ViSIO-ObsRO

The 27-item ViSIO-ObsRO instrument is designed to assess impacts on vision-dependent ADL, mobility, and distal HRQoL experienced by children with RP/LCA (aged 3–11 years), on the basis of informant report (i.e., a caregiver of a child aged 3–11 years with RP/LCA). The ViSIO-ObsRO instrument requires parents/caregivers of children with RP/LCA to report the observed level of difficulty or frequency that a problem is experienced when their child is in specific situations or performing vision activities, over the “past 7 days.” Items are assessed on a 2- and 3-point verbal descriptor response scale. Three different response scales are used. An additional response option is provided for all items, for the parent/caregiver to select if they have not observed their child do that activity in the past 7 days, rendering the item not applicable.

Items within the ViSIO-ObsRO are grouped under the same four hypothesized domains as the ViSIO-PRO, assessing visual function symptoms (items 1–2), impacts on vision-dependent ADL (items 3–10), impacts on mobility (items 11–18) and impacts on distal HRQoL (items 19–27).

Translations of the ViSIO-PRO and ViSIO-ObsRO were informed by best-practice guidelines for translation, cultural adaptation, and linguistic validation, as outlined in the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) task force report, before their inclusion in this study [21].