Wearing contact lenses every day is a widely accepted and safe method of vision correction. Daily use is generally safe when users adhere to established protocols for wear and care. However, contact lenses are medical devices placed directly on the eye’s surface. Ignoring the prescribed wearing schedule or neglecting proper hygiene significantly elevates the risk of serious complications that can threaten ocular health.
How Daily Contact Lens Wear Affects Eye Physiology
The primary challenge of wearing contact lenses daily is managing the eye’s need for oxygen and maintaining a stable tear film. The cornea is unique because it lacks blood vessels and must draw oxygen directly from the air through the tear layer. When a contact lens covers the cornea, it acts as a physical barrier that reduces oxygen availability. This reduced oxygen can lead to corneal hypoxia, potentially causing epithelial thinning or mild corneal swelling.
Modern contact lenses, particularly those made from silicone hydrogel materials, are designed for high oxygen transmissibility to minimize this effect. Even with advanced materials, the lens disrupts the natural tear film, which lubricates and nourishes the eye. The lens accelerates tear evaporation and reduces the overall volume of tears on the ocular surface. A compromised tear film can lead to discomfort, dryness, and a greater susceptibility to mechanical irritation and infection.
Recognizing Common Complications and Risks
Consistent daily wear, especially when not managed properly, can lead to several specific negative outcomes. The most immediate and sight-threatening risk is microbial keratitis, an infection of the cornea. This condition is often caused by bacteria, such as Pseudomonas aeruginosa, but can also involve fungi or the parasite Acanthamoeba. The risk is significantly higher for contact lens wearers, and it can rapidly progress, leading to severe vision loss or requiring emergency corneal transplantation.
Beyond infection, the eye may develop non-infectious mechanical and physiological issues. One example is corneal neovascularization, where new blood vessels grow into the normally clear corneal tissue. This is a response to chronic oxygen deprivation from long-term lens wear, and these vessels can permanently obstruct vision. Mechanical trauma from the lens rubbing against the eye or the eyelid can also cause corneal epithelial abrasions.
Inflammatory and allergic reactions also frequently occur with daily lens use. Giant Papillary Conjunctivitis (GPC) is a common inflammatory response characterized by the formation of tiny bumps on the inner surface of the upper eyelid. GPC is often triggered by the buildup of protein deposits on the lens surface or chronic friction. Symptoms include increased mucus production, foreign body sensation, and significant itching, often leading to lens intolerance.
Essential Guidelines for Maintaining Ocular Health
Mitigating the risks of daily contact lens wear depends on strict adherence to preventative actions. Proper hygiene begins with washing and thoroughly drying hands with a lint-free towel before touching the lenses or eyes. For reusable lenses, the “rub and rinse” method is critical, where the lens is physically rubbed with fresh solution for a few seconds before rinsing.
It is imperative to use only fresh, unexpired disinfecting solution each time the lenses are stored, and never to “top off” old solution in the case. Lenses should never be exposed to tap water, saliva, or any non-sterile liquid, as these contain microorganisms, including Acanthamoeba, that can cause severe infections. The lens storage case must be cleaned after each use, allowed to air dry, and replaced at least every three months to prevent bacterial accumulation.
Adherence to the prescribed replacement schedule is non-negotiable for ocular health. Daily disposable lenses, for instance, are designed for a single use and must be discarded after removal, as reusing them significantly increases infection risk. Unless approved for extended wear, all contact lenses must be removed before sleep to allow the cornea to receive adequate oxygen. Regular, comprehensive eye examinations are necessary to monitor corneal health and ensure the lens prescription and fit remain appropriate for the eye’s changing physiology.