Purpose
Visual functioning questionnaires (VFQs) can assess functional vision in individuals with mild to severe impairment, but are uninformative if remaining vision is minimal. We performed a systematic inventory of daily activities that require some, albeit minimal, visual guidance or support. These activities can then be assigned item difficulty scores through rating by profoundly impaired individuals, with the eventual purpose of extending the range of currently used VFQs.
Methods
Nine focus groups of 4-6 members with profound vision loss met in person or conference call to discuss the role of vision in their daily activities. The Massof Activity Inventory (Optom vis Sci 84:763-74;2007) was used as a template. Each group held 4-7 sessions of 60-90 min; audio recordings of the sessions were abstracted and analyzed for content. Reported activities were categorized into 4 domains - reading (R), mobility (M), visual motor (V), and visual information (I) -- and into 10 aspects -- brightness, contrast, lighting, movement, size, distance, depth, eccentricity, familiarity, and other.
Results
Focus groups reported 760 activities, with 10%, 17%, 24%, and 49% categorized in the R, M, V, and I domains, respectively. On average, 1.58 aspects of visual function were involved in each activity. Contrast (68%), brightness (27%), lighting (14%), size (14%), and distance (12%) were the most prevalent aspects that were critical in performing these activities, with eccentricity (8%), movement (7%), familiarity (5%), depth (1%), and other (2%) critical in smaller subsets of activities. A representative subset of these activities spanning all domains and visual aspects was used to create a set of 144 survey questions for a draft VFQ for ultra-low vision.
Conclusions
Even at these ultra-low vision levels visual activities in all 4 domains, and spanning all 10 aspects, of vision continue to be of critical importance. Following administration to a population of 100 profoundly impaired individuals and Rasch analysis, the resulting survey questions will be reduced to a set of ~50 questions spanning the lower end of the item difficulty scale largely untested by current VFQs. The selected activities also form the basis for training and assessment test in controlled environments, now being developed as part of the prosthetic low vision rehabilitation (PLoVR) curriculum.