Population-based survey of prevalence, causes, and risk factors for blindness and visual impairment in an aging Chinese metropolitan population.

AIM: To assess the prevalence, causes, and risk factors for blindness and visual impairment among elderly (≥60 years of age) Chinese people in a metropolitan area of Shanghai, China. METHODS: Random cluster sampling was conducted to identify participants among residents ≥60 years of age living in the Xietu Block, Xuhui District, Shanghai, China. Presenting visual acuity (PVA) and best-corrected visual acuity (BCVA) were checked by the Early Treatment Diabetic Retinopathy Study (ETDRS) visual chart. All eligible participants underwent a comprehensive eye examination. Blindness and visual impairment were defined according to World Health Organization (WHO) criteria. RESULTS: A total of 4190 persons (1688 men and 2502 women) participated in the study, and the response rate was 91.1%. Based on PVA, the prevalence of blindness was 1.1% and that of visual impairment was 7.6%. Based on BCVA, the prevalence of blindness and visual impairment decreased to 0.9% and 3.9%, respectively. Older (≥80 years of age) women, with low educational levels and smoking habits, exhibited a significantly greater chance for blindness and visual impairment than did those with high educational levels and no smoking habits (P<0.05). Based on PVA and BCVA, the main causes of blindness were cataract, myopic maculopathy, and age-related macular degeneration (AMD). CONCLUSION: Our findings help to identify the population in need of intervention, to highlight the need for additional eye healthcare services in urban China.

[Prevalence of blindness and moderate and severe visual impairment among adults aged 50 years or above in Qidong City of Jiangsu Province: the China Nine-Province Survey].

OBJECTIVE: To estimate the prevalence of blindness and low vision among older adults aged > or = 50 years in Qidong City of Jiangsu Province, China, in 2006. METHODS: Cluster sampling was used in randomly selecting 5662 individuals aged > or = 50 years from September to December 2006 in 16 clusters in Qidong City. The survey was preceded by a pilot study where operational methods were refined and quality assurance evaluation was carried out. All participants were enumerated through village registers followed door-to-door visits. Eligible individuals were invited to receive visual acuity measurement and eye examination. Statistical analyses were performed using Stata/SE Statistical Software, release 9.0. Chi-square test was used to investigate the association of age, gender and education with presenting and best corrected visual acuity. RESULTS: Five thousands six hundreds and sixty-two individuals were recruited, the response rate was 90.80%. Based on the criteria of World Health Organization visual impairment classification in 1973,91 persons were diagnosed as blindness, 175 persons were diagnosed as moderate and severe visual impairment defined as best corrected visual acuity, the prevalence of blindness and moderate and severe visual impairment were 1.77% and 3.40% respectively. One hundred and thirteen persons were diagnosed as blindness, 354 persons were diagnosed as moderate and severe visual impairment defined as presenting visual acuity, the prevalence of blindness and moderate and severe visual impairment were 2.20% and 6.89% respectively. The prevalence of blindness and moderate and sever visual impairment was higher in aged (trend Chi2 = 825.16, P = 0.000), female (Chi2 = 19.85, P = 0.001), and illiterate persons (trend Chi2 = 329. 85, P = 0.000). The leading cause of blindness was cataract. CONCLUSIONS: Blindness and low vision are associated with older age and illiterates in Qidong City. According to presenting visual acuity, the causes leading to blindness and low vision are, in descending order, cataract, ocular fundus disease, refractive error and cornea disease.

[Prevalence and surgery status of cataract among adults aged 50 years or above in Qidong City of Jiangsu Province: the China Nine-Province Survey].

OBJECTIVE: To estimate the prevalence of cataract, the rate of cataract surgical coverage rate,and the rate of cataract-blindness social burden among older adults aged 50 years or above in Qidong City of Jiangsu Province, China, in 2006. METHODS: Cluster sampling was used in randomly selected 5662 individuals aged 50 years or above in 16 clusters in Qidong City. 5141 individuals received visual acuity and eye examination from September to December 2006. Lens and cataract operation status were evaluated by slit lamp. Multiple logistic regression analysis was employed to analyzed the prevalence of cataract, cataract surgical coverage rate, cataract blindness social burden rate and outcomes of surgery among different ages, sex and educational background. RESULTS: In 5141 individuals, 1098 cases of cataract were found, the prevalence of cataract was 21.35% among adults aged 50 or above. The prevalence of cataract was higher in the aged, female, illiterate persons (P < 0.01). In 89 eyes with cataract surgery, 25.84% and 42.70% of eyes were performed by the modern extra-capsular surgery and Phacoemulsification respectively. The rate of intraocular lens implantation was 69. 66%. Post-operative presenting and best corrected visual acuity more than 0.7 was 24.70% and 48.31% of operated eyes respectively. The main causes of the post-operated eyes with worse visual acuity were retinal disorders post-capsular opacity and glaucoma. The cataract surgical coverage rate was 37.96%, and the cataract blindness social burden rate was 2.10%. The cataract blindness social burden rate was higher in the aged persons (P < 0.01). CONCLUSIONS: Cataract is the most common and important eye disease that may lead into blindness and severe visual impairment among older adults aged 50 years or above. The cataract surgical coverage rate is not so high in Qidong City, and even lower in the aged persons. The first important task in blindness prevention still is the elimination of cataract blindness. The visual outcomes of the cataract surgery should be further improved in the future.

[Effects of three madriatics on the human ocular aberrations].

OBJECTIVE: To evaluate the effects of three common madriatics-phenylephrine, tropicamide and Mydrin-P on aberrations in human eye. METHODS: General aberrations, lower- and higher-order aberrations (HOA) were measured at the pupil diameter 4.0 mm and 7.0 mm with Allegretto Wave Analyzer on 37 eyes of 19 young volunteers whose spherical equivalence (SE) ranged from -0.25 D to -6.00 D. Four measured conditions were used for each subject. (1) Topical installation of 3 drops 5.0% phenylephrine hydrochloride. (2) Topical installation of 3 drops 0.5% tropicamide. (3) Topical installation of 3 drops Mydrin-P. (4) Topical installation of 3 drops 0.3% Tarivid, prior to aberometry measurements. The differences were analyzed on the values of the root-mean-square (RMS) of general (RMSg) and higher-order aberrations (RMSh), coefficient of defocus, astigmatism, the third aberrations, primary spherical aberration and the dominating type of HOA among three madriatics or between the madriatics and Tarivid solution respectively. RESULTS: There was no significant difference among the three madriatics in the average value of RMSg, RMSh, C3-C9 and C12 (P > 0.05). However, small but statistically significant difference was found in the disparity between any madriatic and Tarivid at the condition of 4.0 mm diameter of pupil. The disparity of 5% phenylephrine over RMSg and C4 was the smallest, and showed significant difference (P < 0.05). The third order aberration was more frequent dominating type of HOA over a 4.0 mm and 7.0 mm pupil for 4 eye drops, and C7 was the most frequent one among all the volunteers; there were 28 eyes (75.7%), 20 eyes (54.1%) which dominating type of HOA changed. CONCLUSIONS: All the three madriatics can be used to measure the higher-order aberrations, spherical aberration and coma in the young myopic persons. However, phenylephrine measurement may be the choice for lower-order aberrations.