The Clinical Measurement Ontology (CMO), Measurement Methods Ontology (MMO), and Experimental Condition Ontology (XCO) are currently being developed at the Rat Genome Database. For more information about these vocabularies please see Shimoyama et al. Three ontologies to define phenotype measurement data. Front Genet. 2012;3:87. Epub 2012 May 28 or contact us (http://rgd.mcw.edu/contact/index.shtml).
A measurement of the chronological age, that is, the length of time since birth, of the individual when the symptoms of cataract first appeared, or when an official diagnosis of cataract was first determined. A cataract is an opacity of the crystalline lens of the eye or its capsule.