A new efficient and comprehensive asthenopia questionnaire

Abstract

Background: There has been no standardized questionnaire and objective criterion for assessing and diagnosing asthenopia so far. This study aimed to design a valid and reliable questionnaire to determine the various causes of asthenopia for use by clinicians and researchers. Methods: We developed a 19-item asthenopia questionnaire (AQ-19) in two phases. In the Design phase, 17 experts, 98 patients with asthenopia and 20 controls participated to generate the item list. We generated a comprehensive 52-item list to create our 1st version. The list included selected items based on a literature review, patient interviews and the Delphi experts method. In the Validation phase, we conducted a pilot test (127 patients and 25 controls) and retest (154 patients and 24 controls) for item reduction and a questionnaire validity assessment. Results: Our initial questionnaire contained 52 symptoms and 2 self-evaluation questions. After item reduction and assessment, we generated a 19-item questionnaire. It included 19 symptom items that were classified into three domains through factor analysis. Cronbach's α for the three subscales of this version were between 0.79 and 0.85, while for the complete questionnaire Cronbach's α was 0.90, with a split-half reliability of 0.80. Factor analysis showed the three components have eigenvalues > 3 and these explained 54.3% of the variance. Conclusions: The AQ-19 has acceptable psychometric properties, making it a valid and reliable tool for ophthalmologists and optometrists to evaluate asthenopia as well as to provide clues to find its causes. It provides three levels of information: (1) Identifies the presence of asthenopia. (2) Differentiates three major causal classifications (ocular-surface, systemic, and vision symptoms). (3) Focuses in on a specific cause. The clinician must still use his or her skills to determine the exact cause. The AQ-19 questionnaire has the potential to be used in clinical trials and outcome research, and most importantly to help clinicians efficiently and effectively diagnose the cause of a patient’s asthenopia. Trial registration: KYK [2016]8. Registered at 25 February 2016. Retrospectively registered. Keywords: Asthenopia, Reliability, Validity, Questionnaire, Delphi Method