Wen Bin Wei

Subfoveal choroidal thickness: the Beijing Eye Study.

PURPOSE To study subfoveal choroidal thickness (SFCT) in adult Chinese subjects and its correlation with ocular biometric parameters, refractive error, and age. DESIGN Population-based longitudinal study. PARTICIPANTS The population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6±9.8 years (range, 50-93 years). METHODS A detailed ophthalmic examination was performed, including spectral-domain optical coherence tomography (SD-OCT) with enhanced depth imaging for measurement of SFCT. MAIN OUTCOME MEASURES Subfoveal choroidal thickness. RESULTS The SFCT measurements were available for 3233 subjects (93.2%). Mean SFCT was 253.8±107.4 μm (range, 8-854 μm). In multivariate analysis, SFCT increased with younger age (P<0.001; correlation coefficient r=4.12; beta coefficient=0.37), shorter axial length (P<0.001; r=44.7; beta coefficient=0.46), male gender (P<0.001; r=28.5; beta coefficient=-0.13), deeper anterior chamber depth (P<0.001; r=39.3; beta coefficient=0.13), thicker lens (P<0.001; r=26.8; beta coefficient=0.08), flatter cornea (P<0.001; r=46.0; beta coefficient=0.11), and better best-corrected visual acuity (BCVA) (logarithm of minimal angle of resolution; P=0.001; r=48.4; beta coefficient=0.06). In multivariate analysis, SFCT was not significantly associated with blood pressure, ocular perfusion pressure, intraocular pressure, cigarette smoking, alcohol consumption, serum concentrations of lipids and glucose, diabetes mellitus, and arterial hypertension. In the myopic refractive error range of more than -1 diopter (D), SFCT decreased by 15 μm (95% confidence interval [CI], 11.9-18.5) for every increase in myopic refractive error of 1 D, or by 32 μm (95% CI, 37.1-26.0) for every increase in axial length of 1 mm. For each year increase in age, the SFCT decreased by 4.1 μm (95% CI, 4.6-3.7) (multivariate analysis). CONCLUSIONS Subfoveal choroidal thickness with a mean of 254±107 μm in elderly subjects with a mean age of 65 years decreased with age (4 μm per year of age) and myopia (15 μm per diopter [D] of myopia). It was also associated with male gender and the ocular biometric parameters of a deeper anterior chamber and thicker lens. The association between SFCT and BCVA indicates a functional aspect of SFCT. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Prevalence of Diabetic Retinopathy in Rural China: The Handan Eye Study

PURPOSE To describe the age- and gender-specific prevalence, characteristics, and severity of diabetic retinopathy (DR) in a rural population in northern China. DESIGN A population-based cross-sectional study. PARTICIPANTS A total of 6830 Han Chinese aged 30 years and older from 13 villages of Yongnian County, Handan City, Hebei Province, China. METHODS All participants underwent a standardized interview, a comprehensive eye examination, and fasting blood glucose testing according to the American Diabetes Association diagnostic criteria (fasting plasma glucose >or=7.0 mmol/l). Retinal photographs obtained after pupil dilation were graded for the presence and severity of DR according to the modified Early Treatment Diabetic Retinopathy Study classification system. MAIN OUTCOME MEASURES Any DR, retinopathy grades, macular edema, or vision-threatening retinopathy. RESULTS Of the 6830 eligible individuals participating in the study, 5597 (81.9%) had fasting blood glucose results available. Of these, 387 participants (6.9%) were diagnosed with diabetes mellitus, including 247 subjects with new diabetes mellitus (NDM) and 140 subjects with known diabetes mellitus (KDM). For these, gradable photographs were available for 368 subjects (95.1%). The overall prevalence of DR was 43.1% (95% confidence interval, 38.1-48.4) and was higher in persons with KDM (65.2%) than NDM (33.5%). The prevalence of proliferative DR, macular edema, and vision-threatening retinopathy was 1.6%, 5.2%, and 6.3%, respectively, with 12.1% with KDM having untreated vision-threatening DR. No age- or gender-related differences were present. The prevalence of DR was strongly related to duration of disease. CONCLUSIONS Our study reports a high prevalence of DR among adults 30 years and older with diabetes in rural China. On the basis of estimates obtained from our study, we projected that in rural China, 21.1 million persons aged 30+ years have diabetes and 9.2 million have DR, including 1.3 million with vision-threatening DR. There is a pressing need for appropriate screening and management of diabetes and its complications in rural China.

