Occlusion treatment for amblyopia: assessing the performance of the electronic occlusion dose monitor

Electronic Occlusion Dose Monitors (ODMs) are a fairly recent development. As part of the international Electronic Recording of Patching for Amblyopia Group (ERPAG), we are the first center in Germany to apply these devices. The aim of our independent study was a further assessment of their potential, including technical features and the practicability of long-term use under near-clinical conditions. The ODMs, taped to the occlusion patch, measure the temperature difference between the surface of the eye and the surroundings. Investigators and patients' families kept occlusion diaries while using ODMs. Measurements were performed on the eye (patch tight or detached), forehead, arm and in trouser pockets, and while varying the room temperature. Patients' occlusion was monitored for several months together with acuity development. ODM acceptance was assessed by questionnaire. Written and monitored occlusion times corresponded excellently. Proper measurements on the eye could be distinguished more readily from those with the patch detached or in the pocket than from measurements on the arm and forehead. Very high temperatures (33-37 degrees C) prevented reliable measurements. Using ODMs was convenient for parents but time-consuming for researchers. Despite occasional data loss (incomplete diaries, ODM failure), acuity development could be followed as a function of monitored occlusion dose. This study contributes to the specification of the ODM features and their refinement for clinical use.