Regarding artificial tears, which statement is accurate?

The assertion that higher demulcent concentration increases viscosity is accurate because it highlights the characteristics and formulation of artificial tears. Demulcents are substances that help to create a protective, lubricating barrier on the ocular surface. When the concentration of these compounds is elevated, the result is a thicker, more viscous solution, which can provide prolonged relief from dryness and enhance the stability of the tear film. This increased viscosity is beneficial for individuals experiencing moderate to severe dry eye symptoms, as it can help to retain moisture on the surface of the eye and reduce the frequency of instillation needed.

In contrast, the other options lack accuracy regarding the nature and function of artificial tears. While some formulations may aim to mimic the composition of natural tears, they do not contain identical components, as natural tears include a unique balance of electrolytes, proteins, and lipids. Furthermore, artificial tears are designed to reduce tear film evaporation, not increase it, by providing a protective layer. Lastly, artificial tears can have a positive effect on ocular surface stress by moisturizing and soothing the eyes, rather than having no effect at all, as they are often specifically formulated to address ocular discomfort.