Contact lenses are a convenient alternative to glasses, and yes, a lens can fall out. However, with modern soft lenses, this occurrence is uncommon. The design of today’s lenses, coupled with the natural architecture of the eye, works effectively to keep the lens centered and stable. Understanding the factors that disrupt this stability can help wearers minimize the chance of dislodgement.
The Eye’s Natural Retention System
The eye possesses an inherent system designed to keep contact lenses in place. The primary mechanism involves the tear film, a thin layer of fluid covering the corneal surface. This film creates surface tension, allowing the contact lens to adhere to the eye like a gentle suction cup.
The tear film includes a mucin layer that helps the aqueous fluid spread evenly and adhere to the eye’s surface. A contact lens splits this film into pre-lens and post-lens tear films, which lubricate the lens and surrounding ocular tissue. The conjunctiva, a clear membrane lining the inner eyelid and covering the white part of the eye, also plays a protective role. This membrane forms a continuous barrier that physically prevents a contact lens from slipping behind the eye into the orbit.
Common Reasons Contacts Dislodge
While the eye’s anatomy is designed to retain the lens, certain factors can overcome this natural adhesion and cause the lens to dislodge. Dryness, or a lack of adequate tear film, is a frequent culprit, as the lens loses the moist cushion necessary for stable adherence. Environmental factors like wind, air conditioning, or staring at a screen for extended periods can accelerate tear evaporation, weakening the lens’s grip.
An improper lens fit is another significant reason a lens may fall out or shift excessively. If the lens’s base curve is too flat for the curvature of the cornea, the lens will sit loosely and slide around easily, making it prone to dislodgement. Rigid Gas Permeable (RGP) lenses, being smaller and less flexible than soft lenses, are historically more susceptible to popping out because they do not conform to the eye’s shape as closely. Physical action, such as aggressively rubbing the eye or a sudden impact, can also mechanically force a lens out of its centered position.
The intrusion of a foreign object, like dust or an eyelash, can also cause the lens to lift off the cornea and fall out. This debris disrupts the smooth interface between the lens and the eye, leading to irritation and shifting. Soft lenses are less likely to experience foreign body intrusion underneath the lens compared to RGP lenses. Another element is wearing lenses past their recommended replacement schedule, which can lead to deposit buildup. This buildup affects the lens material and contributes to instability and movement.
Prevention and Immediate Steps
Consistency in lens care and wear habits is important to minimize the likelihood of a contact lens falling out. Using rewetting drops formulated for contact lenses can replenish the tear film and counteract dryness. Regularly replacing lenses according to the prescribed schedule helps prevent the buildup of deposits that interfere with proper adhesion. Proper professional fitting ensures the lens base curve and diameter are correctly matched to the eye’s dimensions, which is foundational for stability.
If a lens does fall out, immediate steps are important for eye health. If the lens is found, it should never be reinserted without thorough cleaning and disinfection. The lens must be rinsed with fresh, sterile solution, gently rubbed in the palm with more solution, and then rinsed again to remove contaminants. For reusable lenses, a full disinfection soak for the recommended period, often six to eight hours, is necessary to sterilize the lens.
If the lens is lost but the eye feels irritated, check for the possibility that the lens is folded and lodged under the eyelid. Gently rinsing the eye with saline solution can help dislodge a misplaced lens. If irritation persists, or if the lens cannot be located, consulting an eye care professional is the safest course of action. Daily disposable lenses that fall out should be discarded immediately, as they are not designed to withstand the rigorous cleaning process required for reinsertion.