Novel Patient-Reported Outcome Measure Validated for Peripheral Field Loss

A novel patient-reported outcome measure, the Low Vision Severely Constricted Peripheral Eyesight (LV-SCOPE) questionnaire, has been validated in individuals with severe peripheral field loss (PFL), according to research published in American Journal of Ophthalmology. 

“Existing disease specific [patient-reported outcomes] for glaucoma and [retinitis pigmentosa (RP)] are not adequately attentive to the challenges that individuals with severe [peripheral field loss] experience due to their vision loss, while general vision rehabilitation/low vision [patient-reported outcomes] suffer from a similar lack of applicability to this sizable population,” according to the study authors.

The research team developed a 127-item pilot questionnaire following a qualitative interview of 37 individuals with severe peripheral field loss due to glaucoma (n=18) or RP (n=19). Using data obtained from the interviews, the investigators began development of the novel patient-reported outcome measure by performing thematic content and matrix analyses to address relevant themes in both visually-limiting conditions, which included activity limitations, driving, emotional well-being, reading, mobility, and social function.

After creating the pilot questionnaire, 116 participants (median age, 69 years; 55.2% women) with severe peripheral vision loss (glaucoma, 69.8%; RP, 30.2%), who were recruited at a single eye center, completed the pilot questionnaire via telephone. The researchers analyzed response data using multivariate statistics and Rasch modeling.

The team eliminated 74 poorly functioning items from the instrument due to poor factor loadings, low internal consistency, high local dependency, low item information, item redundancy, or differential item functioning, leaving the novel patient-reported outcome measure with a total of 53 survey items and 6 domains. The domains (item numbers) included mobility (13), object localization (7), object recognition (8), reading (14), social functioning (5), and technology (6). 

An assessment of test-retest reliability of 18 participants showed no significant differences among the 6 domains of the novel patient-reported outcome measure, with intraclass correlation coefficients ranging from 0.70 for mobility to 0.87 for reading. The median time between initial and second administration of pilot questionnaire was 11 weeks.  

“The LV-SCOPE Questionnaire has strong psychometric properties and findings support the clinical utility of this instrument for assessing vision-related function among adults with severe [peripheral field loss],” according to the study authors. “This instrument fills a gap in the literature and the [patient-reported outcomes] available to clinicians and researchers aiming to assess vision-related function in this sizable and growing population.”

Study limitations include an overrepresentation of individuals who were non-Hispanic White in the study population, a small sample size for the test-retest assessment, and failure to include individuals with causes of severe peripheral field loss other than RP or glaucoma.

Disclosure: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.