Diabetic retinopathy is a leading cause of vision impairment and blindness. We systematically reviewed studies published from Jan 1, 1980, to Jan 7, 2018, assessed the methodological quality, and ...described variations in incidence of diabetic retinopathy by region with a focus on population-based studies that were conducted after 2000 (n=8, including two unpublished studies). Of these eight studies, five were from Asia, and one each from the North America, Caribbean, and sub-Saharan Africa. The annual incidence of diabetic retinopathy ranged from 2·2% to 12·7% and progression from 3·4% to 12·3%. Progression to proliferative diabetic retinopathy was higher in individuals with mild disease compared with those with no disease at baseline. Our Review suggests that more high-quality population-based studies capturing data on the incidence and progression of diabetic retinopathy with stratification by age and sex are needed to consolidate the evidence base. Our data is useful for conceptualisation and development of major public health strategies such as screening programmes for diabetic retinopathy.
To examine subfoveal choroidal thickness (SFCT) in patients with diabetes mellitus and patients with diabetic retinopathy.
Population-based, cross-sectional study.
The population-based Beijing Eye ...Study 2011 included 3468 individuals with a mean age of 64.6 ± 9.8 years (range, 50-93 years).
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.
Subfoveal choroidal thickness.
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.
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.
The author(s) have no proprietary or commercial interest in any materials discussed in this article.
To determine associations between dyslipidemia and ocular diseases, the population-based Beijing Eye Study 2006 examined 3251 subjects (age≥45 years) who underwent a detailed ophthalmic examination ...and biochemical blood analysis. Dyslipidemia was defined as any of the following: hypercholesterolemia (total cholesterol concentration≥5.72 mmol/L (220 mg/dL)) or hypertriglyceridemia (triglyceride concentration≥1.70 mmol/L (150 mg/dL)) or low high-density lipoprotein-cholesterol (HDL-C concentration≤0.91 mmol/L (35 mg/dL)). Biochemical blood examinations were available for 2945 (90.6%) subjects. After adjustment for age, gender, habitation region, body mass index, self reported income, blood glucose concentration, diastolic blood pressure and smoking, dyslipidemia was significantly associated with higher intraocular pressure (P<0.001) and beta zone of parapapillary atrophy (P = 0.03). Dyslipidemia was not significantly associated with the prevalence of glaucoma (P = 0.99), retinal vein occlusions (P = 0.92), diabetic retinopathy (P = 0.49),presence of retinal vascular abnormalities such as focal or general arteriolar narrowing, age-related macular degeneration(P = 0.27), nuclear cataract (P = 0.14), cortical cataract (P = 0.93), and subcapsular cataract (P = 0.67). The results make one conclude that, controlled for systemic and socioeconomic parameters, dyslipidemia was not associated with common ophthalmic disorders including glaucoma and age-related macular degeneration.
To determine the prevalence and progression of myopic retinopathy in Chinese adults.
Population-based cross-sectional study.
The Beijing Eye Study 2001 included 4439 subjects of 5324 individuals who ...were invited to participate (response rate, 83.4%); the eligibility criterion was an age of 40+ years. The study was repeated in 2006, with 3251 subjects (73.2%) participating.
The participants underwent a detailed eye examination, including fundus photography. Myopic retinopathy was defined by posterior staphylomata, lacquer cracks, Fuchs' spot of the macula, and myopic chorioretinal atrophy at the posterior pole. Parapapillary atrophy was assessed separately.
Prevalence of myopic retinopathy and its change during a follow-up of 5 years.
After exclusion of pseudophakic or aphakic eyes, and eyes without assessable fundus photographs, 4319 subjects (97.3%) were included in the present study. Myopic retinopathy was present in 198 eyes (2.3%+/-0.2%; 95% confidence interval CI, 2.0-2.6) of 132 participants (3.1%). Myopic retinopathy was significantly associated with higher age (P<0.001), worse best-corrected visual acuity (P<0.001), deeper anterior chamber (P = 0.04), larger optic disc (P<0.001), less age-related macular degeneration (P = 0.02; odds ratio OR 0.90), and greater prevalence of open-angle glaucoma (P<0.001; OR 4.42). Myopic retinopathy was not associated significantly (P>0.20) with body height and weight, gender, rural versus urban region of residence, level of education, intraocular pressure, or central corneal thickness. The prevalence of myopic retinopathy increased significantly (P<0.001) with increasing myopic refractive error, from 3.8% in eyes with a myopic refractive error of < -4.0 diopters to 89.6% in eyes with a myopic refractive error of at least -10.0 diopters. At the 5-year follow-up examination, enlargement of the chorioretinal atrophy at the posterior fundus was observed in 9% of the eyes.
