ICF core set visual impairments

Public health

Lorenzo Billiet, deputy director of ‘Blindenzorg Licht & Liefde’ in Belgium and PhD candidate, is developing an International Classification of Functioning of dissability and health (ICF) core set for vision loss in adults and elderly with irreversible eye condition.


Lorenzo Billiet


PhD candidate, adj.dir. Blindenzorg Licht & Liefde





ICF core set visual impairments

Why are we doing this study?

Vision plays an important role because it combines about 80% of the function of all five senses. Loss of vision will cause limitations in all areas of life (mobility, daily activities, leisure,…). Visual tasks are often required to perform activities or participate in social life. Worldwide an estimated 36 million people are blind and 216 6 million people have moderate to severe visual impairments and an additional 188.5 million people have mild visual impairments. The older we get, the more often visual impairment will occur. Given the demographic evolution, this is quite a challenge.

What is the aim of this study?

The aim of the study is to arrive at a selection (the core set) from the total International Classification of Functioning (ICF), which consists of 1400 categories that define a person’s functioning, that is specifically applicable to blind and partially sighted people. adults and the elderly.

The core set will contribute to better communication and data interchangeability, which in turn will contribute to a higher quality of life. In this way, the elderly can live longer at home in their familiar environment. On the other hand, it will also be possible to work from a holistic and client-oriented perspective with the necessary empowerment and from an inclusive character.

How do we conduct this study?

The research will be conducted in three phases. The first phase is a preparatory phase that consists of several sub-steps, including an extensive literature study supplemented with a survey of various stakeholders spread over the different WHO regions. The second phase of the project is to organize an international consensus conference where a group of experts, through a consensus process, confirm the core set. In the final phase, the core set will be implemented within the clinical setting.


Prof.dr. Ruth M.A. van Nispen, Prof.dr. D. van der Velde (Universiteit Gent)

Detailed description

An ICF core set is a tailored shortlist of ICF categories that describe the functioning and disability of a specific group of people. Within the core set we make a selection of essential categories that are most relevant for describing the functioning of an adult or older person with an irreversible visual impairment. To date, 34 ICF core sets have already been developed, 1 of which focuses on the sensory aspect.

The aim of this project is the development of an internationally accepted, evidence-based, reliable and valid ICF core set for vision loss caused by irreversible eye disorders in adults and the elderly.

An ICF core set is a list of ICF categories that describes as concisely as possible the typical spectrum of problems in the functioning of people with irreversible vision loss. It includes all aspects of functioning, activities and external environment that need to be assessed in order to get the most complete picture of a person with irreversible vision loss. The items found about functioning included within the core set can be translated at a later stage into various assessment instruments, such as questionnaires, assessment systems, structured interviews, observation scales and the like that can be used within a clinical setting. Depending on the needs and wishes of the user, further focus can be placed on improving the quality of life.

The core set will be developed in three phases:

  1. the preparatory phase,
  2. an international consensus phase and
  3. the validation phase in which the ICF core set can be validated and implemented within the clinical setting.


In the preparatory phase, we start from a literature study, after which a survey is conducted among visually impaired and blind adults and the elderly, supplemented with the opinions of stakeholders who are in contact with people with a visual impairment through their professional careers. And this across different continents.

The next phase of the project is to organize an international consensus conference to validate the collected information in order to arrive at an internationally accepted ICF core set for visual impairment in adults and the elderly with irreversible eye disease. In the last step we look at the implementation of the core set.