First Author: Y.Kaji JAPAN
Co Author(s): J. Sakakibara M. Yamashita T. Kobayashi T. Oshika
Purpose:
Hydrodynamic analysis of irrigation fluid in the anterior chamber is essential for evaluating safety and efficacy during phacoemulsification. However, the hydrodynamic analysis of irrigation fluid is difficult because the movement of irrigation fluid is 3-dimensional and complex. To resolve the problem, we have attempted to analyze the irrigation fluid flow in the anterior chamber by stereo-particle image velocimetry. This method enables visualization of the direction and calculation of the velocity of irrigation fluid flow by analyzing pairs of images of small particles captured at short intervals. In addition, we evaluated the effect of irrigation fluid on the corneal endothelium by calculating the shear stress.
Setting:
Department of Ophthalmology Institute of Clinical Medicine University of Tsukuba.
Methods:
Porcine eyes were fixed in a glass chamber filled with balanced salt solution. An ultrasound hand piece was fixed to the glass chamber and its tip was inserted into the anterior chamber. Irrigation fluid was mixed with fluorescein-labeled liposomes as tracer particles. During phacoemulsification without ultrasound, a sheet-like Nd-YAG pulsed laser beam was emitted and moved from the iris plane to the top of the cornea continuously. The images of the illuminated liposomes were captured with two CCD cameras positioned with optical axis angle of 70 degrees. Finally, the direction and the velocity of the irrigation fluid and the shear stress on the corneal endothelial layer were calculated.
Results:
We can visualize the 3-dimensional distribution of the movement of irrigation flow in the anterior chamber during phacoemulsification. We can calculate the velocity and direction of the irrigation flow at any point of the anterior chamber. Using the setting of 30 cc/min of flow rate, the maximum velocity was 290 +/- 82 mm/sec. The maximum viscous shear stress was 0.26 +/- 0.19 Pa.
Conclusions:
Particle image velocimetry enabled the visualization of irrigation fluid flow and quantification of its velocity distribution in different planes of the anterior chamber during cataract surgery. In addition, our previous study has shown that shear stress more than 0.3 Pa has the risk of corneal endothelial cell loss. Based on the results of our study, we will evaluate the safety and efficacy of new surgical settings and devices during phacoemulsification to minimize the corneal endothelial cell loss during phacoemulsification. FINANCIAL DISCLOSURE?: No
Please wait while information is loading.
