Biomedical subjects

Yaxing Wang

Publications and source records attributed to Yaxing Wang.

6 recordsLinked to original sources

PubMed2006

High myopia and glaucoma susceptibility the Beijing Eye Study.

OBJECTIVE: To evaluate whether marked myopia, compared with moderate myopia and low myopia, is associated with a higher prevalence of glaucomatous optic nerve damage. DESIGN: Population-based cross-sectional study. PARTICIPANTS: Four thousand four hundred thirty-nine of 5324 subjects 40 years or older were invited to participate (response rate, 83.4%). The group was stratified according to refractive error into high myopia (myopia > -8 diopters [D]), marked myopia (<-6 to -8 D), moderate myopia (<-3 to -6 D), low myopia (<-0.5 to -3 D), emmetropia (-0.5 to + <2 D), and hyperopia (>+ 2 D) subgroups. METHODS: Morphologic assessment of optic disc monoscopic photographs. MAIN OUTCOME MEASURES: Morphologic optic disc parameters and intraocular pressure (IOP). RESULTS: For 4319 (97.3%) subjects (8484 eyes), optic disc photographs were evaluated. Prevalence of glaucomatous optic nerve atrophy as defined by the glaucomatous optic nerve head appearance did not vary significantly (P = 0.77; odds ratio [OR], 1.2; 95% confidence interval [CI], 0.38-3.81) between the highly myopic group and the group with marked myopia. In both refractive groups combined, glaucoma frequency seemed to be higher (P = 0.075; OR, 2.28; 95% CI, 0.99-5.25) higher than in the group with moderate myopia; it was significantly (P = 0.001; OR, 3.5; 95% CI, 1.71-7.25) higher than in the group with low myopia; significantly (P<0.001; OR, 7.56; 95% CI, 3.98-14.35) higher than in the group with emmetropia; and significantly (P = 0.005; OR, 4.23; 95% CI, 1.57-11.45) higher than in the group with hyperopia. Glaucoma frequency did not vary significantly between the hyperopic group and the emmetropic group (P = 0.17), the group with low myopia (P = 0.83), and the group with moderate myopia (P = 0.32). Intraocular pressure did not vary significantly (P>0.10) between any of the subgroups. Similar results were obtained for the frequency of glaucoma defined as glaucomatous optic disc appearance and visual field defects. In binary logistic regression analysis, presence of glaucoma was significantly associated with the myopic refractive error (P<0.001), age (P<0.001), and IOP (P<0.001). CONCLUSIONS: Marked to high myopia with a myopic refractive error exceeding -6 D may be a risk factor associated with glaucomatous optic neuropathy.

Adult↗

PubMed2006

Retinal vascular abnormalities in adult Chinese in rural and urban Beijing: the Beijing Eye Study.

OBJECTIVE: To assess retinal vascular abnormalities, including focal and generalized arteriolar narrowing, arteriovenous nicking, and arteriolar sheathing, in adult Chinese in rural and urban Beijing, and their associations with self-reported diagnosis of cardiovascular and cerebrovascular diseases. DESIGN: Population-based cross-sectional cohort study. PARTICIPANTS: The study included 4439 subjects out of 5324 subjects invited to participate (response rate, 83.4%) with an age of > or =40 years. It was divided into a rural part (n = 1973 [44.4%]) and an urban part (n = 2466 [55.6%]). Mean age was 56.2+/-10.6 years (range, 40-101 years). METHODS: Color optic disc photographs were morphometrically examined. One eye of each participant was randomly selected. Generalized and focal arteriolar narrowing, arteriovenous nicking (arteriovenous crossing abnormalities), and arteriolar sheathing were assessed. Self-reported histories of cardiovascular and cerebrovascular diseases and habits of smoking and alcohol drinking were obtained from questionnaires. MAIN OUTCOME MEASURES: Frequency of generalized and focal arteriolar narrowing, arteriovenous nicking, and arteriolar sheathing. RESULTS: Optic disc photographs were available for 4228 (95.2%) subjects. Focal arteriolar narrowing was found in 6.3%, arteriovenous nicking in 6.6%, arteriolar sheathing in 4.8%, and generalized narrowing in 4.3% of the subjects. Abnormalities were more common in the temporal quadrant; they were rare in the inferior nasal quadrant. Frequencies and severities of all retinal microvascular abnormalities examined increased with age (P<0.05). The microvascular abnormalities were detected more frequently in the rural population than in the urban population (P<0.05). After controlling for age, gender, area, and habit of drinking alcohol, generalized arteriolar narrowing (odds ratio [OR], 2.63; 95% confidence interval [CI], 1.64, 4.22), focal arteriolar narrowing (OR, 1.51; 95% CI, 1.00, 2.29), and arteriolar sheathing (OR, 1.71; 95% CI, 1.08, 2.71) were significantly associated with the self-reported diagnosis of arterial hypertension. The microvascular abnormalities were not significantly associated with the self-reported diagnosis of coronary heart disease or stroke. CONCLUSIONS: Retinal vascular abnormalities in adult Chinese increase with age and are more commonly found in people living in rural areas. Retinal vascular abnormalities are associated with the self-reported diagnosis of arterial hypertension, and are not related to self-reported diagnosis of coronary heart disease or previous cerebrovascular events such as stroke.

