What is the effect of low-dose atropine on binocular vision?

Published:

Research Abstract Summary

Paper title:  Effect of low-dose Atropine on Binocular Vision in Children Aged 6 to 17 Years

Authors:  Rachel Emily Breliant (1), Yi Pang (1), Aliana Bandstra (1), Valerie Kattouf (1)

  1. Illinois College of Optometry, Chicago, Illinois, United States

Date: June 2022

Reference:  Investigative Ophthalmology & Visual Science June 2022, Vol.63, 4317 – A0022. [Link to abstract]

Summary

This study investigated changes in pupil size and binocular vision function from varying concentrations of atropine.

Forty-six children aged between 6 and 17 yrs (mean age 11 yrs) were randomly assigned to either a placebo group or to have one drop of atropine of 0.01%, 0.03% or 0.05% strengths instilled in each eye.

Pupil size in bright and dim light was measured, along with phoria at distance and near, near point of convergence (break and recovery and stamina and fragility) and positive and negative fusional vergence at near. Each measurement was repeated at 30-minute, 60-minute and 24-hour intervals after the drops were administered.

There was no significant difference found for any of the binocular function measurements for the 0.01%, 0.03% or the 0.05% concentrations. However, there were significant differences in pupil sizes for bright and dim lighting for all the strengths compared to the placebo drop at each time interval:

  • All concentrations were found to give the most effect on pupil size after an hour
  • The 0.01% and 0.05% concentrations showed no significant difference from the baseline pupil size after 24 hours
  • The 0.03% strength gave partially recovered pupil sizes after 24 hours with no significant difference from the 30-minute interval, although there was still a significant difference from the baseline.

These results agree with the previous LAMP study which found that 0.05% atropine may reduce amplitude of accommodation by 2D, while 0.01% atropine barely reduced it.1

What does this mean for my practice?

Low-dose atropine between 0.01% and 0.05% is not detrimental to binocular vision function of children aged 6 to 17yrs with myopia. The maximum increase in pupil size is reached one hour after instillation, confirming that nightly dosing before bedtime should lead to minimal impact on visual function.

What do we still need to learn?

This is an abstract only for now and the full study may provide more information on:

  • Why the mid-strength concentration of 0.03% showed partial recovery of pupil size after 24 hours when the weaker 0.01% and the stronger 0.05% showed full recovery after the same time.
  • The ethnicity of the children who participated in the study. Different colour irides may impact on the side effects2

Also, since the time intervals were 30 minutes, 60 minutes and 24 hours, an extra time interval between 60 minutes and 24 hours may show more accurately when the pupil sizes recover.

Abstract

Title:  Effect of low-dose Atropine on Binocular Vision in Children Aged 6 to 17 Years

Authors:  Rachel Emily Breliant, Yi Pang, Aliana Bandstra, Valerie Kattouf

Purpose:  To determine the effect of 0.01%, 0.03%, and 0.05% atropine on pupil size and binocular vision function in children aged 6 to 17 years.

Methods:  Forty-six children (28 girls and 18 boys) aged 6 to 17 years were randomized into 4 groups: placebo (n= 10), 0.01% (n=13), 0.03% (n= 11), or 0.05% (n= 12) atropine. One drop of atropine was administered into each eye once. The following measurements were collected before applying atropine and 30 minutes, 60 minutes, and 24 hours following application of atropine: pupil size in bright and dim illumination, associated phoria by cover test at distance and near, near point of convergence (NPC) break and recovery, 5 times repeat of NPC (stamina), NPC through red and green glasses (fragility), negative fusional vergence at near, and positive fusional vergence at near. Repeated measures ANOVA with post hoc comparison was performed to determine the effect of 0.01%, 0.03%, and 0.05% atropine eye drops on binocular vision measurement at each time point.

Results:  The mean age of participants was 10.73 ±3.01 years. Average spherical equivalence by cycloplegic refraction was -1.70 ± 1.98 D and -1.72 ± 2.10 D, OD and OS respectively. Difference in pupil diameters in bright and dim illumination was statistically significant when comparing all 3 atropine groups to placebo group over time (P< 0.001). Atropine eye drops had the most effect on pupil diameter 60 mins after installation (P<0.001). Pupil diameter was partially recovered at 24 hours with no statistical significance compared to the 30-minute time point (P >0.05), although still significantly different from baseline in the 0.03% atropine group (P=0.002). In the 0.01% and 0.05% atropine groups pupil diameter fully recovered after 24 hours with no significant difference from baseline (Ps>0.05). There was no significant difference in binocular vision measurements including associated phoria, NPC, NPC stamina and fragility, negative fusional vergence, and positive fusional vergence (all Ps >0.05)

Conclusions: Pupil size was significantly enlarged by 0.01%, 0.03%, and 0.05% atropine in both dim and bright illumination with more effect at 60 minutes after application. However, low dose atropine eye drops have no effect on binocular vision measurements. Thus, in respect to binocular vision, it is relatively safe to use low-dose atropine to treat myopia progression in children aged 6 to 17 years.

[Link to abstract]

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About Ailsa

Ailsa Lane is a contact lens optician based in Kent, England. She is currently completing her Advanced Diploma In Contact Lens Practice with Honours, which has ignited her interest and skills in understanding scientific research and finding its translations to clinical practice.

References

  1. Yam JC, Jiang Y, Tang SM et al. Low-Concentration Atropine for Myopia Progression (LAMP) Study: a randomized, double-blinded, placebo-controlled trial of 0.05%, 0.025%, and 0.01% atropine eye drops in myopia control. Ophthalmol 2019; 126:113-24. [Link]
  2. Obianwu HO, Rand MJ. The relationship between the mydriatic action of ephedrine and the colour of the iris. Br J Ophthalmol. 1965 May;49(5):264-70. [Link]