The IVIS was based on items derived from the Functional Capacities Assessment developed by the Michigan Commission for the Blind. This five-item instrument provides an assessment of difficulties with simple visual tasks such as reading and watching television. The IVIS is one of the components of the MSQLI
Administration time is approximately 2-3 minutes.
The IVIS is a structured, self-report questionnaire that the patient can generally complete with little or no intervention from an interviewer. However, patients with visual or upper extremity impairments may need to have the IVIS administered as an interview. Interviewers should be trained in basic interviewing skills and in the use of this instrument.
The IVIS is easy to administer and focuses on the ways in which MS-related visual problems affect everyday activities such as reading, watching television, recognizing house numbers, etc. Given the very practical nature of the issues it covers, the scale has high face validity for patients. The IVIS itself does not involve any objective visual examination such as a visual acuity test with a Snellen chart and it does not assess the cognitive aspects of vision such as the processing of visual information.
The IVIS has a Cronbach's alpha of .86. In the original field testing of the MSQLI of which it is a part, the IVIS was significantly correlated with Visual item of the Kurtzke Functional Systems and with visual acuity.