A Grid Software for Virtual Eye Surgery Based on Globus 4 and gLite

``Grid-Enabled SEE++'' is based on the SEE++ software system for the biomechanical simulation of the human eye. ``Grid-Enabled SEE++'' extends SEE++ in several steps in order to develop an efficient grid-based tool for ``Evidence Based Medicine'', which supports surgeons in choosing optimal surgery techniques for the treatment of certain eye motility disorders. Recently, we refined the design of ``Grid-Enabled SEE++'' and we worked on an extended version of the software, which is able to utilize the ``Web Service Resource Framework'' architecture of the Globus Toolkit 4. Since we met with some limitations of Globus 4, we also designed a version of ``Grid-Enabled SEE++'' compatible with the gLite grid middleware. In this paper, we report on our experience of porting a grid application to Globus 4 and gLite, describe the problems we encountered and discuss possible solution strategies. This may assist the porting of other applications to the grid using these middleware products.