Sánchez Brea, LuisaBarreira, NoeliaMosquera González, AntonioEvans, KatharinePena Verdeal, Hugo2017-10-212017-10-212016María Luisa Sánchez Brea, Noelia Barreira Rodríguez, Antonio Mosquera González, Katharine Evans, and Hugo Pena-Verdeal, “Defining the Optimal Region of Interest for Hyperemia Grading in the Bulbar Conjunctiva,” Computational and Mathematical Methods in Medicine, vol. 2016, Article ID 3695014, 9 pages, 2016. doi:10.1155/2016/36950141748-670Xhttp://hdl.handle.net/10347/15958Conjunctival hyperemia or conjunctival redness is a symptom that can be associated with a broad group of ocular diseases. Its levels of severity are represented by standard photographic charts that are visually compared with the patient’s eye. This way, the hyperemia diagnosis becomes a nonrepeatable task that depends on the experience of the grader. To solve this problem, we have proposed a computer-aided methodology that comprises three main stages: the segmentation of the conjunctiva, the extraction of features in this region based on colour and the presence of blood vessels, and, finally, the transformation of these features into grading scale values by means of regression techniques. However, the conjunctival segmentation can be slightly inaccurate mainly due to illumination issues. In this work, we analyse the relevance of different features with respect to their location within the conjunctiva in order to delimit a reliable region of interest for the grading. The results show that the automatic procedure behaves like an expert using only a limited region of interest within the conjunctivaengCopyright © 2016 María Luisa Sánchez Brea et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedjournal article10.1155/2016/36950141748-6718open access