Digital Ultrasound And Optical Coherence Tomography-guided Measurement Of Choroidal Perfusion And Thickness Following Systemic Sildenafil

Abstract

 

Purpose:

 

To demonstrate anatomic and flow changes in the human choroid following systemic sildenafil citrate (Viagra®) using enhanced depth imaging spectral domain-optical coherence tomography (EDI-OCT) and swept-scan high frequency digital ultrasound.

 

Methods:

 

Seven healthy male subjects (mean age 32.7 years) were evaluated at baseline and two hours after ingesting 50 mg of sildenafil. Choroidal perfusion measurements were made using swept-scan high frequency digital ultrasound. Choroidal thickness measurements were made using EDI-OCT. Results were read by masked observers. One patient underwent fluorescein angiography. The Wilcoxon signed-rank test and paired t-test were used to analyze differences in choroidal flow and thickness at baseline and two hours after ingestion of sildenafil.

 

Results:

 

Two hours following sildenafil, increased choroidal perfusion was observed in 11 of 12 eyes measured by swept-scan high frequency digital ultrasound (Figures A-D). The mean increase was 3.46 (±2.00) times baseline with a range of 0.47 to 7.80 times baseline (p=0.004). Choroidal thickness measured with EDI-OCT showed increased thickness for all eyes (Figures E-F). The average choroidal thickness for all eyes increased by 11.6% temporal to the fovea, 9.3% nasal to the fovea, and 10.7% underneath the fovea (p<0.001 for all values). Fluorescein angiography showed no significant variation in fill time or vessel caliber.

 

Conclusions:

 

This study demonstrates an increase in choroidal perfusion and thickness in response to sildenafil. These changes could secondarily affect retinal function, explain previously reported clinical symptoms, and potentially be a useful adjunct for treatment of ocular diseases that would benefit from increased choroidal blood flow.  

 

Keywords: choroid • imaging/image analysis: clinical • blood supply