Reversal in gender valuations of cataract surgery after the implementation of free screening and low-priced high-quality surgery in a rural population of southern China.

PURPOSE: To assess the impact of community outreach and the availability of low-cost surgeries [500 Renminbi (RMB) or 65 United States dollars (US$) per surgery] on the willingness to pay for cataract surgery among male and female rural-dwelling Chinese.METHODS: Cross-sectional willingness-to-pay surveys were conducted at the initiation of a cataract outreach programme in June 2001 and then again in July 2006. Respondents underwent visual acuity testing and provided socio-demographic data.RESULTS: In 2001 and 2006, 325 and 303 subjects, respectively, were interviewed. On average the 2006 sample subjects were of similar age, more likely to be female (p < 0.01), illiterate (p < 0.01), and less likely to come from a household with annual income of less than US$789 (62% vs. 87%, p < 0.01). Familiarity with cataract surgery increased from 21.2% to 44.4% over the 5 years for male subjects (p < 0.01) and 15.8%-44.4% among females (p < 0.01). The proportion of respondents willing to pay at least 500 RMB for surgery increased from 67% to 88% (p < 0.01) among male subjects and from 50% to 91% (p < 0.01) among females.CONCLUSIONS: Five years of access to free cataract testing and low-cost surgery programmes appears to have improved the familiarity with cataract surgery and increased the willingness to pay at least 500 RMB (US$65) for it in this rural population. Elderly women are now as likely as men to be willing to pay at least 500 RMB, reversing gender differences present 5 years ago.

Automated retinal image quality assessment on the UK Biobank dataset for epidemiological studies

Morphological changes in the retinal vascular network are associated with future risk of many systemic and vascular diseases. However, uncertainty over the presence and nature of some of these associations exists. Analysis of data from large population based studies will help to resolve these uncertainties. The QUARTZ (QUantitative Analysis of Retinal vessel Topology and siZe) retinal image analysis system allows automated processing of large numbers of retinal images. However, an image quality assessment module is needed to achieve full automation. In this paper, we propose such an algorithm, which uses the segmented vessel map to determine the suitability of retinal images for use in the creation of vessel morphometric data suitable for epidemiological studies. This includes an effective 3-dimensional feature set and support vector machine classification. A random subset of 800 retinal images from UK Biobank (a large prospective study of 500,000 middle aged adults; where 68,151 underwent retinal imaging) was used to examine the performance of the image quality algorithm. The algorithm achieved a sensitivity of 95.33% and a specificity of 91.13% for the detection of inadequate images. The strong performance of this image quality algorithm will make rapid automated analysis of vascular morphometry feasible on the entire UK Biobank dataset (and other large retinal datasets), with minimal operator involvement, and at low cost.