A CONTACT LENS separates the tear film into pre- and post-lens tear films, which impacts the tear film in numerous ways, influencing the biophysical and biochemical tear film properties (Craig et al, 2013). Contact lens wearers exhibit more ocular symptoms than non-wearers (Craig et al, 2013) and may describe dryness or discomfort with contact lens wear.

Contact lens wettability is often depicted in terms of pre-lens tear film (PLTF) stability (Rabiah, 2019). PLTF may be affected by evaporation and other causes (Rabiah, 2019).

Rewetting drops are often recommended to improve contact lens wettability during lens wear (Willcox et al, 2021). Wearers who report contact lens dryness or discomfort may use artificial tears during lens wear to improve the quality of the tear film (Willcox et al, 2021). Yet, artificial tears tend to have a limited residence time on the surface of the eye or contact lens (Willcox et al, 2013).

A systematic review of 64 randomized controlled trials evaluated artificial tears in individuals who have dry eye to elucidate prescribing choices (Semp et al, 2023). Artificial tears were recommended to improve comfort and lubricate the ocular surface, and for contact lens rehydration (Semp et al, 2023). Additionally, artificial tears may facilitate the removal of contact lenses after hours of lens wear by reducing friction on the cornea (Semp et al, 2023).

Various brands of rewetting drops are approved for use with soft or rigid contact lenses. Several factors can impact the performance of rewetting drops, such as their viscosity, molecular weight, shear strength, and mucoadhesive properties (White et al, 2014). For example, various formulations of artificial tears may have different amounts of molecular weight and concentrations of hyaluronic acid (Aragona et al, 2019). With the different concentrations, the pre-corneal residence time may be varied (Craig et al, 2013).

Rewetting drops have a transient (up to 10 minutes) effect on blinking rates (Craig et al, 2013). The addition of rewetting drops onto the contact lens can transiently increase the post-lens tear film thickness for approximately 10 minutes (Chen et al, 2010).

Different wetting agents interact differently with various contact lens materials. Using a sessile drop method, three artificial tear solutions or saline were evaluated (Iwashita et al, 2021). Contact angles were found to be typically lower for hydrogel contact lenses compared to silicone hydrogel contact lenses (Iwashita et al, 2021). Additionally, a rewetting solution containing 2-methacryloyloxyethyl phosphorylcholine demonstrated a decreased contact angle compared to that of a different rewetting solution containing hyaluronic acid (Iwashita et al, 2021).

The stability of artificial tears and phosphate-buffered saline was evaluated on a customized platform (Tyagi et al, 2012). Artificial tears decelerated drainage, making evaporation the main thinning factor. The authors concluded that protein deposits do not alter the stability of the tear film, but protein deposits augment the wettability of contact lenses (Tyagi et al, 2012).

Alternatively, contact lens care solutions, including wetting agents, may restore habitual blinking frequency for extended time intervals (Willcox et al, 2013). This may be due to parts of the contact lens care solution that is incorporated into a contact lens.

Wearers may use compensating behaviors such as using rewetting drops with their contact lenses; however, 73% of wearers do not plan to inform their contact lens practitioner of these behaviors (Morgan and Sulley, 2023). These wearers may be at risk of contact lens dropout; thus, a practitioner must be proactive to achieve ongoing success (Morgan and Sulley, 2023).

When your next contact lens wearer presents for an evaluation, ask if they are using, or have the desire to use, rewetting drops with their contact lenses­—and offer contact lens and solution alternatives. CLS

References

1. Craig JP, Willcox MD, Argueso P, et al. The TFOS international workshop on contact lens discomfort: report of the contact lens interactions with the tear film subcommittee. Invest Ophthalmol Vis Sci. 2013 Oct 18;54:TFOS123-TFOS156.
2. Tyagi G, Alonso-Caneiro D, Collins M, Read S. Tear film surface quality with rigid and soft contact lenses. Eye Contact Lens. 2012 May;38:171-178.
3. Rabiah NI, Scales CW, Fuller GG. The influence of protein deposition on contact lens tear film stability. Colloids Surf B Biointerfaces. 2019 Aug;180:229-236.
4. Willcox M, Keir N, Maseedupally V, et al. CLEAR - Contact lens wettability, cleaning, disinfection and interactions with tears. Cont Lens Anterior Eye. 2021 Apr;44:157-191.
5. Semp DA, Beeson D, Sheppard AL, Dutta D, Wolffsohn JS. Artificial Tears: A Systematic Review. Clin Optom (Auckl). 2023 Jan 10;15:9-27.
6. White CJ, Thomas CR, Byrne ME. Bringing comfort to the masses: a novel evaluation of comfort agent solution properties. Contact Lens Anterior Eye. 2014 Apr;37:81-91.
7. Aragona P, Simmons PA, Wang H, Wang T. Physicochemical properties of hyaluronic acid-based lubricant eye drops. Transl Vis Sci Technol. 2019 Nov 1;8:2.
8. Snibson GR, Greaves JL, Soper ND, Prydal JI, Wilson CG, Bron AJ. Precorneal residence times of sodium hyaluronate solutions studied by quantitative gamma scintigraphy. Eye (Lond) 1990;4(Pt 4(4)):594–602. https://doi.org/10.1038/eye.1990.83 .
9. Chen Q, Wang J, Tao A, Shen M, Jiao S, Lu F. Ultrahigh-resolution measurement by optical coherence tomography of dynamic tear film changes on contact lenses. Invest Ophthalmol Vis Sci. 2010 Apr;51:1988-1993.
10. Iwashita H, Itokawa T, Suzuki T, Okajima Y, Kakisu K, Hori Y. Evaluation of in vitro wettability of soft contact lenses using tear supplements. Eye Contact Lens. 2020 May 1;47:1-5.
11. Morgan PB, Sulley AL. Challenges to the new soft contact lens wearer and strategies for clinical management. Cont Lens Anterior Eye. 2023 Mar 17:101827.