Use of microbubble ultrasound contrast agent to demonstrate the iris valve effect in human eye bank eyes.

Abstract

To demonstrate that the interface between the normal iris and the lens surface functions as a flap valve. Microbubble ultrasound contrast agent was injected into the anterior and posterior chambers of human eye bank eyes and the distribution of contrast imaged with high-frequency ultrasound. Contrast agent did not enter the posterior chamber when injected into the anterior chamber, but contrast agent injected into the posterior chamber easily flowed into the anterior chamber. The iris-lens interface normally functions as a flap valve, preventing retrograde flow from the anterior to the posterior chamber. A temporary increase in anterior chamber pressure thus results in iris concavity in pigmentary dispersion syndrome.