Adult↗

PubMed2006

Causes of blindness and visual impairment in urban and rural areas in Beijing: the Beijing Eye Study.

OBJECTIVE: To evaluate the causes of visual impairment and blindness in adult Chinese in an urban and rural region of Beijing, China. DESIGN: Population-based prevalence survey. PARTICIPANTS: From a rural region and an urban region of Greater Beijing, 4439 of 5324 > or=40-year-old invited subjects participated in the study (response rate, 83.4%). Using the World Health Organization (WHO) standard and the United States standard, blindness was defined as best-corrected visual acuity (BCVA) in the better-seeing eye of <20/400 and of <2/20, respectively, and visual impairment was defined as best-corrected vision of <20/60 and > or =20/400, and of <20/40 and > or =2/20, respectively. METHODS: Determination of BCVA, pneumotonometry, frequency doubling perimetry, evaluation of photographs of the fundus and lens, and clinical examination. MAIN OUTCOME MEASURE: Causes of visual impairment and blindness. RESULTS: Visual acuity measurements were available for 8816 eyes of 4409 subjects (99.3%). Using the WHO standard and the U.S. standard, 49 (1.1%) subjects and 95 (2.2%) subjects, respectively, had low vision, and 13 (0.3%) subjects and 15 (0.3%) subjects, respectively, were blind by definition. Taking the whole study population, the most frequent cause of low vision/blindness was cataract (36.7%/38.5%), followed by degenerative myopia (32.7%/7.7%), glaucoma (14.3%/7.7%), corneal opacity (6.1%/15.4%), and other optic nerve damage (2.0%/7.7%). Age-related macular degeneration (AMD) (2.0%/7.7%) and diabetic retinopathy (0%/7.7%) were responsible for a minority of cases. In subjects 40 to 49 years old, the most frequent cause of low vision and blindness was degenerative myopia. In the 50- to 59-year age group, the most frequent cause was cataract, followed by degenerative myopia. In the 60- to 69-year-old subjects and the > or =70-year group, the most frequent cause of low vision and blindness was cataract, followed by degenerative myopia and glaucoma. CONCLUSIONS: The most frequent cause of low vision and blindness in adult Chinese is cataract, followed by degenerative myopia and glaucomatous optic neuropathy, with degenerative myopia dominating in younger groups and cataract dominating in elder groups. In contrast to studies in Western countries, AMD and diabetic retinopathy appear to play a minor role as a cause of visual impairment in elderly Chinese.

Adult↗

PubMed2006

Prevalence and causes of visual field loss as determined by frequency doubling perimetry in urban and rural adult Chinese.

