Low vision quality of life assessment: Psychometric validation of Portuguese version of NEI-VFQ 25

The goal was to make the validation, for the Portuguese people of a functional vision measurement instrument, that could be used to help characterise a situation of low vision and to evaluate a visual rehabilitation process results. An American visual functioning questionnaire was applied to a 100 individuals group, after being made its cultural and linguistic adaptation to Portuguese. Simultaneously, a general health condition related quality of life questionnaire was applied, to obtain the health condition’s perception and to establish the NEI-VFQ 25’s specific scales’ validity, intended to evaluate the loss of vision’s influence in the health’s physical and mental aspects. Two visual functions were assessed to the same individuals: visual acuity and visual fields. The relation between the actual evaluated values of the visual functions and the questionnaires responses was studied. It was observed that there is a relation between the best scores of visual functions values and the high scores in responses obtained in the different scales of the visual functioning questionnaire. It was concluded that the NEI-VFQ-25 could be considered a valid measurement instrument for the goals described