Psychometric Validation of the ViSIO-PRO and ViSIO-ObsRO in Retinitis Pigmentosa and Leber Congenital Amaurosis

M Dominik Fischer; Francesco Patalano; Christel Naujoks; Judit Banhazi; Christine Bouchet; Paul O'Brien; Christine Kay; Jane Green; Todd Durham; Helena Bradley; Nicola Williamson; Melissa Barclay; Joel Sims; Isabelle Audo

doi:10.1007/s40123-023-00670-8

Psychometric Validation of the ViSIO-PRO and ViSIO-ObsRO in Retinitis Pigmentosa and Leber Congenital Amaurosis

Ophthalmol Ther. 2023 Apr;12(2):1359-1386. doi: 10.1007/s40123-023-00670-8. Epub 2023 Feb 27.

Authors

M Dominik Fischer^{1

2

3}, Francesco Patalano⁴, Christel Naujoks⁴, Judit Banhazi⁴, Christine Bouchet⁴, Paul O'Brien⁵, Christine Kay⁶, Jane Green⁷, Todd Durham⁸, Helena Bradley⁹, Nicola Williamson¹⁰, Melissa Barclay¹⁰, Joel Sims¹⁰, Isabelle Audo¹¹

Affiliations

¹ Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
² Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
³ Centre for Ophthalmology, University Hospital Tuebingen, Tuebingen, Germany.
⁴ Novartis Pharma AG, Basel, Switzerland.
⁵ Novartis Ireland Ltd, Dublin, Ireland.
⁶ Vitreoretinal Associates, Gainesville, FL, USA.
⁷ Discipline of Genetics, Faculty of Medicine, Memorial University of Newfoundland, Craig L Dobbin Genetics Research Centre, St. John's, Canada.
⁸ Foundation Fighting Blindness, Columbia, MD, USA.
⁹ Adelphi Values Ltd, Bollington, Cheshire, UK. helena.bradley@adelphivalues.com.
¹⁰ Adelphi Values Ltd, Bollington, Cheshire, UK.
¹¹ Institut de la Vision, CHNO des Quinze-Vingts, National Rare Disease Center REFERET and INSERM-DGOS CIC 1423, Sorbonne Université, INSERM, CNRS, 75012, Paris, France.

Abstract

Introduction: Retinitis Pigmentosa (RP) and Leber Congenital Amaurosis (LCA) are rare inherited retinal degenerative disorders. The Visual Symptom and Impact Outcomes patient-reported outcome (ViSIO-PRO) and observer-reported outcome (ViSIO-ObsRO) instruments were developed in this population to assess visual function symptoms and impacts on vision-dependent activities of daily living (ADL) and distal health-related quality of life (HRQoL). This study aimed to explore the psychometric properties of the ViSIO-PRO and ViSIO-ObsRO in RP/LCA.

Methods: The 49-item ViSIO-PRO and 27-item ViSIO-ObsRO instruments were completed by 83 adult and adolescent patients and 22 caregivers of child patients aged 3-11 years with RP/LCA, respectively, at baseline and 12-16-day follow-up. Concurrent measures were also administered at baseline. Psychometric analyses assessed item (question) properties, dimensionality, scoring, reliability, validity, and score interpretation.

Results: Item responses were mainly evenly distributed across the response scale, and inter-item correlations were mostly moderate to strong (> 0.30) at baseline within hypothesized domains. Item deletion was informed by item properties, qualitative data, and clinical input and supported retention of 35 ViSIO-PRO items and 25 ViSIO-ObsRO items. Confirmatory factor analysis in line with pre-hypothesized domains supported a four-factor model assessing visual function symptoms, mobility, vision-dependent ADL, and distal HRQoL. A bifactor model supported calculation of total scores and four domain scores. Internal consistency was high for domain and total scores (Cronbach's alpha > 0.70) and test-retest reliability for total scores was strong between baseline and 12-16-day follow-up (intraclass correlation coefficients 0.66-0.98). Convergent validity was supported by strong correlations in a logical pattern with concurrent measures. Mean baseline scores differed significantly between severity groups. Distribution-based methods provided initial insights to guide interpretation of scores.

Conclusions: Findings supported item reduction and established scoring of the instruments. Evidence of reliability and validity as outcome measures in RP/LCA was also reported. Further research is ongoing to explore responsiveness of the ViSIO-PRO and ViSIO-ObsRO instruments and interpretation of change scores.

Keywords: Clinical outcome assessment; Inherited retinal disease; Leber congenital amaurosis; Observer-reported outcome; Patient-reported outcome; Psychometrics; Retinitis pigmentosa.