The Amblyopia Quality of Life (AmbQoL): Development and Content Validation of a Novel Health-Related Quality of Life Instrument for Use in Adult and Pediatric Amblyopia Populations

IntroductionAmblyopia is a neurodevelopmental vision disorder, characterized by poor vision in one or both eyes. Given the lack of existing clinical outcome assessments (COA) considered fit-for-purpose for amblyopia clinical trials, this study developed new COAs to assess amblyopia symptoms and health-related quality of life (HRQoL) impacts in adult and pediatric amblyopia populations that conform with best practice standards and regulatory guidelines.MethodsFindings from a targeted qualitative literature review informed the development of three versions of the new Amblyopia Quality of Life Questionnaire (AmbQoL): a patient-reported outcome measure (PRO) for individuals aged 13 years and older, a PRO for children aged 9-12 years, and an observer-reported outcome measure (ObsRO) for caregivers of children aged 4-8 years. Qualitative interviews were conducted with the target populations, and with ophthalmologists experienced in treating amblyopia patients to evaluate the content validity for further development of the AmbQoL. A translatability assessment was conducted to ensure cultural appropriateness and usability across multiple languages. Feedback from Food and Drug Administration (FDA) was also sought on the instruments, and clinical experts provided input at key stages.ResultsInterviews were conducted with 112 patients/caregivers and ten ophthalmologists from the USA, France, and Germany. The instructions, items, and response options were well understood across all AmbQoL versions. Feedback from the patients, caregivers, ophthalmologists, the translatability assessment, the FDA, and the expert clinicians informed minor wording modifications to enhance clarity and translatability. Some items were removed due to low relevance. The study resulted in a 23-item adult/adolescent PRO, 24-item child PRO, and 12-item ObsRO, each employing a 7-day recall period.ConclusionEach AmbQoL version has documented support for its face and content validity for use in amblyopia populations aged >= 4 years. Further research is necessary to evaluate the psychometric measurement properties of the AmbQoL instruments to enable their use in amblyopia treatment trials.