Measuring wearing times of glasses/patches using a well evaluated and safe orthodontic thermosensor device

Abstract

Purpose: Amblyopia is one of the most common visual disorders in children. The risk of severe visual impairment on the healthy eye is doubled in patients with amblyopia. If detected early enough chances of visual rehabilitation are good. Treatment consists of refractive correction and occlusion of the dominant eye. Patient compliance is an important factor and can be monitored using thermosensors. It was the goal of our study to give the proof of principle that wearing times of glasses and of patches can be measured using a comparatively small and commercially available microsensor.

Methods: Agreement between wearing times protocol and temperature measurements of three individuals was analysed using the Bland-Altman method. A wearing time diary was kept by all individuals, wearing times should be written down as accurately as possible. Commercially available TheraMon® microsensors and the TheraMon® reading station were lent by the Handelsagentur Gschladt (Hargelsberg, Austria). TheraMon® microsensor measures 9 x 13 x 4.5 mm in size and samples in regular intervals of 15 min with a storage capacitiy of 100 days and a battery capacity of 2 years. Sampling intervals are fixed at 15 min. Temperature sensitivity was set to 0.2°C. In order to monitor patching time, microsensors were attached on the inside of commercially available occlusion patches.

Results: Over a two-month period wearing times of patches or glasses were protocoled as 9556 min, while the microsensors detected 8891 min; mean wearing time was 137.0 min (protocol) and 133.3 min (microsensors) per day. There was an observed mean difference in overall wearing times of -5.7 min (95% CI -21.2 to 9.8). For glasses, the mean difference was -4.4 min (95% CI -25.1 to 16.3). For ocular patching, the mean difference between measured wearing times of the microsensor and the wearing protocol was -21.2 min (95% CI -72.8 to - 21.2552).It was always possible to distinguish the beginning- and endpoint of the wearing time. Different temperature transitions (e.g. pocket, or box, or worn above 30° C) showed different temperature profiles.

Conclusions: The TheraMon®-microsensor can reliably measure wearing times of glasses and ocular patches while having no discomfort for the bearer. Further studies on a larger number of individuals with different wearing profiles are needed.

Keywords: 417 amblyopia