Subfoveal Choroidal Thickness in Diabetes and Diabetic Retinopathy

PURPOSE To examine subfoveal choroidal thickness (SFCT) in patients with diabetes mellitus and patients with diabetic retinopathy. DESIGN Population-based, cross-sectional study. PARTICIPANTS The population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6 ± 9.8 years (range, 50-93 years). METHODS A detailed ophthalmic examination was performed including spectral-domain optical coherence tomography (OCT) with enhanced depth imaging for measurement of SFCT and fundus photography for the assessment of diabetic retinopathy. MAIN OUTCOME MEASURES Subfoveal choroidal thickness. RESULTS Fasting blood samples, fundus photographs, and choroidal OCT images were available for 2041 subjects (58.8%), with 246 subjects (12.1 ± 0.7%) fulfilling the diagnosis of diabetes mellitus and 23 subjects having diabetic retinopathy. Mean SFCT did not differ significantly between patients with diabetes mellitus and nondiabetic subjects (266 ± 108 vs. 261 ± 103 μm; P=0.43) nor between patients with diabetic retinopathy and subjects without retinopathy (249 ± 86 vs. 262 ± 104 μm; P = 0.56). After adjustment for age, sex, axial length, lens thickness, anterior chamber depth, corneal curvature radius, and best-corrected visual acuity, SFCT was associated with a higher glycosylated hemoglobin (HbA1c) value (P<0.001; regression coefficient B, 8.18; 95% confidence interval [CI], 4.02-12.3); standardized coefficient β, 0.08) or with the presence of diabetes mellitus (P = 0.001; B, 21.3; 95% CI, 9.12-33.5) but not with presence of diabetic retinopathy (P = 0.61) or stage of diabetic retinopathy (P = 0.14). As a corollary, after adjusting for age, region of habitation, body mass index, systolic and diastolic blood pressure, and level of education, diabetes mellitus was associated with a thicker SFCT (P<0.001). In contrast, neither presence of diabetic retinopathy (P = 0.61) nor stage of diabetic retinopathy (P = 0.09) were associated significantly with SFCT after adjusting for body mass index, diastolic and systolic blood pressure, and level of education and after adjusting for blood glucose concentrations, HbA1c value, diagnosis of diabetes mellitus, and systolic and diastolic blood pressure, respectively. CONCLUSIONS Patients with diabetes mellitus had a slightly, but statistically significantly, thicker subfoveal choroid, whereas presence and stage of diabetic retinopathy were not associated additionally with an abnormal SFCT. Whereas diabetes mellitus as a systemic disease leads to a slight thickening of the choroid, diabetic retinopathy as an ocular disorder was not associated with choroidal thickness abnormalities after adjusting for the presence of diabetes mellitus. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Reproducibility of subfoveal choroidal thickness measurements with enhanced depth imaging by spectral-domain optical coherence tomography.

PURPOSE To measure the interobserver reproducibility and intra-observer reproducibility of subfoveal choroidal thickness measurements performed by enhanced depth imaging of spectral-domain optical coherence tomography (EDI-OCT) in a population-based setting. METHODS The Beijing Eye Study 2011 was a population-based study performed in rural and urban regions of Greater Beijing. The study included 3468 individuals with a mean age of 64.6 ± 9.8 years (range, 50-93 years). The participants underwent EDI-OCT and the subfoveal choroidal thickness (SFCT) was measured. To examine the interobserver variability, all images were assessed by two examiners independently of each other within 2 months. To examine the intra-observer reproducibility, a smaller study sample consisting of 21 eyes of 21 healthy subjects from the Tongren Eye Center was included in the study. These latter subjects were scanned 10 times with 1 minute breaks between each examination. The SFCT was measured by the same observer within 2 weeks. The intrasession within subject SD, the coefficient of variation, and the intraclass correlation coefficient (ICC) were calculated. RESULTS EDI-OCTs were performed for 3233 subjects. Mean SFCT measured by grader one and grader two were 254.6 ± 107.3 μm and 253.8 ± 107.4 μm, respectively, with a mean difference of 3.14 ± 13.1 μm (95% confidence interval, 0.0, 24.0). Bland-Altman plot showed 1.9% (61/3233) points outside the 95% limits of agreement. For the assessment of the intra-observer reproducibility, the ICC was 1.00 (P < 0.001, and the mean coefficient of variation was 0.85% ± 1.48%). CONCLUSIONS Under routine examination conditions, SFCT measurements by EDI-OCT showed a high intra-observer reproducibility and interobserver reproducibility.

