In Virtual Environments (VE), users are often facing tasks that involve direct manipulation of virtual objects at close distances, such as touching, grabbing, placement. In immersive systems that employ head-mounted displays these tasks could be quite challenging, due to lack of convergence of virtual cameras. We present a mechanism that dynamically converges left and right cameras on target objects in VE. This mechanism simulates the natural process that takes place in real life automatically. As a result, the rendering system maintains optimal conditions for stereoscopic viewing of target objects at varying depths, in real time. Building on our previous work, which introduced the eye convergence algorithm [Sherstyuk and State 2010], we developed a Virtual Reality (VR) system and conducted an experimental study on effects of eye convergence in immersive VE. This paper gives the full description of the system, the study design and a detailed analysis of the results obtained. CR Catego...