Effect of Topical Pilocarpine on Choroidal Thickness in Healthy Subjects

Optom Vis Sci. 2020 Jun;97(6):457-461. doi: 10.1097/OPX.0000000000001521.


Significance: This is a proof-of-concept study showing the possibility of pharmacological control for choroidal thickness using pilocarpine as an agent that causes 2 to 5% choroidal thinning in healthy eyes after the instillation.

Purpose: The purpose of this article was to study the effect of instillation of 1% pilocarpine on choroidal thickness in healthy subjects.

Methods: Sixteen healthy individuals (seven males and nine females; mean ± standard deviation age, 25.8 ± 3.3 years) were included. All participants received optical coherence tomography to evaluate subfoveal choroidal thickness (SCT) and choroidal area on cross-sectional scan within 4-mm central area. Axial length was measured using optical biometry. Optical coherence tomography was performed before and after pilocarpine was instilled six times for a 75-minute period in one eye; the fellow eye was used as the control. Subfoveal choroidal thickness and choroidal area were measured by two masked graders in random fashion and averaged for analysis.

Results: After instillation of 1% pilocarpine, percentage SCT change in study and control eye was -3.3 ± 3.8% and 0.4 ± 3.2%, respectively (P = .03). Percentage change choroidal area in study and control eye was -2.3 ± 2.5% and 0.8 ± 3.3%, respectively (P < .001). There was a correlation between percentage SCT change and axial length (r = -0.56, P < .001), as well as between percentage SCT change and baseline SCT (r = 0.72, P < .001).

Conclusions: Instillation of 1% pilocarpine causes a decrease of choroidal thickness, which is more substantial in eyes with short axial length and thick choroid.

MeSH terms

  • Administration, Ophthalmic
  • Adult
  • Choroid / diagnostic imaging
  • Choroid / drug effects*
  • Cross-Sectional Studies
  • Female
  • Healthy Volunteers
  • Humans
  • Male
  • Miotics / administration & dosage*
  • Ophthalmic Solutions
  • Organ Size
  • Pilocarpine / administration & dosage*
  • Tomography, Optical Coherence / methods
  • Young Adult


  • Miotics
  • Ophthalmic Solutions
  • Pilocarpine