Evaluation of the Lubricating Effect of Hyaluronic Acid on Contact Lenses Using a Pendulum-Type Friction Tester Under Mimicking Physiological Conditions

Abstract

To evaluate the lubricating effect of hyaluronic acid (HA) on soft contact lenses (SCLs) measured using a pendulum-type friction tester. Methods: We measured the coefficient of friction (CoF) of narafilcon A, delefilcon A, and etafilcon A with polyvinylpyrrolidone (PVP), daily disposable SCL material, using a modified pendulum-type friction tester. Sample SCLs were set on an acrylic plastic half-ball and placed into the polyethylene terephthalate hemisphere cup filled with 0.4 mL of test lubricants that included saline and 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% (wt/vol) HA (molecular weight, 850 kDa). The viscosities of saline and HA were measured using an Ubbelohde viscometer. Results: The CoF of the SCL under a low concentration (0.05%) of HA was the lowest and significantly lower than saline in narafilcon A and delefilcon A (P,0.05, Steel multiple comparison test). Under higher HA concentrations (0.3%, 0.4%, and 0.5%), the CoF was significantly higher than that of saline (P,0.01, Steel' multiple comparison test) in all three SCLs. There were no significant differences of CoF among three SCLs in saline and all concentrations of HA. The HA viscosities increased exponentially with the concentration (Y¼1.2829e 9.286X ). Conclusion:The viscosity of a high concentration of HA may increase the friction of SCLs, which may have a deleterious effect on the ocular surface.

Improvement of Soft Contact Lens Wettability After the Instillation of Hyaluronic Acid Eye Drops

“…Aligned with this, they also showed that concentrations of hyaluronic acid at 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% increased the coefficient of friction of the same contact lenses, directly related to the concentration. 21 These contradictory results compared with this study would manifest the need to extrapolate these types of studies to clinical research, evaluating a wide range of contact lens materials, but also better methods to assess in vivo wettability. In addition, using a low concentration of hyaluronic acid (0.005%), Yamasaki et al 22 neither reported an effect on the in vitro wettability of another four different soft contact lenses.…”

In Vitro Evaluation of Soft Contact Lens Wettability With a Nonmodified Commercial Videokeratoscope

“…Iwashita et al 15 also observed that 0.1% HA increased the contact angle (measured by the sessile drop technique) in the same contact lenses compared with the saline solution. 13 In contrast to the finding of the current study, the results of Iwashita et al 13,15 were not consistent with the idea that HA might produce a wetter surface by decreasing both the coefficient of friction and the contact angle. Iwashita et al 15 suggested that these contradictory results could be because of the effect of the viscosity of HA, which has a high molecular weight and behaves as a non-Newtonian fluid.…”

“…For example, Iwashita et al 15 reported that the coefficient of friction of four types of soft contact lenses increased with the concentration of HA (0.1%-0.5%). Iwashita et al 15 also observed that 0.1% HA increased the contact angle (measured by the sessile drop technique) in the same contact lenses compared with the saline solution. 13 In contrast to the finding of the current study, the results of Iwashita et al 13,15 were not consistent with the idea that HA might produce a wetter surface by decreasing both the coefficient of friction and the contact angle.…”

“…Recent studies demonstrated the capability of this molecule to improve soft contact lens wettability both in vivo 12 and in vitro. [13][14][15][16] The measurement of in vitro wettability is a useful method to justify the wetting properties of contact lens products from a regulatory viewpoint 17 or being used in quality assurance procedures. Several in vitro techniques are available to assess contact lens wettability, including the traditional sessile drop technique that measures the contact angle between the liquid and contact lens surface.…”

Prospective bacterial and fungal sources of hyaluronic acid: A review

“…Dry eye syndrome is characterized by a loss of tear film homeostasis and ocular surface inflammation [72] . Due to high mucoadhesion, HW HA is efficient in precorneal water retention and protection of the ocular surface [73] . Meta-analyses have shown no clinical difference in the application of HA-based versus non-HA-based medications [74] but other medical studies, nevertheless, report that a HW HA lacrimal substitute has the potential to become an alternative to autologous serum eye drops in the treatment of dry eye syndrome [59] , [75] , [76] .…”