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

UNLABELLED: OBJECTIVE To assess the prevalence of blindness and moderate and severe visual impairment among adults aged 50 years or above in the Shunyi district of Beijing,China. METHODS: It was a population-based cross-section study. Geographically defined cluster sampling was used in 5840 randomly selected individuals aged > or = 50 years in 28 clusters in the Shunyi district from April to August 2006. 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 eight hundreds and forty individuals were recruited and 5118 persons were examined,the response rate was 87.64%. Based on the criteria of World Health Organization visual impairment classification in 1973,57 persons were diagnosed as blindness, 160 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 1.11% and 3.12% respectively. Sixty-five persons were diagnosed as blindness, 428 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 1.27% and 8. 36% respectively. The prevalence of blindness and moderate and severe visual impairment was higher in aged (trend Chi2 = 784.23, P = 0.000), female (Chi2 = 28.35, P = 0.000), and illiterate persons (trend Chi2 = 397.13, P = 0.000). Cataract was still the first leading cause of blindness and visual impairment, the retinal diseases was the second. Un-corrected refractive error also was the main cause of visual impairment. CONCLUSIONS: The prevalence of blindness and moderate and severe visual impairment has been decreasing among older adults aged 50 years or above in the Shunyi district since 1996. The first leading cause of blindness and visual impairment is still cataract.

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

OBJECTIVE: To assess the prevalence of cataract, the outcomes of cataract surgery, the rate of cataract surgical coverage, and the rate of cataract blindness social burden. METHODS: Cluster sampling was used in 5118 randomly selected individuals aged > or = 50 years in the Shunyi district of Beijing from April to August 2006. All individuals were received visual acuity and eye examination, including the evaluation of lens status and cataract surgical status by slit lamp biomicroscopy. Data bank was established by Epi-info Software. Statistical analyses were performed using Stata/SE Statistical Software, release 9.0 (Stata Corp, College Station,TX). 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 5118 individuals, 797 cases of cataract were found, the prevalence of cataract was 15.57% among adults aged 50 or above. The prevalence of cataract was higher in the aged, female, illiterate persons (P < 0.01). In 189 eyes with cataract surgery, 65.08% and 23.28% of eyes were performed by the modern extra-capsular surgery and Phacoemulsification respectively. The rate of intraocular lens implantation was 89.42%. Post-operative presenting and best corrected visual acuity more than 0.7 was 30.16% and 61.38% of operated eyes respectively. The main causes of the post-operated eyes with worse visual acuity were post-capsular opacity and refractive error. The cataract surgical coverage rate was 62.22%, and the cataract blindness social burden rate was 2.64%. The cataract surgical rate was lower and cataract blindness social burden rate was higher in the aged persons (P < 0.01). CONCLUSIONS: Cataract is the most common eye disease that may lead into blindness and severe visual impairment among older adults aged equal or more than 50 years. The cataract surgical coverage rate is high in the Shunyi district, but still is lower in the aged persons. The visual outcomes of the surgery should be further improved in the future.

[Detecting appositional angle closure by photopic and scotopic ultrasound biomicroscopy].

OBJECTIVE: To evaluate the prevalence of appositional angle closure in eyes with a shallow peripheral anterior chamber (AC) and the anatomic narrow chamber angle by photopic and scotopic ultrasonic biomicroscopy (UBM). METHODS: Prospective case series study. 379 eyes of 194 consecutive patients with the shallow peripheral AC and the anatomic narrow chamber angle, which was determined by Van Herick technique and gonioscopy, were collected from the clinic and an epidemiological study. The presence of appositional angle closure and the angle-opening distance (AOD) was determined with photopic and scotopic ultrasound UBM in eight positions. The prevalence of appositional angle closure and AOD calculated by photopic and scotopic ultrasound biomicroscopy were compared. Paired chi2 test and Wilcoxon test (SPSS 12.0) were used to determine any significant differences at P < 0.05. RESULTS: The prevalence of appositional angle closure was found at least one position in 264 eyes (69.7%) by scotopic UBM and in 99 (26.1%) eyes by photopic UBM. The prevalence of appositional angle closure was significantly higher by scotopic UBM than by photopic UBM (xhi2 = 159.148, P = 0.000 respectively), and was the highest in superior quadrant. The narrower AC was, the higher prevalence of appositional angle closure occurred. Furthermore, 98.3% of patients with peripheral AC < 1/4 corneal thickness (CT) were found to have an appositional angle closure by scotopic UBM. The AOD varied significantly among the four quadrants and was significantly narrower by scotopic UBM than by photopic UBM (Z = - 7.471, - 15.407, - 16.237, -16.782; P = 0.000). AOD in superior quadrant was narrowest with highest of the prevalence of appositional angle closure. CONCLUSIONS: The prevalence of appositional angle closure varied with the depth of AC and can be effectively detected by photopic and scotopic UBM, more preferably by scotopic UBM at the clinic and the mass screening.