Objective To improve an experimental system and further study the passive deformation of iris tissue and the extent of anterior chamber angle closure. Methods First we obtained the continuous pressure data and corresponding 2D image of iris from two cameras without destroying orbicular structure and activity of iris. Then we computed the 3D data of rabbit iris based on stereo vision. After that, we calculated two parameters, one was the slope of tangent line of the curves of passive iris deformation, and another was the curvature radius of the maximal passive iris deformation. And finally we scaled the extent of angle closure. Results Experimental results proved that the slope increased from 0.29 to 0.55 and the curvature radius remarkably decreased from 16.13 to 6.67 when the range of pressure difference was from 50Pa to 200Pa. The slope increased from 0.55 to 0.76 and the curvature radius tardily decreased from 6.67 to 4.25 when the range of pressure difference is from 50Pa to 200Pa. Moreover, experimental research also show that anterior chamber angle changes rapidly from about 30° to 15° when pressure difference increases from 50Pa to 200Pa. When the pressure difference increased from 200Pa to 600Pa, anterior chamber angle changed tardily from about 15°to less than 10°. Conclusion This research suggests a reliable theoretical and experimental method for quantification of passive iris deformation and extent of anterior chamber angle closure. The experimental results could be testified by clinical observation and previous researches.