Effects of atropine on the accommodative system: parameters to consider in its use for penalization treatment of amblyopia.

Purpose: We set out to determine the accommodative effects of Atropine on the visual system.

Methods: A prospective study was done on a normal eye in a 31-year-old cooperative adult. One drop of 1% Atropine was instilled and the effect on accommodation, near visual acuity and pupil size was recorded. Accommodation was measured at 1/3 of a meter utilizing the Grand Seiko Auto Refractor. Near visual acuity was measured with the PEDIG ATS 4 near visual acuity test at a set distance of 16 inches.

Results: Atropine caused its greatest effect to accommodation, and to pupil size, 3 hours after installation. Curiously, the greatest effect on near visual acuity was seen 27 hours after instillation at which time it dropped to 20/80. Near visual acuity had improved to 20/25 on day 4. Accommodation returned to normal 8 days after instillation and pupil size returned to normal 12 days after instillation.

Conclusion: One drop of Atropine affected accommodation for 8 days. Despite this, near vision returned to 20/20 by day 5. These findings may impact how Atropine penalization is prescribed to treat amblyopia both to maximize effectiveness and minimize its impact on school performance.