Purpose: To characterize interventions needed by the population with visual impairment or to assess interventions in vision rehabilitation validated and standardized instruments used in different cultural contexts are necessary. The aim of this work was to characterize the functional status of a sample of people with visual impairment with the Portuguese version of the activity inventory (AI)

Methods: A group of participants in the study Prevalence and Costs of Visual Impairment in Portugal (PC-VIP) was recruit to face-to-face interviews and the activity inventory was administered. The AI examines 50 goals split between three objectives: social functioning, recreation and daily living. Goals rated ‘not important’ were skipped, but for all other goals the participant was asked to rate its difficulty on a five point scale ranging from ‘not difficult’ to ‘impossible without help’. The difficulty responses were Rasch analysed (Winsteps v3.81.0) to produce a continuous measure of visual ability (AI score). Additional information about distance and near visual acuity (ETDRS scale), contrast sensitivity (MARS test) and critical print size (MNREAD test) was collected.

Results: A total of 94 persons participated in this study. Some participants were not able to read or recognize letters due to their poor vision or poor literacy and were excluded from further analysis. Data reported here are from 62 participants, median age 63y (range=12-85) and the most common cause of visual impairment were retinal diseases. Mean presenting acuity in the better eye was 0.93logMAR (SD=0.5). The mean difficulty (item measure) in the AI was -0.33 logits (SD=0.96). The most difficult items were "sew or do needlework", "read the newspaper", "drive" and the easiest items were "provide care for a pet", "eat your meals", "use the restroom in a public place". The mean ability score (person measures) was 1.11 logits (SD=2.04). The ability measures in the AI were correlated with distance visual acuity (r=-0.57, p<.001), near visual acuity (r=-0.66, p<0.001), contrast sensitivity (r=0.62, p<.001) and critical print size (r=-0.60, p<.001).

Conclusions: Our results indicate that the AI scores in a sample of people Portuguese people with visual impairment were in line with what has been found in other cultural contexts. The visual ability measured by the AI was correlated with visual function assessed by different visual tests, which shows that this instrument can be used with confidence.