PURPOSE: To determine prevalence and causes of visual field loss (VFL) as determined by frequency doubling perimetry in elderly Chinese individuals. DESIGN: Population-based, cross-sectional cohort study. METHODS: The Beijing Eye Study included 4439 of 5324 subjects (83.4%) who were invited to participate with an age of 40+ years. Visual field was assessed by frequency doubling threshold perimetry. Main outcome measure was an abnormal visual field defined as at least one test location of reduced sensitivity. RESULTS: Of the 4439 people who were examined, 4350 subjects (98.0%; 8617 eyes) provided measurement data by frequency doubling perimetry. In subjects aged 40 to 49 years, the most frequent cause for VFL was degenerative myopia followed by glaucoma, other optic nerve diseases, and cataract. In the subjects aged 60 to 69 years, the most frequent cause for VFL was cataract, followed by glaucoma and degenerative myopia. In the subjects aged 70+ years, the most frequent cause for VFL was glaucoma, followed by cataract and degenerative myopia. VFL was associated significantly with age (P < .001), myopic refractive error (P < .001), rural region (P = .001), low level of education (P = .01), degree of nuclear cataract (P < .001), and intraocular pressure (P < .001). CONCLUSION: In contrast to Western countries, age-related macular degeneration and diabetic retinopathy play a minor role as a cause for VFL in China.

Adult↗

PubMed2006

Optic disk size in chronic glaucoma: the Beijing eye study.

PURPOSE: To evaluate whether eyes with chronic glaucoma have a larger or smaller optic disk than normal eyes. DESIGN: Population-based, cross-sectional cohort study. METHODS: The study included 4439 subjects out of 5324 subjects invited to participate with an age of 40+ years. Color optic disk photographs (45 degrees ) were morphometrically examined. RESULTS: After exclusion of aphakic eyes, pseudophakic eyes, and highly myopic eyes, data of 3989 subjects entered the statistical analysis. The mean optic disk area did not vary significantly (P > .05) between the nonglaucomatous group (2.61 +/- 0.50 mm(2)), eyes with glaucomatous appearance of the optic disk (2.69 +/- 0.63 mm(2)), eyes with glaucomatous optic disks and visual field defects (2.66 +/- 0.70 mm(2)), and eyes with elevated intraocular pressure (2.63 +/- 0.49 mm(2)). CONCLUSIONS: In adult Chinese, optic disk size may not markedly differ between normal eyes and eyes with chronic glaucoma.

Adult↗

PubMed2006

Frequency of optic disk hemorrhages in adult chinese in rural and urban china: the Beijing eye study.

PURPOSE: To determine the frequency of optic disk hemorrhages in the adult Chinese population. DESIGN: Population-based prevalence survey. METHODS: The study included 4439 subjects out of 5324 subjects invited to participate (response rate 83.4%) with an age of 40+ years. Mean age was 56.2 +/- 10.6 years. Color optic disk photographs (45 degrees) were morphometrically examined. RESULTS: Optic disk photographs were available for 8655 eyes of 4378/4439 (98.6%) subjects. Prevalence of disk hemorrhages was 107/8655 (1.24%; 95% confidence interval (CI): 1.00%, 1.47%) eyes. Occurrence of disk hemorrhages was significantly associated with glaucomatous optic nerve damage (P < .001; OR: 9.3; 95% CI: 5.6, 15.4) and age (P = .008; 95% CI: 1.01, 1.05). The occurrence of disk hemorrhages was not significantly associated with intraocular pressure (IOP) (P = .63; 95% CI: 0.97, 1.06), refractive error (P = .06; 5% CI: 0.87, 2.18), and visual field score (P = .81; 95% CI: 0.96, 1.03). Defining glaucoma as glaucomatous optic disk appearance, 20/107 (18.7%; 95% CI: 11.2%, 26.2%) disk hemorrhages were found in glaucomatous eyes. Out of 226 glaucomatous eyes, 20/226 (8.8%; 95%CI: 5.12%, 12.58%) eyes showed a disk hemorrhage. Hypertensive glaucoma eyes and normotensive glaucoma eyes did not vary considerably in frequency of disk hemorrhages (P = .44; OR: 1.82; 95% CI: 0.59, 5.68). CONCLUSIONS: Disk hemorrhages occur in a frequency of approximately 1.2% in adult Chinese. Major associated factors are glaucomatous optic neuropathy and age. Presence of a disk hemorrhage suggested glaucomatous optic nerve damage with a positive predictive value of approximately 20%. About 9% of glaucomatous eyes showed a disk hemorrhage at the time of examination.

Adult↗