An ICG angiogram-based clinical method for characterizing the choroidal circulation used to assess the hemorrheologic effects of pentoxifylline.

PURPOSE

To demonstrate an indocyanine green (ICG) angiography-based clinical method for characterizing choroidal blood flow and for detecting changes in choroidal circulation patterns, and by use of that method, to demonstrate that pentoxifylline affects choroidal blood flow.

METHODS

High-speed ICG angiography was performed in rhesus monkeys before and after intravenous administration of pentoxifylline or saline (which served as a control) while monitoring blood pressure and heart rate. From these data, three-dimensional surface maps indicating the instantaneous relative distribution of choroidal blood flow during the peak of intra-ocular pressure pulse systole in a 30 degrees field, centered on the macula, were generated to characterize the state of the choroidal circulation at various times during the experiments.

RESULTS

Comparisons of the 3-dimentional surface maps consistently indicated an increase in sub-macular choroidal blood flow occurring within 5 to 10 minutes post-pentoxifylline injection, with a gradual return to baseline level 20-40 minutes later. Injection of equal volumes of saline produced no changes in choroidal blood flow.

CONCLUSIONS

Posterior-pole choroidal blood flow can be characterized as by a three-dimensional surface representing the instantaneous relative distribution of choroidal blood flow during the peak of intra-ocular pressure pulse systole. Pentoxifylline does, at least transiently, increase sub-macular choroidal blood flow.