Myopic retinopathy was present in 3.1% of subjects aged 40+ years who resided in the Greater Beijing area. Myopic retinopathy was associated with increased age, worse best-corrected visual acuity, deeper anterior chamber, larger optic disc, less age-related macular degeneration, and higher prevalence of open-angle glaucoma.
To estimate prevalence and number of people visually impaired or blind due to cataract.
Based on the Global Burden of Diseases Study 2010 and ongoing literature research, we examined how many people ...were affected by moderate to severe vision impairment (MSVI; presenting visual acuity <6/18, ≥3/60) and blindness (presenting visual acuity <3/60) due to cataract.
In 2010, of overall 32.4 million blind and 191 million vision impaired, 10.8 million people were blind and 35.1 million were visually impaired due to cataract. Cataract caused worldwide 33.4% of all blindness in 2010, and 18.4% of all MSVI. These figures were lower in the high-income regions (<15%) and higher (>40%) in South and Southeast Asia and Oceania. From 1990 to 2010, the number of blind or visually impaired due to cataract decreased by 11.4% and by 20.2%, respectively; the age-standardized global prevalence of cataract-related blindness and MSVI reduced by 46% and 50%, respectively, and the worldwide crude prevalence of cataract-related blindness and MSVI reduced by 32% and 39%, respectively. The percentage of global blindness and MSVI caused by cataract decreased from 38.6% to 33.4%, and from 25.6% to 18.4%, respectively. This decrease took place in almost all world regions, except East Sub-Saharan Africa.
In 2010, one in three blind people was blind due to cataract, and one of six visually impaired people was visually impaired due to cataract. Despite major improvements in terms of reduction of prevalence, cataract remains a major public health problem.
To evaluate prevalence and associated factors for myopia in high school students in Beijing.
Grade 10 and 11 high school students were randomly selected from nine randomly selected districts of ...Beijing. The students underwent non-cylcoplegic auto-refractometry and an interview.
Out of 4798 eligible students, 4677 (93.4%) students (mean age:16.9±0.7years;range:16-18 years) participated. Mean refractive error of right eyes and left eyes was -2.78±2.29 diopters and -2.59±2.50 diopters, respectively. Prevalence of myopia (defined as ≤ -1.00 diopters in the worse eye) was 80.7% (95% Confidence Interval (CI): 79.6-81.8%). Out of 3773 students with myopia, 1525 (40.4%) wore glasses daily. In multiple logistic regression analysis, a higher prevalence of myopia was associated with female sex (odds ratio (OR) = 1.31;95%CI:1.11-1.55), Han ethnicity (OR = 1.64;95%CI:1.28-2.11), attending key schools (OR = 1.48;95%CI:1.24,1.77), higher family income (OR = 1.37;95%CI:1.09-1.71), longer time spent for near work (OR = 1.43;95%CI:1.06-1.93), shorter near work distance (OR = 1.87;95%CI:1.55-2.26), lower frequency of active rest during studying (OR = 1.40;95%CI:1.16-1.70), and parental myopia (OR = 2.28;95%CI:1.80-2.87). The interaction between distance from near work and time spent for near work was statistically (P = 0.03) significant. In multiple logistic regression analysis, higher prevalence of high myopia (≤-6.0 diopters) was associated with studying in key schools (OR = 1.38;95%CI:1.05,1.81), lower frequency of active rest during studying (OR = 1.40;95%CI:1.09,1.79), and a higher number of myopic parents (OR = 2.66;95%CI:2.08,3.40).
A prevalence of about 80% for myopia and a prevalence of about 10% for high myopia in students aged 16 to 18 years and attending classes of grade 10 and 11 in a Chinese metropolitan region is another example of the high prevalence of moderate and high myopia in metropolitan areas of China. With this young myopic generation getting older, myopia as cause for visual impairment and blindness may further increase in importance. Future studies may address whether active rests during studying with looking into the distance are preventive against myopia development or progression.
