The effect of nicotine on choroidal thickness

Purpose To investigate the effect of nicotine on choroidal thickness using optical coherence tomography (OCT). Design Prospective, case-control study. Methods Sixteen young, healthy subjects and 16 age and gender matched control cases were included in this study; 4 mg nicotine gum was given to the study group and placebo gum to the control group. All participants underwent OCT scanning with a high-speed and resolution spectral-domain OCT device (3D OCT 2000, Topcon, Japan) at baseline, and 1 h following nicotine or placebo administration. The measurements were taken in the morning (10:00-12:00 hours) to avoid diurnal fluctuation. Results The median foveal choroidal thickness at baseline was 337.00 mu m (IQR 84.50), which decreased to 311.00 mu m (IQR 78.00) at 1 h following oral nicotine intake (p=0.001). The median choroidal thickness was also significantly decreased at five other extrafoveal points (p<0.05 for all). In the control group, the median baseline choroidal thickness at the fovea was 330.50 mu m (IQR 104.25), and was 332.00 mu m (IQR 103.75) at 1 h (p=0.271). Conclusions Nicotine causes a significant decrease in choroidal thickness following oral intake. This acute decrease might be a result of reduced ocular blood flow due to the vasoconstrictive effect of nicotine.