In some cases, the investigators saw pulsatile angiographic aqueous flow. Also, as a novel finding, if images were obtained one location over a longer period of time, they could observe dynamic changes. In areas in which there was no initial angiographic signal, a signal sometimes developed and vice versa, i.e., in areas in which there was a signal initially the signal intensity could be lost.
The results obtained by aqueous angiography were compatible with the findings on anterior-segment OCT and cSLO-IR, validating the signal as representing aqueous humor outflow.
The investigators pointed that the study had some limitations in that the anesthesia could have influenced aqueous humor outflow, the pupillary dilation resulted in changes in the trabecular meshwork as the result of the parasympathetic blockade, and the required use of a lid speculum might have affected the ocular surface pressure.
The investigators plan to test the use of fluorescein in addition to ICG in the future as well as study the cause of pulsatile flow, such as the cardiac cycle, and quantify the dynamic changes.
“Aqueous angiography is possible in eyes of living human subjects and compatible with successful phacoemulsification without surgical complications,” Dr. Huang concluded. “Segmental aqueous outflow was observed as in the enucleated eyes and the living eyes of hon-human primates. Real-time aqueous humor outflow may improve basic knowledge of outflow biology as well as potentially guide glaucoma therapeutics.”