: the Liwan Eye Study.

PURPOSE: The outcomes of cataract surgery have been well reported in rural China; however, the situation in the urban population remains unclear. This study assessed the outcomes of cataract surgery in urban southern China. METHODS: Data were gathered from the Liwan Eye Study, a population-based, cross-sectional study conducted in people aged 50 years or more in the Liwan District of Guangzhou. Presenting and best corrected visual acuity and a detailed eye examination were performed. For all aphakic and pseudophakic participants identified, information on the date, setting, type, and complications of cataract surgery were recorded. RESULTS: Of the 1405 participants, 62 people (90 eyes) had undergone cataract surgery. Of those, 54.4% underwent the phacoemulsification (Phaco) technique, 33.3% extracapsular cataract extraction (ECCE) with intraocular lens (IOL) implantation, and 11.1% ECCE without IOL; 1 patient had intracapsular cataract extraction (ICCE). Presenting visual acuity (PVA) was >6/18 in 56 (62.2%) eyes, <6/18 to >6/60 in 20 (22.2%) eyes, <6/60 to >3/60 in 3 (3.3%) eyes, and <3/60 in 11(12.3%) eyes. Of the 34 eyes with PVA less than 6/18, the principal causes were 26.5% retinal abnormalities, 20.6% glaucoma, 35.3% uncorrected aphakia or refractive error, and 14.5% posterior capsule opacification (PCO). CONCLUSIONS: ECCE or Phaco with IOL are the major surgical techniques used in urban southern China. More than half of the eyes with poor outcomes due to uncorrected aphakia, refractive error, or PCO are potentially treatable. This result suggests a pressing need for improved surgical training and postoperative care.

Refractive error and biometry in older Chinese adults: the Liwan eye study.

PURPOSE: To assess the prevalence of refractive error and describe the distribution of ocular biometry and its association with refraction in adult Chinese. METHODS: Random clustering sampling was used to identify adults aged > or = 50 years in Liwan District, Guangzhou. Refraction was determined by subjective refraction that achieved the best corrected vision based on monocular measurement. Ocular biometry was measured by A-mode ultrasound using a handheld applanation probe. RESULTS: Among 1405 participants in the study, data from 1269 phakic right eyes were available for analysis. The prevalence of myopia (SE < -0.5 D), hyperopia (SE > +0.5 D), and astigmatism (cylinder > 0.75 D) was 32.3% (95% confidence interval [CI], 27.8%-34.6%), 40.0% (95% CI, 37.3%-42.7%), and 48.3% (95% CI, 45.6%-51.1%), respectively. The spherical equivalent tended to become hyperopic at 60 years and shifted toward myopia at 75 years. Axial length did not change with age but was consistently shorter in women. Lens thickness increased with age and tended to be greater in women. CONCLUSIONS: The prevalence of myopia and biometric distribution in this urban Chinese cohort are similar to those observed in Singaporean Chinese but greater than in Mongolians and Europeans. Further studies are needed to clarify the role of environmental factors in the myopia rates.

Distribution and heritability of intraocular pressure in chinese children: the Guangzhou twin eye study.

PURPOSE: To assess the distribution and heritability of intraocular pressure (IOP) in Chinese children. METHODS: Twins aged 8 to 16 years were recruited from the Guangzhou Twin Registry. IOP was measured in each twin and co-twin together, with a handheld tonometer by the same operator. Zygosity was determined based on genotyping with 16 polymorphic markers in all same-sex twin pairs. Heritability was estimated with a univariate variance component model. RESULTS: Four hundred seventy-three twin pairs (309 monozygotic [MZ] and 164 dizygotic [DZ] twins) were available for data analyses. The mean IOP was 14.2 (SD 2.3) mm Hg. Neither age nor sex was correlated with IOP. Phenotypic correlation was 0.68 (95% confidence interval [CI], 0.62-0.74) in MZ twins and 0.40 (95% CI, 0.26-0.52) in DZ twins. A genetic model involving additive genetic and unique environmental effects was the best fit. Heritability was estimated as 66.5% (95% CI, 60.6%-71.6%). CONCLUSIONS: IOP is not correlated with age and sex in young children. Similar to the European population, the variation of IOP in healthy Chinese children is mainly attributable to additive genetic effects.

A two-site, population-based study of barriers to cataract surgery in rural china.

PURPOSE: China has among the lowest cataract surgical rates in Asia. This study was conducted to identify barriers to cataract surgery in rural China. METHODS: All subjects having undergone cataract surgery and persons with presenting visual acuity or=1 eye due to nonsurgically treated cataract were identified in two population-based studies in southern (Yangjiang) and northern (Handan) China. The subjects were administered a questionnaire assessing attitudes in four areas constituting potential barriers to surgery: knowledge about cataract, perceptions of local surgical quality, transportation and cost, and available resources. RESULTS: Interviews were completed on 71% to 86% of eligible subjects in both sites. Interviewed subjects did not differ significantly from nonrespondents with regard to age, sex, and presenting acuity in the better-seeing eye. A total of 214 (80.4%) nonsurgical and 131 (76.6%) surgical participants were interviewed, with a mean age of 71.8 +/- 8.0 and 73.7 +/- 7.4 years, respectively (P > 0.1). Among the nonsurgical subjects, 67.8% were blind (presenting vision, or=1 eye due to cataract, whereas among the surgical participants, 25.2% remained blind in the eye that had undergone surgical removal of the cataract. In a multivariate analysis adjusted for age, sex, and site, increased knowledge and higher estimates of the quality of surgery were associated with having had surgery, whereas cost and transportation scores were not. CONCLUSIONS: Lack of knowledge about cataract and concerns about the quality of local services appear to be the principal barriers to cataract surgery in rural China.