To examine whether the scleral cross sectional area and estimated scleral volume are associated with a longer axial length in human eyes.
Histologic anterior-posterior sections running through the ...pupil and the optic nerve head were examined. Using a light microscope, we measured the thickness of the sclera at the limbus, ora serrata, equator, midpoint between equator and posterior pole (MPEPP), peripapillary region and posterior pole. Additionally we determined the length and the cross section area of the sclera.
The histomorphometric study included 214 human globes of 214 subjects (mean age: 62.5±13.9 years) (147 eyes enucleated due to malignant choroidal melanoma or due to other non-glaucomatous reasons; 67 eyes enucleated due to secondary angle-closure glaucoma). Mean axial length was 25.1±1.8 mm (median: 24.0 mm; range: 20-35 mm). Scleral thickness measurements decreased with increasing axial length for values taken at the equator (P = 0.008; correlation coefficient r = -0.18), MPEPP (P<0.001;r:-0.47), optic nerve head border (P<0.001;r = -0.47) and posterior pole (P<0.001;r = -0.54). Scleral cross section area decreased significantly with increasing axial lengths for the regions at or behind the equator (P = 0.002;r = -0.21), at or behind the MPEPP (P = 0.001;r = -0.25), and at or behind the optic nerve head border (P = 0.001;r = -0.24). Scleral volume measurements were not significantly associated with axial length.
Despite an associated increase in surface area, eyes with longer axial length do not have an increase in scleral volume. It may point against a scleral volume enlargement to play a role in the process of axial elongation.
To determine the effect of 1% cyclopentolate on the refractive status of children aged 4 to 18 years.
Using a random cluster sampling in a cross-sectional school-based study design, children with an ...age of 4-18 years were selected from kindergardens, primary schools, junior and senior high schools in a rural county and a city. Auto-refractometry was performed before and after inducing cycloplegia which was achieved by 1% cyclopentolate eye drops.
Out of 6364 eligible children, data of 5999 (94.3%) children were included in the statistical analysis. Mean age was 10.0±3.3 years (range: 4-18 years). Mean difference between cycloplegic and non-cycloplegic refractive error (DIFF) was 0.78±0.79D (median: 0.50D; range: -1.00D to +10.75D). In univariate analysis, DIFF decreased significantly with older age (P<0.001;correlation coefficient r:-0.24), more hyperopic non-cycloplegic refractive error (P<0.001;r = 0.13) and more hyperopic cycloplegic refractive error (P<0.001;r = 0.49). In multivariate analysis, higher DIFF was associated with higher cycloplegic refractive error (P<0.001; standardized regression coefficient beta:0.50; regression coefficient B: 0.19; 95% confidence interval (CI): 0.18, 0.20), followed by lower intraocular pressure (P<0.001; beta: -0.06; B: -0.02; 95%CI: -0.03, -0.01), rural region of habitation (P = 0.001; beta: -0.04; B: -0.07; 95%CI: -0.11, -0.03), and, to a minor degree, with age (P = 0.006; beta: 0.04; B: 0.009; 95%CI: 0.003, 0.016). 66.4% of all eyes with non-cycloplegic myopia (≤-0.50D) remained myopic after cycloplegia while the remaining 33.6% of eyes became emmetropic (18.0%) or hyperopic (15.7%) under cycloplegia. Prevalence of emmetropia decreased from 37.5% before cycloplegia to 19.8% after cycloplegia while the remaining eyes became hyperopic under cycloplegia.
The error committed by using non-cycloplegic versus cycloplegic refractometry in children with mid to dark-brown iris color decreased with older age, and in parallel manner, with more myopic cycloplegic refractive error. Non-cycloplegic refractometric measures lead to a misclassification of refractive error in a significant proportion of children.
To assess axial elongation-associated characteristics in Bruch's membrane opening (BMO) as the inner optic nerve head lamella.
Participants of the population-based Beijing Eye Study without glaucoma ...underwent optical coherence tomography for measurement of the BMO size and shape.
