Patient-Reported Spectacle Independence Questionnaire (PRSIQ): Development and Validation.
OBJECTIVE
To develop a questionnaire quantifying spectacle independence following cataract surgery.


METHODS
Questionnaire design and validation study.


METHODS
A literature review, expert clinical interviews, and patient interviews were undertaken to develop a patient-reported questionnaire assessing spectacle independence. Draft items were assessed and revised in a series of cognitive interviews where the instructions, recall period, and response categories were evaluated for understandability and consistency. The final draft items were evaluated in 2 quantitative studies. Confirmatory factor analyses, including item response theory calibration, were performed; reliability estimates were obtained; and validity analyses of the resulting scores were carried out.


RESULTS
Qualitative research demonstrated that patients often considered themselves spectacle independent yet, when probed, it was determined that the respondent actually wore correction for certain activities. Moreover, despite what the respondents claimed about needing to wear correction and their actual use of correction, there were various levels of function reported when carrying out activities at several different distances without the use of correction. Using the qualitative results, the Patient-Reported Spectacle Independence Questionnaire (PRSIQ) was developed to assess spectacle independence via items that assess what patients say and do, and how they function at various distances. All quantitative analyses (eg, discriminant and convergent validity correlations, known-groups analyses) conform to predictions and support the use of the PRSIQ as a measure of spectacle independence.


CONCLUSIONS
The PRSIQ is a patient-reported measure assessing spectacle independence following cataract surgery. The analyses conducted provide evidence for the use of the PRSIQ total score as a measure of spectacle independence.
PRO-Spectus, San Diego, California. Electronic address: rmorloc1@yourcarechoice.com.
Robert
R
Morlock
Vector Psychometric Group, Chapel Hill, North Carolina.
R J
RJ
Wirth
Health Services Research Center, University of California-San Diego, La Jolla, California.
Steven R
SR
Tally
Clinical Research-Santa Ana, Abbott Medical Optics Inc, Santa Ana, California.
Carrie
C
Garufis
Department of Ophthalmology, Shiley Eye Institute, University of California-San Diego, La Jolla, California.
Christopher W D
CWD
Heichel
D002387:Cataract Extraction / Q000523:psychology*; D005139:Eyeglasses / Q000592:standards*; D006801:Humans; D017060:Patient Satisfaction; D011594:Psychometrics / Q000379:methods*; D036301:Qualitative Research; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*