[Clinical Functionality of Dispersive OVDs: Improvement of One of the Properties of 3% Hyaluronic Acid and 4% Chondroitin Sulfate Combination].

Ophthalmic viscosurgical devices (OVDs) are mainly divided into two general categories: cohesive and dispersive. Dispersive OVDs such as the 3% hyaluronic acid and 4% chondroitin sulfate (HA/CS) combination have excellent adhesion to ocular tissues and protect the corneal endothelium to a greater extent than cohesive OVDs. Herein, we summarize our recent findings regarding one of the properties of the HA/CS combination related to clinical performance. (i) The room temperature stability of OVDs and needle clogging by OVDs remain clinical issues. We demonstrated that adding d-sorbitol to the HA/CS combination preserved its viscosity, which was equivalent after 2 year-storage at room temperature to the viscosity of HA/CS combination stored under refrigeration for 2 years without d-sorbitol. Besides, the HA/CS combination with d-sorbitol could be used repeatedly without cleaning or replacing the needle, suggesting that the addition of d-sorbitol prevents drying and solidification of the OVD on the needle. (ii) Although it can be inferred from numerous studies that the tissue adhesion of OVDs influences their retention by the eye, little is known about the physical properties of OVDs that contribute to intraocular retention. To address this issue, we compared two types of adhesive forces, detachment force and repulsive force, for each OVD. Compared with other dispersive OVDs, the HA/CS combination showed higher values for both adhesive forces. These results suggest that adhesive forces may be used as an index of dispersive OVD retention in the eye.