Occlusion Treatment for Amblyopia: Assessing the Performance of the Electronic Occlusion Dose Monitor

Abstract

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.

Electronic monitoring of occlusion treatment for amblyopia in patients aged 7 to 16 years

“…Diaries were written by the families in addition, so that lack of ODM data due to loss or occasional technical failure of the ODM could be compensated for. It had been noticed previously that there was good agreement with diaries when the patients and their parents knew that occlusion was electronically monitored, even when compliance with treatment was low [26]. As those findings in younger patients do not necessarily apply to the present age group, care was taken to evaluate the agreement between ODM recordings and diaries promptly when both where available, and to give the families feedback about any disagreement.…”

“…Start time as well as end time of occlusion was evaluated for each day, and the daily occlusion period was calculated. The devices have been shown to record reliably [23][24][25], also in long-term continuous measurements [26]. For reasons of battery and data storing capacity, the ODM was exchanged every 10 to 20 days, either during patients' visits to the research unit, or during home visits by researchers.…”

Efficiency of electronically monitored amblyopia treatment between 5 and 16years of age: New insight into declining susceptibility of the visual system

“…Crowded Landolt ring charts with optotype separation 2.6 minarc (Oculus, Wetzlar, Germany) presented at 40 cm distance were used for all patients. Occlusion was recorded using more recent versions of the ODM developed in the Netherlands (Simonsz et al, 1999), which were tested and applied for continuous recording in several previous studies (Awan, Proudlock, & Gottlob, 2005;Chopovska et al, 2005;Fronius, Bachert, & Lüchtenberg, 2009;Fronius et al, 2006;Kracht et al, 2010). Being taped to the occlusion patch, they measure the temperature difference between the patch on the eye and the surroundings.…”

Response to “Mehdi-ODM; a modified digital monitoring of the occlusion therapy for amblyopia”

“…Garebaghi et al discuss possible limitations of using temperature difference for occlusion treatment monitoring. This pertains also to our earlier articles [6,7] in which, after extensive testing under various conditions, we described in detail the advantages and disadvantages of either technique. There was a certain ambient temperature range (33°to 37°C) where the recordings with patch and ODM on the eye were close to baseline recordings (ODM in a box) and thus difficult to identify as patching episodes.…”

“…On the other hand, the Dutch devices were able to give hints as to whether the patch was attached to parts of the body other than the eye [6,7], which is not discernible with devices with electrode leads or electrodermal sensors [4,and Garebaghi et al].…”