Prevalence and Associations of Epiretinal Membranes in a Rural Chinese Adult Population: The Handan Eye Study

PURPOSE To determine the prevalence and association of epiretinal membranes (ERMs), as assessed by retinal photography and optical coherence tomography (OCT), in a Chinese population. METHODS The Handan Eye Study is a population-based study of eye disease in rural Chinese aged 30+ years. Eligible residents underwent a detailed ophthalmic examination including retinal photography and Stratus OCT. ERMs were defined by a combination of retinal photographs and OCT and classified as cellophane macular reflex (CMR) or preretinal macular fibrosis (PMF) based on retinal photographs characteristics. RESULTS Of the 6830 persons examined, 6565 (96.1%) had gradable retinal photographs and/or OCT. The mean age was 51.7 +/- 11.6 years. ERMs were present in 3.4% (95% CI: 2.9%-3.8%) of participants, bilateral in 20.3% of the cases. CMR was present in 2.2% and PMF in 0.7%, and ERMs were unclassified in 0.5% (detected by OCT only). ERM prevalence was similar in women and men (3.6% vs. 3.1%), strongly associated with increasing age (P for trend < 0.001). After adjustment for age and sex, primary ERM was associated positively with myopia (OR: 1.58, 95% CI: 1.12-2.23) and inversely with current smoking (OR: 0.61, 95% CI: 0.38-0.97, versus never smoked). Best corrected visual acuity was significantly worse in eyes with primary ERMs (mean LogMAR score lower by 0.07, 95% CI: 0.05-0.10) than eyes without ERMs, after adjustment for age, sex, and lens status. CONCLUSIONS ERMs affect 3.4% of the population 30+ years of age and living in rural China. Idiopathic ERMs were associated with myopia, decreased visual acuity, and inversely associated with smoking.

Asymptomatic Polyvascular Abnormalities in Community (APAC) Study in China: Objectives, Design and Baseline Characteristics

Objective The population-based “Asymptomatic Polyvascular Abnormalities in Community (APAC) Study was designed to examine prevalence and associations of asymptomatic polyvascular abnormalities (APA) in a general population. In this report, the objectives, design and baseline data of the APAC study are described. Methods The study included 5,440 participants (40.1% women) with an age of 40+ years who were randomly selected from the population of the Kailuan Study which included 101,510 employees and retirees of the Kailuan Co. Ltd, a large coal mine industry located in Tangshan, Hebei, China. Exclusion criteria were previous cerebral stroke, transient ischemic attacks and coronary heart disease. In 2010 and 2011, information on potential cardiovascular risk factors was collected and all participants underwent transcranial Doppler sonography, measurement of the ankle brachial index, and bilateral carotid duplex sonography. In a first follow-up examination in 2012/2013, retinal photography and spectral-domain optical coherence tomography were additionally performed. In a planned long-term follow-up, data from clinical examinations and laboratory tests and the occurrence of cardiovascular or cerebrovascular events will be collected to build up a predicting model for the risk of ischemic events. Results At baseline, mean age of the participants was 55.2±11.8 years, and men showed a significantly (P<0.001) higher prevalence of arterial hypertension (55.5% vs. 36.5%) and hyperlipidemia (50.7% vs. 46.0%) and a higher blood homocysteine concentration (18.68±10.28µmol/L versus 11.69±6.40µmol/L). Conclusions The APAC is the first study to prospectively evaluate the relationship between intracranial arterial stenosis, retinal nerve fiber layer changes, retinal microvascular signs, and the eventual development of cerebrovascular or cardiovascular events.

