What risk is associated with continuous wear contact lenses?

Continuous wear contact lenses are designed to be worn for extended periods, even overnight. One of the primary risks associated with this practice is oxygen deprivation to the cornea. The cornea requires a significant amount of oxygen to maintain its health, and when contact lenses are worn continuously, particularly those that are not designed to allow high levels of oxygen permeability, this can lead to hypoxia, or a lack of oxygen reaching the cornea. Hypoxia can cause various complications, including corneal swelling, redness, discomfort, and even more serious conditions like corneal neovascularization or infections.

The other options contrast with this risk: increased tear film stability, limited lens deposits, and improved comfort during sleep would not typically be associated with continuous wear lenses. While some patients may experience comfort and cleanliness with proper hygiene, the overriding concern with extended wear is ensuring adequate oxygen is supplied to the cornea, hence making oxygen deprivation a significant risk factor when using these lenses.