A proof-of-concept study from a team of Russian researchers reports pilocarpine may be able to reduce choroidal thickness by between 2% and 5% in healthy eyes.
The research, published in Optometry and Vision Science, included 16 patients who were about 26 years old and were administered 1% pilocarpine. All participants underwent OCT imaging to evaluate subfoveal choroidal thickness (SCT) and the choroidal area as seen on cross-sectional scans within a 4mm central area. The investigators measured axial length with optical biometry and performed OCT before and after pilocarpine instillation, which was done six times for a 75-minute period in one eye. The fellow eye was used as the control. Two masked graders randomly measured SCT and the choroidal area.
After the instillation of 1% pilocarpine, the SCT change in the study eye and the control eye was -3.3±3.8% and 0.4±3.2%, respectively. Additionally, the change of the choroidal area in the study and the control eye was -2.3±2.5% and 0.8±3.3%, respectively.
The researchers noted a correlation between the percentage SCT change and axial length as well as between the percentage SCT change and baseline SCT.
A decrease in choroidal thickness appeared to be more substantial in eyes with shorter axial lengths and thicker choroids.
Maltsev DS, Kulikov AN, Vasiliev A. Effect of topical pilocarpine on choroidal thickness in healthy subjects. Optometry and Vision Science. June 20, 2020. [Epub ahead of print].