The study included 365 individuals (mean age, 61.0 ± 8.7 years; range, 50-88 years; axial length, 24.45 ± 1.99 mm; range, 21.32-30.88 mm). Larger horizontal (mean:1.62 ± 0.28 mm) and vertical (mean: 1.74 ± 0.27 mm) BMO diameters were linearly associated with longer axial length beyond an axial length of 26.0 mm (horizontal diameter: P < 0.001; standardized regression coefficient β: 0.66; nonstandardized regression coefficient B: 0.22; 95% confidence interval (CI): 0.16, 0.27; vertical diameter: P < 0.001; β: 40; B: 0.12; 95% CI: 0.06, 0.18). In multivariable analysis, wider largest gamma zone was associated with larger intrapapillary Bruch's membrane (BM) overhanging on the side opposite to the largest gamma zone (P = 0.006; β: 0.14; B: 0.35; 95% CI: 0.10, 0.60) and with longer horizontal BMO diameter (P < 0.001; β: 0.46; B: 0.59; 95% CI: 0.46, 0.73). The widest BM overhanging location (superior to nasal) was inversely correlated with the widest gamma zone location (inferior to temporal). Within the axial length group of ≥28.0 mm, eyes with macular BM defects had a less markedly increased BMO than those without macular BM defects (2.27 ± 0.18 vs. 2.71 ± 0.41 mm; P = 0.019). The difference between horizontal BMO diameter minus horizontal gamma zone width decreased (P < 0.001) with longer axial length.
Beyond 26.0 mm of axial length, horizontal and vertical BMO diameter increased by 0.21 mm (95% CI: 0.16, 0.27) and 0.12 mm (95% CI: 0.06, 0.18), respectively, for each millimeter of axial elongation. Gamma zone may develop due to an axial elongation-associated BMO enlargement (β: 0.46) and, to a minor degree, a BMO shift in direction to the macula (β: 0.14). A large gamma zone may be protective against myopic macular BM defects.
To assess associations among outdoor activity, ocular biometric parameters, and myopia among grade 1 and grade 4 primary students in Beijing.
School-based, cross-sectional study.
A total of 382 grade ...1 and 299 grade 4 children participated in the study.
The children underwent a comprehensive eye examination, including ocular biometry by optical low-coherence reflectometry and noncycloplegic refractometry. Parents and children participated in a detailed interview, including questions on time spent indoors and outdoors.
Factors associated with myopia.
The study included 681 children, with 382 (56.1%) students from grade 1 (mean age, 6.3 ± 0.5 years; range, 5-8 years) and 299 students from grade 4 (mean age, 9.4 ± 0.7 years; range, 8-13 years); 370 students (54.3%) lived in the urban region. The mean daily time spent outdoors was 1.6 ± 0.8 hours (range, 0.5-5.1 hours). In multivariate analysis, axial length was significantly associated with older age (P<0.001; standardized β coefficient, 0.28), taller body height (P = 0.001; β, 0.18), maternal myopia (P = 0.03; β, 0.09), and urban region of habitation (P<0.001; β, -0.21), or alternatively to the region of habitation, with less time spent outdoors (P = 0.001; β, -0.16) and more time spent indoors studying (P = 0.02; β, 0.10). The axial length-to-corneal curvature radius ratio was associated with older age, urban region of habitation, maternal and paternal myopia, and paternal level of education. Presence of myopia (defined as refractive error ≤-1 diopters in the right eye) was associated with older age (P<0.001; odds ratio OR, 1.45; 95% confidence interval CI, 1.24-1.69), maternal myopia (P<0.001; OR, 2.99; 95% CI, 1.94-5.35), and urban region of habitation (P<0.001; OR, 0.17; 95% CI, 0.11-0.26), or alternatively to the region of habitation, with less time spent outdoors (P<0.001; OR, 0.32; 95% CI, 0.21-0.48) and more time spent indoors studying (P<0.001; OR, 1.38; 95% CI, 1.09-1.75).
Less outdoor activity, more indoor studying, older age, maternal myopia, and urban region of habitation were associated with longer ocular axial length and myopia in grade 1 and grade 4 primary school children in Greater Beijing. Remaining outdoors more (e.g., during school) may reduce the high prevalence of myopia in the young generation in Beijing.
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