Heritability of optic disc and cup measured by the Heidelberg Retinal Tomography in Chinese: the Guangzhou twin eye study.

PURPOSE: To assess the heritability of disc area (DA), cup area (CA), and cup-disc area ratio (CDAR) as intermediate phenotypes for glaucoma in Chinese subjects in a classic twin study. METHODS: Twins (n = 1160) aged 7 to 15 years were identified in the Guangzhou Twin Registry. Optic disc parameters were measured with a Heidelberg Retina Tomograph (HRT; Heidelberg Engineering GmbH, Heidelberg, Germany) by the same examiner and grader. Zygosity was confirmed by genotyping with 16 polymorphic markers in all same-sex twin pairs. The DA, CA, and CDAR of the right eyes were chosen as the traits of interest in the analysis. Heritability was assessed by structural variance component genetic modeling, with Mx quantitative genetic modeling software, after adjustment for age and gender. RESULTS: Of those recruited, 1114 twins were identified in the analysis, including 355 monozygotic (MZ) and 202 dizygotic (DZ) twin pairs. The intraclass correlation coefficients were 0.79 for DA, 0.83 for CA, and 0.80 for CDAR in MZ pairs and 0.30, 0.37, and 0.35, respectively, in DZ pairs. The age- and sex-adjusted variance component model identified additive genetic and unshared environmental effects (AE model) being best fit for DA, CA, and CDAR. This best-fitting model yielded 77.3% additive genetic (95%CI: 73.0%-80.8%) and 22.7% unshared environment (95% CI: 19.2%-27.0%) for DA, 82.7% (95% CI:79.4%-85.5%) and 17.3% (95% CI: 14.5%-20.6%) for CA, 78.6% (95% CI: 74.5%-82.0%) and 21.4% (95% CI: 18.0%-25.4%) for CDAR. CONCLUSIONS: The variance of optic nerve head parameters (DA, CA, and CDAR) appears to be attributable to additive genetic and unshared environmental effects. Approximately 80% of these phenotypic variances are genetically determined.

Heritability of anterior chamber depth as an intermediate phenotype of angle-closure in Chinese: the Guangzhou Twin Eye Study.

PURPOSE: To assess the heritability of anterior chamber depth (ACD) and relative anterior chamber depth (ACD/axial length, rACD) in Chinese in a classic twin study. METHODS: Twins aged 7 to 15 years living in two local districts were recruited from the Guangzhou Twin Registry. Anterior chamber depth and axial length were measured by partial coherence laser interferometry. Zygosity in all same-sex twin pairs was confirmed by genotyping with 16 polymorphic markers. The phenotypes of the right eyes were used in analysis. Heritability was assessed by structural variance component genetic modeling. RESULTS: In total, 1126 twin participants were available for analysis, including 357 monozygotic (MZ) and 206 dizygotic (DZ) twin pairs. ACD increased with age (0.036 mm per year, P < 0.001) and 0.09 mm shallower in the girls than in the boys (P < 0.001). Age- and sex-adjusted intraclass correlation coefficients (ICCs) for ACD were 0.92 for the MZ and 0.50 for the DZ twins; those for rACD were 0.89 for the MZ and 0.52 for the DZ twins. The best-fitting model yielded 90.1% (95% CI: 88.2%-91.7%) of additive genetic and 9.9% (95% CI: 8.3%-11.8%) of unique environmental effects for ACD and 89.2% (95% CI: 87.1%-90.9%) of additive genetic and 10.8% (95% CI: 9.1%-12.9%) of unique environmental effects for rACD. CONCLUSIONS: Additive genetic effects appear to be the major contributor to the variation of ACD and rACD in Chinese population. High heritability remained even when the data were corrected for the influence of myopia.

Need and challenges of refractive correction in urban Chinese school children.

PURPOSE: Uncorrected refractive error is recognized as the principal cause of visual impairment in school-aged children. Although correction of refractive error is easy, safe, and effective, many children are without the necessary spectacles. Empiric research on barriers to refractive correction remains limited, precluding the formulation of effective remedial actions. The aims of this study were to characterize parental awareness and other barriers to spectacle use among children considered to be in need of refractive correction and to determine the proportion undercorrected for those already with spectacles. METHODS: A population-based sample of children 5 to 15 years of age was examined in Guangzhou, China. Visual acuity was measured followed by cycloplegic refraction and best-corrected vision. Parental awareness of the child's vision difficulties, spectacle use, and frequency of vision checkups were collected by questionnaire. Associations between these variables and demographic and socioeconomic characteristics were investigated with multiple logistic regression. RESULTS: Among the 4359 examined children, 919 (21.1%) were found to be in need of refractive correction. Need was defined as uncorrected visual acuity < or = 0.50 in both eyes correctable by at least two lines in the better eye. Parental awareness was apparent for 85% of cases; 74% had spectacles. Awareness of vision difficulties was associated with older child age, greater visual impairment, and higher parental education. The purchase of spectacles was associated with greater visual impairment; the child's age, gender, parental education, and family income were not significant factors. Undercorrection by two lines or more in the better eye was found in 30% of those already with spectacles; undercorrection was associated with greater visual impairment and less frequent refraction checkups. CONCLUSIONS: Half of the children in need of first-time or updated spectacles are without them, an unacceptably high proportion. Younger children with moderate visual impairment are at particular risk for uncorrected refractive error. Parental education and enhanced school-based screening programs may be necessary to address the unfilled need for refractive correction among school-aged children.