Cataract is a pathology associated to the loss of the normal lens transparency, and its progression can result in a total loss of vision. The gold standard diagnostic method consists on qualitative observation through a slit lamp coupled to a microscope. This method has two limitations: incipient cata- ract may not be detected and the cataract hardness is subjectively evaluated. It can result on a late diagnosis and/or on surgical complications when phacoemulsification surgery (the most common therapeutic approach) is con- ducted. On this study we present a new technology for objective cataract char- acterization, based on ultrasounds. The Eye Scan Ultrasound System (ESUS) allows the characterization of cataract type, severity and hardness based on fea- tures extracted from A-scan signals, working at a nominal frequency of 20 MHz. A total of 27 features were extracted and analyzed through automatic classification algorithms. Preclinical and clinical prototypes of the ESUS have been implemented. From data collected on the preclinical phase, the system precision, sensitivity and specificity values were 99.7%, with a relative absolute error of 0.4%. Clinical phase is in progress.