Abstract
Purpose :
The purpose was to objectively study how OVD intramolecular cohesion contributes to restoring anterior depth volume and the OVD removal properties after IOL implantation. In addition, the study compares how intramolecular cohesion predicts the OVD functional performance compared to the conventionally used viscosity parameters, such as zero shear.
Methods :
Sodium hyaluronate (HA) dissolutions of different molecular weights and concentrations were evaluated. A Bohlin Rheometer was used to evaluate rheology, including rotational and oscillatory measurements. Tackiness testing and a specially designed test cell were used for cohesiveness classification. The anterior chamber depth maintenance and removal properties were quantitatively evaluated during simulated surgery in cadaver pig eyes by Scheimpflug technique, and related back to the molecular cohesion of the OVD.
Results :
The cohesiveness of the OVD is related to the molecular weight and concentration of the sodium hyaluronate. Scheimpflug studies show that a higher cohesiveness relates positively to anterior chamber depth maintenance and removal properties. At a certain concentration of HA (18-20 mg/ml for high molecular weight HA) the OVD characteristic becomes viscoadaptive, which requires a changed irrigation/aspiration technique for optimal removal. In this study, the intramolecular cohesion measurements better predicts OVD functional performance for anterior chamber depth maintenance and removal properties compared to conventional viscosity parameters.
Conclusions :
Cohesiveness classification, together with rotational and oscillatory data can predict the OVD performance related to anterior chamber depth maintenance and removal properties and should be utilized together with zero shear data when comparing functional performance of OVDs.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.