The patient reported intraocular lens questionnaire (PR-ILQ): content validity, psychometric performance, and use in a regulated clinical trial to evaluate safety and effectiveness outcomes

BACKGROUND: Patient-reported outcomes (PROs) are underutilized in medical device evaluations, including in ophthalmology and intraocular lens (IOL) replacements. This article summarizes research conducted to develop the Patient-Reported Intraocular Lens Questionnaire (PR-ILQ) and support its content validity and psychometric performance. Use of the PR-ILQ in a regulated clinical trial to support new product approval decisions, secondary effectiveness claims, and safety observations is also discussed. RESULTS: The PR-ILQ, developed with ophthalmology experts (n = 10) and use of qualitative data generated from patients during concept elicitation (n = 44) and cognitive debriefing (n = 32) interviews, includes the Vision Correction Scale (VCS, three items), Vision Disturbance Scale (VDS, eight items), and IOL Replacement Satisfaction Scale (IOL-RSS, five items). Each assessment is distinct, and items within each are scored independently to address treatment benefit hypotheses. With its content validity established, the PR-ILQ was administered to 271 subjects (mean age = 68.3 years) participating in a clinical trial to evaluate the safety and effectiveness of an asymmetric segmented multifocal IOL (SBL-INI-02-13). Descriptively, item scores behaved as expected, with clustering of VCS and VDS scores at more- and less-severe levels at study entry and exit, respectively, though scores were distributed across response options across timepoints. Test-retest reliability results mostly indicate "fair"/"good" (weighted Kappa [KW]/intraclass correlation coefficient [ICC] > 0.40 to 0.60) to "excellent" (KW/ICC > 0.75) reproducibility for VCS, VDS, and IOL-RSS items in two independent analyses. Construct validity hypotheses, including those associated with sensitivity to change, were supported via correlational analysis showing a pattern of expected relationships among PR-ILQ items and with other variables including ratings of visual acuity. For example, reduced use of vision correction at near (r = -0.28), intermediate (r = -0.42), and far (r = -0.57) distances were more strongly related to overall lens satisfaction at end of study than improved visual acuity at those same distances (r = -0.25. -0.26, and -0,14). CONCLUSIONS: The PR-ILQ is content valid and early evidence suggests it is capable of producing reliable scores upon which valid conclusions may be drawn when administered among patients undergoing cataract lens replacement surgery. Acknowledging limitations and need for additional psychometric evaluation, the assessment recently supported a new product approval decision, secondary effectiveness claims, and safety observations. Together, this indicates that the PR-ILQ, along with the evidentiary basis and suggestions for use presented herein, will be of immediate value to IOL replacement outcomes researchers, regulators, and other stakeholders interested in generating evidence to inform health care decisions and improving cataracts patients' lives. TRIAL REGISTRATION: Clinicaltrials.gov, NCT02487160. Registered 25 June 2015, https://clinicaltrials.gov/study/NCT02487160 .