Our suite of validated PROMs measures the impact of vision impairment on vision-related quality of life in different populations.
They are available in paper-pencil or digital format. The digital format is strongly recommended as it mitigates the need for data entry and calculation of raw scores.
The Impact of Vision Impairment (IVI) questionnaire
The 28-item IVI measures the impact of vision impairment on vision-related quality of life in adults.
The IVI provides an overall score, and three subscale scores:
Reading and Accessing Information
Mobility and Independence
Emotional well-being
It has been extensively validated in clinical and population-based studies, and various eye conditions, including age-related macular degeneration, glaucoma, cataract and diabetic retinopathy.
The IVI has been used in numerous intervention studies, including Phase 3 randomised controlled trials, and is responsive to treatment and low vision vision rehabilitation.
The IVI is available in more than 20 Languages
Linguistic validation has been conducted according to ISPOR guidelines
Main Publications on IVI validation
Original version of IVI – 32 items
Rasch analysis of IVI - 28 items
Rasch analysis of domain structure of the IVI – 28 items
Pooled item calibrations – 28 items
Publications using the IVI in other languages and eye conditions
Brief Impact of Vision Impairment Questionnaire (B-IVI)
The Brief IVI (or B-IVI) is a 15-item version of the original IVI, with similarly robust psychometric properties. The B-IVI provides an overall measure of vision-related quality of life, and two subscales scores:
Vision-specific functioning
Emotional well-being
The B-IVI is endorsed by the International Consortium for Health Outcomes Measurement (ICHOM) to measure the quality of life impact of age-related macular degeneration
Impact of Vision Impairment for Children (IVI_C)
The IVI_C is a valid and reliable questionnaire to measure vision-related quality of life in children with vision impairment. It was the first paediatric vision-related quality of life questionnaire developed primarily from the perspectives of children.
The IVI_C comprises 24 items that focus on interaction and classroom dynamics and provides an overall score of vision-related quality of life.
It has been widely used in Australia, India, south-east Asia and the Pacific, the Caribbean, the UK, and the USA.
Main Publications on IVI_C Validation
Development of the original version of the IVI_C
Rasch analysis of the IVI_C
Publications using other language versions of the IVI_C
Impact of Vision Impairment in Residential Care (IVI_RC)
The IVI_RC measures vision-related quality of life in people living in residential care facilities and nursing homes. It has been used in residential care populations in Australia and Singapore.
The IVI_RC comprises 28 items and provides three separately scored scales:
Reading and Accessing Information
Mobility and Independence
Emotional well-being
Main Publications on the IVI_RC
The Residential Ocular Care (ROC) Multi-Centered Randomized Controlled Trial.
Scoring and data analysis for the IVI suite
Scores for the IVI suite can be calculated using simple summed scoring. However, due to the limitations of summed scoring, we recommend that Rasch analysis is conducted on the raw data.
Rasch analysis provides
A quality control system to optimise the psychometric properties of a questionnaire, such as precision, unidimensionality, item ‘fit’, targeting, and item bias.
A way to convert ordinal scores into interval-level estimates.
Improved measurement precision and increased sensitivity to detect change in scores over time.
If you would like assistance with Rasch analysis,
please contact us as part of our consultancy services.
IVI-CAT
IVI-CAT is a computerized adaptive testing (CAT) system that measures the impact of vision impairment on vision-related quality of life.
The IVI-CAT is based on the original 28-item paper-pencil IVI questionnaire, and the CAT algorithms were developed using data from patients with vision impairment and low vision.
IVI-CAT provides precise measurement vision-related quality of life using only 5–10 items, a reduction in items of 65-82% from the original paper-pencil IVI.
IVI-CAT provides precise measurement of overall
vision-specific quality of life and two sub-domains.
Vision-specific functioning
Emotional well-being
Publications
Development, psychometric testing and CAT simulations using data from over 800 patients with vision impairment.
Utilisation
IVI-CAT is currently being implemented in Refractive Surgery Department at the Singapore National Eye Centre to measure the impact of vision impairment and laser surgery on vision-related quality of life.
