What is the role of atropine (antimuscarinic agent) drops in treating myopia in children?

Atropine Eye Drops for Myopia Control in Children

Low-concentration atropine eye drops (0.05%) are the most effective pharmacological intervention for slowing myopia progression in children, with efficacy approximately double that of 0.01% concentration while maintaining a favorable safety profile. 1

Mechanism of Action and Efficacy

Atropine acts as a competitive antagonist of acetylcholine muscarinic receptors and appears to work through two mechanisms for myopia control:

1. Inhibition of accommodation, which may reduce forces on the eye that result in axial elongation
2. Inhibition of growth factors that elongate the eye, independent of accommodation 1

Multiple clinical trials provide strong evidence supporting atropine's effectiveness:

• A network meta-analysis of 30 randomized controlled trials (5,422 eyes) concluded that muscarinic antagonists like atropine were the most effective interventions for reducing myopia progression in children 1
• The LAMP study (Low-concentration Atropine for Myopia Progression) demonstrated a concentration-dependent response, with 0.05% atropine showing the optimal balance of efficacy and safety 2
• The efficacy of 0.05% atropine was approximately double that of 0.01% atropine in slowing myopia progression 1

Recommended Concentration and Administration

Based on the most recent evidence:

• 0.05% atropine is the optimal concentration, providing superior efficacy compared to 0.01% while maintaining a favorable side effect profile 1, 2
• Administration should be once daily, typically at bedtime to minimize daytime visual disturbances 3
• Treatment should be continued long-term, as studies show continued benefit in year 3 compared to stopping treatment 1

Potential Side Effects and Management

Low-concentration atropine has minimal side effects compared to higher concentrations:

• Common mild side effects: Blurred near vision, photophobia, ocular discomfort, dry eyes, and anisocoria 4
• Higher concentrations (0.1% and above) cause more significant visual disturbances and may require bifocal or multifocal eyeglasses for near work 1
• To minimize systemic absorption, digital pressure can be applied over the lacrimal sac and puncta after administration 5

Special Considerations and Precautions

• Age restrictions: Not recommended for children under 3 months of age; use should be limited to no more than one drop per eye per day in children under 3 years 6
• Rebound effect: A more significant myopic rebound was noted after 0.5% atropine treatment cessation compared to 0.01% 1
• Contraindications: Use with caution in patients with narrow angles or anatomical predisposition to angle closure 5
• Monitoring: Regular follow-up to assess myopia progression and potential side effects is essential

Combination Therapy

Some evidence suggests that combining atropine with other myopia control interventions may enhance effectiveness:

• A meta-analysis showed that myopia from axial elongation was lower in the group that received a combination of atropine and orthokeratology compared with orthokeratology alone 1
• Clinical trials are currently investigating the additive effects of combining orthokeratology and 0.01% atropine 7

Treatment Algorithm

1. Initial Assessment:

   • Confirm myopia diagnosis (-1.00 to -6.00 D range)
   • Rule out contraindications (narrow angles, history of angle closure)
   • Document baseline refraction and axial length

2. Treatment Initiation:

   • Begin with 0.05% atropine eye drops administered once daily at bedtime
   • Educate parents and children about potential side effects and proper administration

3. Follow-up Schedule:

   • Evaluate at 1,6, and 12 months after treatment initiation
   • Monitor for:
     • Changes in refractive error
     • Axial length changes
     • Side effects (photophobia, blurred near vision)

4. Treatment Adjustment:

   • If side effects are problematic, consider reducing to 0.025% or 0.01%
   • If myopia continues to progress rapidly (>0.5 D/year), consider combination therapy with other interventions

5. Long-term Management:

   • Continue treatment for at least 2-3 years
   • Consider gradual tapering rather than abrupt cessation to minimize rebound effect

By following this evidence-based approach, clinicians can effectively manage myopia progression in children, potentially reducing the risk of high myopia and associated complications later in life.