Hyaluronic acid concentration predictably modulates physicochemical properties and clinical performance in ophthalmic viscosurgical devices: integrated laboratory and prospective clinical assessment

Background Ophthalmic viscosurgical devices (OVDs) are essential in cataract surgery for maintaining anterior chamber stability and protecting intraocular tissues. This study evaluated the physicochemical and rheological properties of three hyaluronic acid–based OVDs (OpHLINE ® 1.4%, 2%, and 3%) and assessed their clinical performance. Methods A two-phase investigation was conducted: (1) characterization of OpHLINE formulations versus four commercial comparators, including cohesive–dispersive analysis and viscosity–shear profiling; and (2) a prospective clinical trial in 68 patients undergoing phacoemulsification with intraocular lens implantation. Primary endpoint was workspace maintenance; secondary endpoints included ease of OVD removal, endothelial cell density (ECD) loss, and intraocular pressure (IOP) changes. Results By varying HA concentration at constant molecular weight, we achieved direct control of rheological properties and CDI, generating distinct functional profiles: OpHLINE 1.4% behaved cohesively with rapid aspiration, OpHLINE 3% exhibited dispersive-like retention while maintaining space, and OpHLINE 2% combined cohesive handling with the highest shear-resistant viscosity. Clinically, OpHLINE 2% maintained an intermediate behaviour regarding space maintenance, ease of removal, ECD and IOP, while OpHLINE 3% provided the highest full chamber maintenance during all surgical steps. OpHLINE 1.4% enabled the easiest removal (95% adequate) and the lowest ECD loss (12.9%). IOP spikes ≥ 30 mmHg occurred in 13.6%, 20.8%, and 30.4% of eyes at 6 h for 1.4%, 2%, and 3%, respectively, resolving without sequelae. Conclusion This study demonstrates that cohesive–dispersive behaviour and shear-dependent viscosity can be predictably tuned by HA concentration alone, enabling a modular, evidence-based approach to OVD selection. OpHLINE series provide evidence for three distinct behaviours: 1.4% showed optimal removal and endothelial protection; 2% offered balanced rheological and clinical properties; 3% provided the most consistent anterior chamber stability during surgery. These results allow surgeons to tailor intraoperative performance without altering polymer chain length. Trial registration This study was retrospectively registered (OpHLINE-PIC01-2020), approved on 8 February 2021 by the Ethics Committee for Research with Medicines of Euskadi (CEIm-E, Spain, code PS2020065). Trial Registration: ClinicalTrials.gov, NCT ID Number NCT07343973, Registered on 07 January 2026.