Objective Measurement of Spectacle Wear Time with a Temperature Sensor Data Logger

Purpose: Many practitioners and researchers desire to objectively quantify spectacle wear time. The purpose of this study was to evaluate the Smartbutton Data Logger Temperature Recorder for monitoring spectacle wear. Methods: Fifty adults (32 female, 18 male) wore a thermosensor on their spectacles for 2 weeks for each of 2 mount types while keeping wear diaries. Temperatures during reported spectacle wear (ON) were compared to temperatures during non-wear (OFF). The success of two methods to approximate wear time was evaluated by percent error with respect to subject reported wear time. The first filtered temperatures, defining wear time from temperature ranges determined from group or individual mean temperatures calculated during subject-reported ON times. The second utilized examiners interpreting temperature versus time plots to identify spectacle wear. Results: Group mean ON (31.8 ± 0.6 ⁰C) and OFF (24.7 ± 1.5 ⁰C) temperatures differed significantly (p<0.001), female ON temperatures averaged 1⁰C higher than males (p=0.04), and there was no significant difference in temperature between mounts (p=0.18) by repeated measures ANOVA. Median percent error and first and third quartiles (Q1, Q3) of each approximation technique was: group mean filtering = 8% (Q1 3%, Q3 18%), individual mean filtering = 7% (Q1 4%, Q3 19%), examiner 1 = 6% (Q1 2%, Q3 14%), examiner 2 = 7% (Q1 3%, Q3 12%). Evaluation of the most detailed diaries (8 subjects) revealed that brief wear intervals and leaving spectacles in a warm, parked car resulted in higher percent error in approximating wear time. Conclusions: The SmartButton is a promising device to monitor spectacle compliance in patients with all approximation methods evaluated providing less than 10% median percent error in wear time.