Prevalence and risk factors for diabetic retinopathy: the Beijing Communities Diabetes Study 6.

Background To examine prevalence and associated factors of diabetic retinopathy in patients with Type 2 diabetes mellitus in urban communities of Beijing. Methods The community health care center–based study included subjects with diabetes mellitus and an age of 20 years to 80 years, who were recruited from 15 community health centers in urban Beijing. Diabetes mellitus was defined using the World Health Organization criteria. Fundus photographs were graded using the modified Airlie House classification system. Results Of 2,642 eligible patients, 2,007 (76.0%) subjects (1,199 women) with a mean age of 64.1 ± 9.0 years participated. The overall prevalence of diabetic retinopathy was 24.7 ± 1.0% (95% confidence interval [CI], 22.8–26.6). In binary logistic analysis, presence of diabetic retinopathy was associated with younger age (odds ratio [OR], 0.97; 95% CI, 0.95–0.98), longer duration of diabetes (OR, 1.10; 95% CI, 1.08–1.12), higher concentration of glycosylated hemoglobin HbA1c (OR, 1.23; 95% CI, 1.14–1.33), higher systolic blood pressure (OR, 1.01; 95% CI, 1.01–1.02), lower body mass index (OR, 0.95; 95% CI, 0.92–0.98), and elevated blood urea concentration (OR, 1.01; 95% CI, 1.00–1.01). Microalbuminuria was an additional associated factor (OR, 1.55; 95% CI, 1.16–2.08). Patients with microalbuminuria were 4.7 times more likely to have a severe or proliferating diabetic retinopathy than those without microalbuminuria. Conclusion In the urban population of Beijing, prevalence of diabetic retinopathy in diabetic patients was 25%. As in whites, increased blood pressure besides elevated plasma glucose concentrations was highly significantly associated with diabetic retinopathy in Chinese. It suggests that in Chinese as also in whites, blood pressure control beside control of plasma glucose levels is important to prevent development or progression of diabetic retinopathy.

Visual Acuity and Subfoveal Choroidal Thickness: The Beijing Eye Study

PURPOSE To examine the association between best corrected visual acuity (BCVA) and subfoveal choroidal thickness. DESIGN Population-based study. METHODS The Beijing Eye Study 2011 included 3468 subjects with ages of 50+ years. The participants underwent an ophthalmologic examination including spectral-domain optical coherence tomography with enhanced depth imaging for measurement of choroidal thickness. BCVA was measured as logarithm of the minimal angle of resolution. RESULTS Of the 3468 participants, choroidal measurements were available for 3233 (93.2%) subjects. In multivariate analysis, better BCVA was significantly associated with thicker subfoveal choroid (P < 0.001) in general and a subfoveal choroid thicker than 30 μm (P < 0.001) in particular, after adjusting for younger age (P < 0.001), higher level of education (P < 0.001), taller body stature (P < 0.001), higher body mass index (P = 0.005), absence of glaucoma (P = 0.001), absence of diabetic retinopathy (P < 0.001), absence of late-stage age-related macular degeneration (P < 0.001), and axial length shorter than 26.0 mm (P < 0.001) (correlation coefficient r:0.56). If eyes with glaucoma, diabetic retinopathy, late-stage age-related macular degeneration or myopic retinopathy were excluded, better BCVA was still significantly associated with thicker subfoveal choroid (P < 0.001) and subfoveal choroid thicker than 30 μm (P < 0.001) in multivariate analysis. In a reverse manner, thicker subfoveal choroid was associated with better BCVA (P < 0.001) after adjusting for younger age (P < 0.001), male gender (P < 0.001), longer axial length (P < 0.001), and higher corneal curvature radius (P < 0.001). CONCLUSIONS Better visual acuity is strongly associated with thicker subfoveal choroid independent of additional factors, such as age, axial length, education level, and major ocular diseases.

Subfoveal choroidal thickness and cerebrospinal fluid pressure: the Beijing Eye Study 2011.

