Objective compliance, dose, and response for atropine penalization amblyopia treatment

Abstract

Purpose: According to previous studies, a daily regimen (7 drops a week) of atropine penalization is equally effective to a 2-drop regimen (2 drops a week) in treating moderate and severe amblyopia. These results suggest that the dose-response relationship of atropine penalization is not fully understood. Parental self-reported subjective compliance to atropine penalization ranges from 59% to 94%.(PEDIG, 2002, 2008, 2009) Objective measurement of compliance to atropine penalization has not been reported. This study aims to investigate objective compliance, dose, and vision improvement response to atropine penalization in amblyopic children.

Methods: Twelve amblyopic children (3-8yr; 20/40-20/125 in the amblyopic eye, not previously treated with atropine) were enrolled. Twice weekly or daily regimen was prescribed by physicians. To measure objective compliance, we used Medication Event Monitoring System (MEMS) caps, which are designed to record the time and date when the bottle was opened. Objective compliance was calculated as the ratio of MEMS weekly recording times to weekly regimen. Participants were provided a calendar log to report subjective compliance and were scheduled for follow-up visits at 4 and 12 weeks. To measure the usage of atropine, we weighed the atropine eyedropper before and after treatment. Visual acuity was measured with ATS-HOTV. Correlation of visual acuity improvement with total atropine usage and regimen were calculated.

Results: At 4 weeks, objective compliance averaged 78% (range 57-100%), while subjective compliance was reported to be 84% (range 64-100%). At 12 weeks, the average objective compliance was 62% (range 41-100%), while subjective compliance was 84% (range 78-100%). Interestingly, we found that the twice a week regimen had significantly higher objective compliance than the daily regimen (p=0.03). Visual acuity in the amblyopic eye improved 0.23±0.18logMAR. Data suggests that visual acuity improvement is correlated to total atropine usage (R-squared =0.73), instead of regimen (R-squared =0.10).

Conclusions: Objective compliance with atropine instructions can be monitored with MEMS, which may facilitate more effective communication between clinicians and patients. Our pilot data showed that objective compliance with atropine penalization treatment decreases over time and varies with regimen. On average, subjective parental reporting of compliance is overestimated.