Physicochemical Properties of Ophthalmic Viscosurgical Devices

Due to immense product diversity, ophthalmic surgeons rely largely on manufacturers reports of physicochemical viscoelastic specifications and on company recommendations in their selection of a suitable agent. Manufacturer information is based on substance testing conducted by different institutes and sometimes reveals inconsistencies. The physicochemical characteristics must fulfill practical criteria which are essential for every-day operative use  

We have attempted to reveal the actual conditions by running our own set of comparative tests in cooperation with the Max-Planck Institute for Polymer Research, Department of Rheology, Mainz, Germany. 

Rheology is the study of the relationship between substance deformation and the forces generated by it. Ophthalmic viscosurgical devices (OVD) have both fluid and solid properties. Each substance has a specific distribution of physicochemical characteristics which define its clinical application. 

Understanding this relationship allows us to select a specific substance to maintain the anterior chamber space, protect the corneal endothelium or coat instruments and tissues. 

To understand the mode of action of viscoelastic substance in ocular surgery, the following determinants are particularly important viscosity, elasticity, viscoelasticity, pseudoplasticity and coatability. 

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