The common discomforts associated with wearing contact lenses, such as dryness, irritation, and grittiness, often prompt wearers to use eye drops. Standard drops are frequently incompatible with contacts and can damage the lens material or trap irritating ingredients against the eye’s surface. Specialized rewetting or lubricating drops are formulated to safely hydrate the lens and ocular surface, providing mid-day relief. Choosing the correct product is paramount, as unsafe formulations can quickly lead to lens clouding, intense irritation, and corneal surface damage.
Rewetting Drops Versus Redness Relief Drops
The primary distinction in over-the-counter eye drops is between rewetting (or lubricating) drops and redness relief drops. Rewetting drops are safe for contacts and are designed to refresh the lens and eye by restoring the tear film, which often becomes unstable during prolonged wear. These drops are formulated to be isotonic with natural tears and contain polymers that coat the lens material without causing structural changes. Their purpose is to lubricate and hydrate the lens and cornea, reducing friction and enhancing comfort.
Conversely, redness relief drops contain vasoconstrictors, such as tetrahydrozoline or naphazoline, which temporarily shrink blood vessels to make the eye appear whiter. These chemicals are highly unsafe for use with contacts because the lens material absorbs and concentrates the chemical. This absorption leads to significant eye irritation, lens discoloration, and potential damage to the corneal epithelium. The temporary whiteness is often followed by rebound hyperemia, where blood vessels dilate beyond their original size, resulting in more pronounced redness. Users should never apply redness relief drops while wearing lenses.
Essential Ingredients and Preservative Considerations
The chemistry of rewetting drops determines their compatibility and effectiveness with contact lenses, focusing heavily on lubricating agents and the preservative system.
Preservative Systems
Traditional, harsh preservatives like Benzalkonium Chloride (BAK) are strongly contraindicated for soft contact lenses because they bind to the lens polymer. High-water content lenses absorb significant BAK, which is continuously released onto the ocular surface, causing toxicity, irritation, and potentially leading to toxic keratitis.
Modern, safer drops utilize gentler preservative systems or compounds with larger molecular sizes that minimize lens absorption. Preservatives like Polyquad (Polyquaternium-1) prevent microbial growth but are too large to be absorbed into the soft lens material, making them less toxic. Other “disappearing” preservatives, such as Purite or stabilized oxychloro complex, break down into natural tear components upon exposure to the ocular surface, eliminating the risk of chemical buildup. The safest option for frequent application or sensitive eyes remains preservative-free drops, which are typically packaged in single-use vials.
Lubricating Agents
The lubricating efficacy of safe drops is provided by high-molecular-weight polymers that mimic the natural tear film. Common and effective lubricating agents include Hyaluronic Acid (often listed as Sodium Hyaluronate), which is excellent at retaining moisture, and polymers like Polyethylene Glycol (PEG) and Carboxymethylcellulose (CMC). These polymers increase the drop’s viscosity, allowing it to coat the lens and eye surface for a longer period to reduce friction. While both PEG and CMC are effective, PEG formulations may provide quicker subjective comfort and are often combined with other protective agents.
Best Practices for Applying Drops While Wearing Contacts
Proper technique and timing are essential for maximizing comfort and maintaining eye health. Before touching the eyes or the drop bottle, thoroughly wash your hands to prevent introducing bacteria. Tilt your head back, gently pull down the lower eyelid to create a small pocket, and squeeze one drop into the pocket. Be careful to avoid touching the dropper tip to your eye or lashes. After instillation, close your eye gently for a few moments to allow the drop to spread evenly across the lens and eye surface.
Vision may be temporarily blurred immediately after application, especially with higher-viscosity drops, so wait a few minutes before driving or performing tasks that require clear eyesight. The best time to apply drops is proactively, before severe dryness sets in, to maintain optimal lens hydration throughout the day. Adhere to the product’s shelf life: most multi-dose bottles should be discarded 30 days after opening, while single-use, preservative-free vials must be discarded immediately after use.