PURPOSE The venous choroidal blood drains through the superior orbital vein into the intracranial cavernous sinus. The cerebrospinal fluid pressure (CSFP) may thus influence the choroidal venous blood pressure. Since volume and thickness of the choroid depend on its pressure, we tested the hypothesis whether the subfoveal choroidal thickness (SFCT) is associated with CSFP. METHODS The population-based Beijing Eye Study 2011 included 3468 individuals. A detailed ophthalmic examination was performed including spectral-domain optical coherence tomography (SD-OCT) with enhanced depth imaging for measurement of SFCT. The CSFP was calculated as CSFP (mm Hg) = 0.44 × Body Mass Index (kg/m(2)) + 0.16 × Diastolic Blood Pressure (mm Hg) - 0.18 × Age (years) - 1.91. RESULTS Mean calculated CSFP was 8.8 ± 3.7 mm Hg and mean SFCT was 254 ± 107 μm. In multivariate analysis, SFCT was significantly associated with higher CSFP (P = 0.009; standardized coefficient β: 0.08; regression coefficient B: 2.27) after adjusting for lower age (P < 0.001; β: -0.36; B: -3.99), shorter axial length (P < 0.001; β: -0.37; B: -35.7), lower body mass index (P = 0.02; β: -0.05; B: -1.51), and higher corneal curvature radius (P < 0.001; β: 0.10; B: 41.1). In univariate analysis, SFCT increased by 9.2 μm (95% confidence interval: 8.3, 10.1) for each mm Hg increase in CSFP. In a reverse manner, CSFP was significantly associated with thicker SFCT (P < 0.001; B: 0.007; β: 0.21), after adjusting for region of habitation (P < 0.001; B: -0.31; β: -2.32), higher levels of glucose (P = 0.02; B: 0.10; β: 0.04) and triglycerides (P < 0.001; B: 0.13; β: 0.09), higher intraocular pressure (P < 0.001; B: 0.17; β: 0.12), and thinner lens (P < 0.001; B: -2.39; β: -0.22). CONCLUSIONS Thicker subfoveal choroid was associated with higher CSFP after adjustment for age, axial length, body mass index, and corneal curvature radius. This association may explain thicker SFCT measurements in the morning than evening. It shows the importance of the CSFP for the physiology of the eye.

Macular Bruch´s Membrane Length and Axial Length. The Beijing Eye Study

Purpose To assess whether macular Bruch´s membrane gets lengthened in axial myopia. Methods Using the enhanced depth imaging mode of spectral-domain optical coherence tomography and examining a subgroup of participants of the population-based cross-sectional Beijing Eye Study, we measured the length of Bruch´s membrane (“MacBMLength”) from the fovea to the temporal edge of parapapillary gamma zone, and the distance between the fovea and the temporal optic disc border. Parapapillary gamma zone was defined as the parapapillary region without Bruch´s membrane. We additionally measured ocular biometric parameters and assessed non-ophthalmologic variables. Results Measurements of MacBMLength were performed on 322 individuals. MacBMLength (mean: 3.99±0.33 mm; range: 3.17–4.93 mm) was not significantly associated with any systemic parameter or ocular biometric parameter. Gamma zone width (mean: 0.18±0.30mm; range: 0.00–2.61mm) was associated (multivariate analysis; correlation coefficient r:0.80) with longer axial length (P<0.001; standardized correlation coefficient beta: 0.60; non-standardized correlation coefficient B:0.11; 95%CI: 0.09,0.14) and with longer fovea-optic disc border distance (P<0.001; beta:0.28; B:0.19; 95%CI:0.14,0.25), but not with MacBMLength (P = 0.42). Fovea-temporal disc border distance (mean: 4.16±0.44mm; range: 3.17–5.86mm) was associated (overall correlation coefficient: 0.68) with longer axial length (P<0.001; beta: 0.36; B: 0.10; 95%CI: 0.06, 0.13), after adjusting for flatter anterior chamber depth (P = 0.003; beta:-0.14; B:-0.14; 95%CI: -0.23,-0.05) and wider parapapillary gamma zone (P<0.001; beta:0.42; B:0.62; 95%CI:0.44,0.81). Conclusions In contrast to parapapillary gamma zone width and fovea-disc border distance, MacBMLength was not significantly associated with axial length. Axial elongation associated increase in fovea-disc distance may predominantly occur through development or elongation of parapapillary gamma zone, while macular Bruch´s membrane may mostly be independent of axial elongation.