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Gislin Dagnelie; Ultra-Low Vision (ULV) assessment: Properties of vision that is close to blindness. Journal of Vision 2017;17(15):40. doi: 10.1167/17.15.40.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Ultra-low vision (ULV) is defined as profound visual impairment that only allows perception of crude shapes, movement, and light sources. We have developed questionnaires and assessments of functional vision to quantify ULV.
Methods: Following an inventory of visual activities among 46 members of 9 focus groups we created a 150-item visual functioning questionnaire (ULV-VFQ) and calibrated it through two rounds of administration and Rasch analysis in 80–90 ULV individuals; 50-, 23- and 17-item and adaptive versions were also created. An activities of daily living (ADL) assessment – 17 items, each at 3 difficulty levels – was created and calibrated through administration and Rasch analysis in 25 ULV individuals, 4 Argus II recipients and 6 Brainport users.
Results: 760 activities were reported for which ULV was helpful; these were categorized according to visual domain (detail, visual information, visual-motor, and mobility) and visual aspect (contrast, lighting, size/distance, speed, familiarity, and eccentricity). Questionnaire items and ADLs were selected to represent all aspects and domains and spanned 6.2 logits, centered on the 9.7 logit participant visual ability range. Principal Components Analysis showed that a single ability dimension described the data. ULV-ADL test results show that a battery of 30 activities will be sufficient to estimate visual ability, and that Argus II and Brainport users are captured within the same ability dimension.
Conclusions: ULV is distinct from “ordinary” low vision, but can be reliably assessed using appropriate measures, both self-report and performance. We are designing a ULV rehabilitation curriculum built on the same principles
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