Evaluation of Rheological Properties of Cohesive Ophthalmic Viscosurgical Devices Composed of Sodium Hyaluronate with High Molecular Weight—2019

Abstract

Ophthalmic viscosurgical devices (OVDs), mainly containing sodium hyaluronate (HA), are used in cataract surgeries to protect the cornea endothelium. In this study, the rheological properties of 9 launched products (containing 1％ HA) were evaluated. The molecular weights (MWs) of HA estimated based on intrinsic viscosity varied widely, between 1100 2500 kDa, and showed a particular value for each product. Of the 9 products, 6 are classiˆed as cohesive OVDs and their product speciˆcations show the same value for intrinsic viscosity (25 45 dL/g), with high MW HA (＞ 2000 kDa); however, the MW of each HA showed a particular value (2200 2500 kDa) within the range of the product speciˆcation. As with the MW of HA, apparent viscosity and dynamic rheological parameters showed particular values for each OVD. The product Opegan-Hi exhibited the highest value of apparent viscosity at low shear rate, and a solid-like behavior among the OVDs. In a questionnaire survey among 198 cataract surgeons, 42％ of surgeons had experienced a diŠerence in ability to maintain the depth of anterior chamber during surgery among the diŠerent cohesive OVDs used. This suggested that surgeons select OVD properties based on surgical procedure and patient cases. In conclusion, we demonstrated that each OVD has particular rheological properties within the range of the product speciˆcation deˆned by the intrinsic viscosity. The results might provide useful information for surgeons in their selection of OVDs based on their experience.

Quantitative Assessment of Ophthalmic Viscosurgical Devices on Visibility, Spreadability, and Durability as Corneal Wetting Agents for the Wet Shell Technique

“…We previously reported that the OVDs tested in this study had specific rheological properties even when they were of the same composition or classification type [14,15]. Here, we clarified the advantages and disadvantages of each OVD for the wet shell technique on the basis of their properties.…”

“…In this study, Opelead, Viscoat, and Shellgan were classified into such a category ( Table 2). We previously evaluated the physical properties of these OVD products and demonstrated that their basic properties were different even though they belonged to the same category [14,15]. We have speculated that the molecular weight (Mw) and concentration of HA, which is the main component of OVDs, have a great influence on rheological properties.…”

“… Molecular weights (Mw) of HA and chondroitin sulfate (CS) and apparent viscosity of OVDs at shear rate 1 (1/s) have already been determined [ 14 , 15 ] …”

Ophthalmic Viscosurgical Devices (OVDs) in Challenging Cases: a Review

“…This is measured in the ease of injection of the material and is crucial for the mobilizing effects of OVDs during surgery. It is important to note that the viscosity of an OVD is higher when the molecular weight at low shear rate increases [ 17 ]. Viscoelasticity: it describes the elastic component of the OVD.…”

Advances in Understanding the Mechanism of Ophthalmic Viscosurgical Device Retention in the Anterior Chamber or on the Corneal Surface during Ocular Surgery

“…[8][9][10] Ophthalmic researchers have concluded that retention durability is one of the important properties of OVDs during ocular surgery not only in the intraocular space but also on the ocular surface. [9][10][11][12][13] Previously, we have demonstrated that OVD products have their own rheological properties, even if their product specifications are the same value. 14,15) We have considered that rheological properties, which are not estimated so far, might also influence the retention durability of OVDs not only on the corneal surface but also in the eye.…”