Usability is a key aspect in medical device design because its correct application allows for the development of a product with a proper user/device interface, as well as labelling and instructions for use, where provided, that are effective in terms of readability and understanding. Usability requirements must take into account the user profile, the type of device, its principles of operation, its Intended use environment and the human factors. Therefore, the manufacturers' goals for conducting a comprehensive usability process are the patient’s safety, the development of a user-friendly product and the mitigation of foreseeable user errors.
IEC 62366-1:2015 has not yet been harmonised with the Medical Device Regulation (EU) 2017/745 (MDR), however, the MDR stated that manufacturers should take into account the “generally acknowledged state of the art,” which suggests that IEC 62366-1:2015 should be utilised in the medical device usability process.
The IEC 62366 standard is structured in two parts:
- IEC 62366-1:2015 – Application of usability engineering to Medical Devices.
- IEC/TR 62366-2:2016 – Guidance on the Application of usability to engineering to Medical Devices.
IEC 62366-1:2015 - Part 1 specifies a process for a manufacturer to analyze, specify, develop and evaluate the usability of a medical device as it relates to safety. This usability engineering (human factors engineering) process permits the manufacturer to assess and mitigate risks associated with correct use and use errors, i.e., normal use. It can be used to identify but does not assess or mitigate risks associated with abnormal use.
IEC/TR 62366-2:2016 - Part 2 is a Technical Report, that contains background information and provides guidance that addresses specific areas that experience suggests can be helpful for those implementing a usability engineering (human factors engineering) process both as defined in IEC 62366-1:2015 and as supporting goals other than safety.
What is Usability Engineering?
“Usability engineering” or “human factors engineering” is the “application of knowledge about human behaviour, abilities, limitations, and other characteristics to the design of medical devices (including software), systems and tasks to achieve adequate usability.”
The usability engineering process, therefore, is necessary to design and manufacture user-friendly medical devices and to minimize user errors during the preparation, use and maintenance of the product.
Commonly it is thought that the usability engineering process is only required for software or devices equipped with monitors, handles, buttons, switching or monitoring systems or devices that must be assembled before use, surgical instruments, etc. However, this process is mandatory for all types of devices, even for substance-based medical devices (e.g. creams, eye drops, mouthwashes, etc.) that do not have any particular components or systems that have to be assembled, activated and/or deactivated for operation.
Usability engineering is closely related to the user interface.
The user interface includes all the elements of the medical device with which the user interacts including the physical aspects of the medical device as well as visual, auditory, tactile displays and is not limited to a software interface. In particular, in the specific cases mentioned above (eye drops, creams and mouthwashes), the user interface is characterized by the primary packaging, which contains the formulations and which must, therefore, be handled appropriately to ensure the correct dispensing, application, closure and storage of the product, and by the IFUs and labelling, in terms of content, type and size of the characters used in writing the texts, to allow the user to clearly read and understand the provided information.
What is IEC 62366-1 required?
The medical device Usability assessment, as required by the IEC 62366-1:2015, is needed to identify, as part of the risk assessment, all those characteristics of the user interface related to medical device safety and potential user errors. Therefore, the Usability Engineering Process is closely linked to the Risk Management Process (ISO 14971:2019). The medical device usability assessment starts with the product specifications, its intended use, its principle of operation, its environment of use, its target population, its intended user, and its mode of use.
The IEC 62366-1 standard requires that all known and foreseeable hazards and hazardous situations at the user interface causing potential harm to the user/patient or third parties shall be identified. Once the hazards and hazardous situations associated with the use of the device have been identified, it is necessary to identify and describe the hazard-related use scenarios and for each of them to assess the severity of the possible harm.
The user interface shall be designed considering the product characteristics, the foreseeable user errors and the hazard-related use scenarios.
The summative evaluation is conducted on the user interface in order to verify that it is adequate to limit possible user errors and related potential harm. In addition, it is also needed to confirm that the product has appropriate labelling, IFUs and technical and design characteristics.
The summative evaluation is generally done by performing usability tests. During the test, all the hazard-related use scenarios or only those related to the most serious potential harms, previously identified, are tested. Usability testing is the manufacturer’s way of collecting objective data during simulated or actual use of the device.
IEC 62366-1 requires detailed documentation of the test conditions. In particular, a detail of the enrolled users, test environment (simulated or real), the device and any other conditions of use and user training measures. The manufacturer is free to choose whether to perform the test in a simulated or actual environment.
Finally, IEC 62366-1 specifies that the usability engineering process shall be performed by qualified personnel and that all the planned, carried out and assessed activities and test results shall be documented in an Engineering File.
What needs to be demonstrated in terms of usability by medical device manufacturers?
The Medical Device Regulation (EU) 2017/745 has further emphasized that the manufacturers shall demonstrate that their devices achieve their intended use safely and are effective for the clinical condition to be treated. In addition, the regulation stipulates that any risks associated with the use of the device, under normal conditions of use, can be considered acceptable compared to the expected clinical benefits to the patient.
Each manufacturer, performing a risk assessment, shall assess the medical device’s risks related to usability aspects and reduce the risks associated with reasonably foreseeable user errors and its design as far as possible.
Finally, each manufacturer shall demonstrate, with objective data, that he has verified that the user, for whom his device is intended, is put in a position to understand with absolute clarity the product principles of operation, the conditions of use, the environment of use, the warnings and contraindications, and any risks associated with its use.
PRINEOS, a strategic consulting company for Medical Devices and Pharma, bases its customers' satisfaction on the high quality of the services provided. Conducting precise and comprehensive usability is of fundamental importance; therefore, PRINEOS assist and supports Manufacturers in drafting the documents and defining the most effective approach to demonstrate the usability of medical devices.