User interface creation is becoming an increasingly important element in the development process for medical instrumentation. In many instances, mobility enables clients to move out of the hospital and into the home. Portable equipment may be carried by visiting medical staff or left in the hands of patients who are expected to monitor their own progress. This has various implications for product design. Reliability and power efficiency remain just as important as ever but, in addition, simplicity and ease of use come to the fore. This means that devices must be intuitive and appealing to the eye rather than complex and austere.