Prevalence rates of cataract and cataract surgery in elderly Chinese people living in suburban Shanghai: the Pujiang Cataract Cohort Study.

PURPOSE: To estimate the prevalence rates of cataract and cataract surgery in suburban Shanghai, China. METHODS: This population-based, cross-sectional study was carried out in Pujiang Town, Shanghai, China, using a random cluster sampling strategy. A total of 5846 participants (11,657 eyes) aged ≥65 years were enrolled. Detailed eye examinations included presenting visual acuity (VA), best-corrected VA, non-contact tonometry, measurement of ocular parameters using IOLMaster 700, slit-lamp assessment of lens opacities using the Lens Opacities Classification System III and dilated fundus evaluation. RESULTS: Cataract was present in 57.0% of participants (53.8% of eyes). Cortical, nuclear and posterior subcapsular cataract (PSC) were found in 41.3%, 41.0% and 12.6% of participants. Among participants with any cataract, VA was <20/40 in 32.5%. According to Global Burden of Disease Study visual impairment (VI) criteria, 52.5% of participants with PSC had VI, 4.9% were considered blind (VA <20/400) and 31.9% had moderate VI (VA ≥20/400 to <20/63). This rate was significantly greater than that in participants with cortical (32.0%) or nuclear (38.0%) cataract (P<0.05). Cataract surgery was performed in 8.1% of eyes (men, 3.1%; women, 5.0%) or 10.9% of participants (men, 4.2%; women, 6.7%). CONCLUSIONS: The Pujiang Cataract Cohort Study has revealed the prevalence rates of cataract and cataract surgery among elderly individuals in suburban Shanghai, China. Although the frequency of cataract surgery has increased in China in recent decades, the high prevalence of cataract-related VI among older people suggests further attention to primary eyecare and medical awareness is necessary.

Determination of water content in municipal sludge by multiple headspace extraction gas chromatography.

This paper reports a new method for the determination of sludge water content by a multiple headspace extraction gas chromatographic (MHE-GC) method. It is based on measuring the GC signals for the water vapor in a sample vial from the first five headspace extractions, from which the water content in the sludge sample can be extrapolated according to the established calculation equation. The results show that the method has a good repeatability (the relative standard deviation is less than 1%) and accuracy. The maximum relative difference is less than 16% compared to the reference method. The present method is very simple and efficient, and suitable for rapid sample testing in related applications.

A joint ROI extraction filter for computer aided lung nodule detection.

Extraction of regions of interest plays an important rule in computer aided lung nodules detection. However, because of the complex background and structure, accurate and robust extraction of ROIs in medical image still remains a problem. Aim at this problem, a two-stage operations joint filter: Hessian-LoB, is proposed. The first stage is blobs (which being taken as candidate ROIs) detection and the second stage is ROIs extraction. In the first stage, the derivatives of a Hessian matrix at multiple scales are convolved with input images to localize blobs. Then in the second stage, Laplacian of bilateral filter (LoB) is convolved with the detected blobs to extract the final ROIs. Experiments show that the proposed filter can deal with images with noise and low brightness contrast, and is effectively in ROI extraction for lung nodule detection.