Accommodative microfluctuations and iris contour.

Mechanical interaction between aqueous humor, iris, and intraocular structures can alter the iris profile from its normal curvature. In particular, significant changes to the iris profile occur during accommodation as the anterior lens movement forces the iris into greater posterior bowing. We extended a previous mathematical model of the anterior segment and investigated the response of this coupled fluid-solid system due to accommodative microfluctuations. The results showed that the system response exhibited the same waveform as the stimulus for small-amplitude microfluctuations generally associated with the high-frequency component. Low-frequency microfluctuations with relatively larger amplitudes elicited a response different from the stimulus, indicating that the forces generated by the lens movement significantly affected the aqueous-iris mechanical interaction.