Abstract
Abstract: :
Purpose: The broad-band muscarinic antagonist, atropine, is believed to have a therapeutic affect in reducing the progression of axial myopia in humans via a non-accommodative mechanism. It is still unclear, however, whether long-term atropine usage would alter the retinal function via two possible mechanisms namely retinal toxicity and photic retinopathy. The aim of this study was to investigate the effects of long-term atropine usage on retinal function. Methods: A multifocal electroretinogram (mfERG) was recorded in 104 subjects whom have been involved in the randomized, double-masked, placebo-controlled ATOM (Atropine in the Treatment of Myopia) study, which currently being conducted at Singapore Eye Research Institute. Subjects in the atropine group (n=48) received one drop of atropine (1%) in the randomised eye for 2 years. Subjects in the control group (n=56) received vehicle eye drops with similar dosage and duration. All ERG recordings were performed within the second and third month after the subjects had stopped their last instillation. Results: The means of the a- and b-wave response amplitude of the non-randomised eye in the control group were 6.4 and 11.5 µV, respectively. The inter-ocular differences in the ERG responses of the control group were not significant. The ERG responses from both eyes of the atropine group were reduced in comparison to the control group, although these were not statistically significant. No difference in the response implicit time between the groups was found. Conclusions: Subjects treated with atropine show slightly reduced multifocal ERG amplitudes, without changes in implicit time. The amplitude reduction is unlikely to be related to light damage because the atropine treated and fellow eye are similarly affected. The reduction in ERG response amplitude in the fellow eyes of the atropine group might be due to a systemic effect. The clinical implications of these findings need to be further explored.