Contact lenses offer a convenient way to correct vision, but shifting or moving on the eye can be frustrating. While some minimal movement is normal, excessive lens movement can cause discomfort, blurred vision, and constant awareness of the lens. Understanding these reasons helps address the problem effectively. Factors range from lens fit to environmental conditions.
Common Reasons for Lens Movement
Improper fit frequently causes contact lenses to move. Lenses are designed with specific curvatures, including a “base curve” (BC), and a diameter to match the unique shape of an individual’s cornea. If a lens is too loose, its diameter or base curve may be inaccurate, causing it to shift excessively with each blink and potentially feel like it might fall out. Conversely, a lens that fits too tightly can initially feel comfortable but may later cause discomfort, reduced oxygen supply to the cornea, and even lead to blurry vision because it doesn’t move enough to allow for proper tear exchange.
Insufficient tear film or dry eyes contribute to lens instability. Lenses rely on eye moisture to stay hydrated, maintain shape, and adhere comfortably to the ocular surface. When tear production is inadequate, or tear quality is poor, the lens can lose its necessary lubrication, leading to increased friction and excessive movement. Factors like extended digital device use, which reduces blink rates, or environmental conditions such as air conditioning or wind can exacerbate dry eye symptoms, making lenses feel rough or uncomfortable and prone to shifting.
Foreign bodies or debris also cause lens displacement. Tiny particles like dust, lint, or makeup can get trapped between the lens and eye. This debris acts as an irritant, causing the eye to try and flush it out, which can push the lens out of place. Protein deposits from tears can also accumulate on the lens surface over time, creating a gritty sensation and making the lens feel loose and unstable.
Improper handling or insertion techniques cause lens movement. Placing a lens inside out, or failing to ensure it settles properly on the cornea without trapped air bubbles, can prevent it from adhering correctly. Allergies or eye irritation also affect lens stability. Conditions like giant papillary conjunctivitis (GPC), often linked to contact lens wear, involve inflammation and bumps on the inner eyelid that can cause increased lens movement and discomfort.
The material and design of the lens itself influence movement. Lens properties like diameter, thickness, and water content influence how much a lens moves. For example, lenses with a higher modulus, or stiffness, might provide insufficient movement, while those with a lower modulus might be harder to handle. Proper lens movement is necessary for oxygen supply to the cornea and flushing out debris, making lens design a factor in comfort and stability.
Corrective Measures and Solutions
Maintaining proper lens care and hygiene is important in preventing lens movement. Always wash and dry hands thoroughly with a lint-free towel before handling lenses to avoid introducing debris. Adhering to the recommended cleaning, storage, and replacement schedules helps prevent protein and lipid deposits from accumulating, which can otherwise affect lens comfort and stability.
Using re-wetting drops alleviates dryness and improves lens comfort and stability. These drops help replenish the tear film, providing lubrication for the lens to sit properly. Regular use of re-wetting drops, as recommended by an eye care professional, can counteract the drying effects of environmental factors and prolonged lens wear.
Ensuring proper insertion techniques prevents initial lens instability. Before insertion, verify the lens is not inside out by checking if its edges form a smooth “bowl” shape rather than flaring outwards. When placing the lens, gently hold your eyelids open and position the lens directly on the cornea, then blink slowly to allow it to settle. If the lens feels uncomfortable or moves immediately after insertion, remove, rinse, and reinsert it.
Addressing environmental factors mitigates lens movement. In dry or windy conditions, wearing protective eyewear like glasses or sunglasses shields eyes from irritants and reduces tear evaporation. If spending extended periods in air-conditioned or heated environments, consciously increasing your blink rate can help distribute tears more evenly across the eye surface.
When a lens becomes displaced during wear, temporary removal and reinsertion can resolve the issue. Always wash hands before touching eyes or lenses. Gently remove the lens, rinse it with fresh contact lens solution, check for damage or debris, then reinsert carefully. This process can help clear any trapped particles and re-center the lens.
When Professional Guidance is Needed
While many instances of contact lens movement resolve with self-care, persistent or frequent lens shifting requires professional evaluation. If the problem continues despite trying corrective measures, an eye care professional can assess the lens fit to determine if it is too loose or too tight. An improper fit can lead to ongoing discomfort, blurred vision, or even potential corneal damage over time.
Seek professional guidance if lens movement is accompanied by discomfort, redness, or pain. These symptoms can indicate irritation, inflammation, or a more serious underlying issue. Persistent eye redness, a gritty sensation, or pain that does not improve after removing the lenses are warning signs that require prompt attention.
Blurred vision or vision changes with lens movement suggest professional assessment. This could indicate an outdated prescription, a lens that no longer fits correctly, or other ocular conditions.
Signs of a suspected eye infection, such as discharge, increased light sensitivity, or a foreign body sensation, require urgent professional evaluation. Untreated infections can lead to severe complications, including corneal ulcers or vision loss.
An eye care professional can perform a comprehensive eye exam to assess eye health, measure corneal curvature, and recommend refitting or a lens type change. They can also diagnose underlying eye conditions like giant papillary conjunctivitis (GPC) which may be contributing to lens movement and require specific treatment.