In the UK, rehabilitation services to the blind and partially sighted people is provided by specialist trained personnel in the Social Services Department. For many years there has been controversy about the kind of information which ophthalmologists should pass to the Social Services Department about a patient. Social workers claim that clinical information is essential to their decision making about rehabilitation of a visually handicapped person, whereas ophthalmologists assert that such information is subject to the general principles of medical confidentiality and should therefore only be available to medical colleagues. In an attempt to solve this dilemma a study was carried out to determine what information social workers actually use in making decisions for the rehabilitation of a visually handicapped person. A nationwide sample of specialist social workers was interviewed using a repertory grid procedure. Factor analysis and cluster analysis of the data revealed four principal categories of information were being used for decisions about rehabilitation. These were: 1) aspects of visual function, 2) general health, 3) level of social and financial support and 4) personal traits and aptitudes. The greatest number of discriminations made was in terms of a client's personal traits and aptitudes, while aspects of visual function accounted for only 11% of all the sources of information used. Clinical information about a patient's diagnosis was not used by the social workers. The results have been used to assist inter-professional communication by deriving both qualitative and quantitative scales for transmitting information about a patient/client from ophthalmologists to social workers. These findings are likely to have considerable significance to the practice and optometric management of patients with low vision.