Which aftercare instruction is critical for maintaining eyelash extensions?

The importance of not using oil-based products in the aftercare of eyelash extensions cannot be overstated. Oil can break down the adhesive that bonds the extensions to natural lashes, leading to premature loss of the extensions. This is particularly significant because the longevity and appearance of eyelash extensions rely heavily on how well they are maintained after the initial application.

When oil-based products are used, such as certain makeup removers, cleansers, or facial moisturizers, they can weaken the bond, making the extensions fall off more quickly and potentially causing irritation to the natural lashes. Therefore, advising clients to avoid oil-based products is crucial for preserving the integrity of the eyelash extensions and ensuring they last as long as possible, which is essential for a successful aftercare routine.

The other options, while they might involve considerations for general eye care, do not specifically address the primary concern of maintaining the bond of eyelash extensions in the same way.