Abstract
Purpose :
To ascertain whether the molecular weight of sodium hyaluronate in artificial tears, affects its clinical efficacy
Methods :
The rheology of HydraMed, Evolve and Hylo-Forte eye drops, which all contain 0.2% hyaluronic acid as the principal component, was assessed using a research rheometer fitted with a 60mm aluminium flat plate measuring system at 31°C. Shear rate profiling was performed on each artificial tear. A total of 25 participants diagnosed with dry eye disease (TFOS DEWS II criteria), aged 23.6±9.2 years, were randomly allocated to receive each drop, on different days. Comfort, non-invasive breakup time, tear meniscus height and ocular redness was assessed at baseline and then 5, 15, 30, 45, 60 and 90 minutes after application.
Results :
Hylo-Forte showed a more non-Newtonian relationship between viscosity and sheer force (r2=0.295) compared to HydraMed (r2=0.485) and Evolve (r2=0.521). Comfort and tear stability improved with drop instillation (p>0.05), declining with time (p<0.001), with all drops following a similar profile (p>0.05). Hylo-Forte demonstrated the highest comfort and tear stability retention effect. Tear volume increased with drop instillation and then declined with time (F=18.643, p<0.001). Evolve had a reduced initial effect compared to HydraMed and Hylo-Forte (F=4.045, p<0.001). Average bulbar redness was low (0.63±0.44 Efron grade) and did not change with drop application (F=1.721, p=0.120).
Conclusions :
The molecular weight and rheology of sodium hyaluronate in artificial tears leads to differences in clinical effectiveness. The intra-blink viscosity reduces (which may reduce frictional effects) compared to the inter-blink viscosity, increasing in-eye retention and comfort.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.