The Surprising Twist in Myopia Management: When Treatment Causes Esotropia
Myopia, a growing concern worldwide, especially in children, has found an effective ally in low-dose atropine 0.01% (LDA). This treatment has shown remarkable success in slowing axial elongation while minimizing side effects. However, a rare complication has emerged, leaving clinicians intrigued and patients perplexed. We present a unique case where a child's short-term LDA treatment led to acquired esotropia, a condition where the eyes turn inward, causing double vision.
The Case Unveiled
An 8-year-old boy, with a family history of high myopia, sought help for deteriorating vision. His initial examination revealed a significant increase in axial length, prompting the initiation of 0.01% atropine sulfate eye drops. But here's where it gets intriguing: after three months, he reported binocular double vision. The diagnosis? Comitant intermittent esotropia, a condition rarely associated with LDA.
Unraveling the Mystery
The patient's condition improved with multifocal soft contact lenses, which resolved diplopia and restored binocular fusion. This led to the discontinuation of atropine treatment. But why did this happen? Several factors may have contributed. The child's high myopia, combined with the strain of high-minus lenses and a short working distance, could have triggered excessive convergence demand. Additionally, atropine's partial cycloplegia effect may have induced residual accommodation, leading to increased accommodative convergence through the AC/A ratio relationship.
A Complex Web of Interactions
The relationship between atropine and binocular vision is intricate. While atropine can interfere with accommodation, LDA's partial cycloplegia allows some accommodation to persist. This residual effort can trigger excessive convergence, potentially causing esotropia. Interestingly, full cycloplegia, as with 1% atropine, eliminates this risk by completely suspending accommodation. But that's not all. The anticholinergic effect of atropine may also play a role, enhancing central accommodative effort and potentially contributing to esotropia. This phenomenon has been observed with systemic anticholinergics, further complicating the picture.
Navigating the Controversy
The case highlights a controversial aspect of LDA therapy. While it's effective for myopia control, it can induce esotropia and binocular disruptions. This raises questions: How should clinicians balance myopia control and binocular function? When esodeviation occurs, is discontinuing atropine the best approach? And what alternative treatments can effectively manage myopia while preserving binocular vision?
A Call for Further Exploration
This case underscores the need for comprehensive monitoring of binocular vision parameters during LDA therapy, especially in patients with high myopia or pre-existing binocular dysfunction. It also emphasizes the importance of considering alternative treatments, such as multifocal soft contact lenses, which have shown promise in myopia control without disrupting binocular function. As we navigate the complexities of myopia management, further research is crucial to optimize treatment strategies and ensure the best outcomes for patients.
What are your thoughts on this intriguing case? Do you think the benefits of LDA outweigh the risks, or should clinicians exercise caution when prescribing it?
