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.

Select Document: Sir George Radcliffe’s “Original of Government” (1639) and Absolutist Political Theory in Stuart Ireland

A seventeenth-century manuscript miscellany, which once belonged to Archbishop James Ussher of Armagh, contains a short treatise on the origins of government by Sir George Radcliffe. Radcliffe was legal assistant to Sir Thomas Wentworth, lord deputy of Ireland (from January 1640 earl of Strafford and lord lieutenant). The treatise insisted on the divine origin of all human political power and implied that the best form of government was absolute monarchy, in which the monarch was free of all human law and subject to divine restraint alone. It will be suggested below that the composition of this treatise can be dated to the summer of 1639. This introduction will offer an outline of Radcliffe’s education and political career, explain the genesis of his treatise on government, point out some pertinent aspects of its argument, and finally assess the document’s significance.