The experience of your eyes feeling like they are “rejecting” a contact lens is medically known as contact lens intolerance. This is a common reason people discontinue lens wear. Intolerance manifests as acute discomfort, chronic irritation, persistent redness, blurred vision, or the inability to keep the lens on the eye comfortably. While the sensation can be alarming, it is rarely a sign that the body is truly rejecting the lens material itself. The issue almost always stems from improper usage, a poor lens fit, environmental factors, or an underlying, treatable eye condition aggravated by lens wear. Understanding the precise cause allows for targeted changes that can restore comfortable wear.
Proper Lens Care and Replacement Schedules
The most frequent cause of contact lens discomfort relates directly to how the lenses are used and maintained. Overwearing lenses past the recommended daily hours is a major factor because it drastically reduces the amount of oxygen reaching the cornea. Since the cornea requires oxygen directly from the air, the lens acts as a barrier, leading to hypoxia, which causes corneal swelling and irritation. Sleeping in lenses, even those approved for extended wear, increases the risk of serious eye infections, such as microbial keratitis, due to the closed-eye environment fostering microbial growth.
Ignoring the prescribed replacement schedule allows for the accumulation of deposits on the lens surface. Tears contain proteins and lipids that naturally adhere to the lens material over time, and these deposits can trigger an inflammatory response in the eye. Failing to wash hands before handling lenses, or reusing old solution instead of using fresh solution daily, introduces bacteria and debris. This poor hygiene compromises the lens’s ability to remain clean and leads to chronic irritation and a gritty feeling.
Incompatibility with Lens Type or Fit
Sometimes, the problem is not user behavior but the physical characteristics of the lens or the solution used for cleaning. Contact lenses are precision medical devices defined by measurements like the base curve (BC) and diameter (DIA), which must precisely match the curvature and size of your eye. If the base curve is too “steep,” the lens grips the cornea too tightly, restricting the flow of tears and oxygen, leading to redness and discomfort. Conversely, a base curve that is too “flat” causes the lens to move excessively with each blink, resulting in irritation, unstable vision, and a higher risk of dislodging.
Sensitivity reactions to the lens care solution are also a common source of irritation. Many multipurpose solutions contain preservatives, such as polyhexamethylene biguanide (PHMB), that can absorb into the soft lens material and leach out, causing a toxic reaction on the cornea. Switching to a preservative-free hydrogen peroxide-based cleaning system often resolves this sensitivity, as these systems fully neutralize the disinfectant before the lens is reinserted. The oxygen transmissibility (Dk/t value) varies significantly between older hydrogel lenses and newer silicone hydrogel lenses, with the latter offering substantially higher oxygen flow, which directly impacts comfort for long-day wearers.
Medical Reasons for Intolerance
Underlying ocular health conditions can create an environment where contact lens wear is no longer tolerable. Dry Eye Syndrome (DES) is the primary biological reason for lens intolerance. The lens rests on the tear film, disrupting its stability and increasing tear evaporation. The lens material may absorb the limited tear film, increasing friction between the lens and the eye surface, resulting in a gritty, burning sensation and redness.
Another common reaction is Giant Papillary Conjunctivitis (GPC), which is an inflammatory response of the inner upper eyelid to chronic irritation or deposits on the lens. GPC causes the formation of small, dome-shaped bumps (papillae) on the underside of the eyelid, which then rub against the lens and cause discomfort. Seasonal and environmental allergies also exacerbate discomfort because the moist surface of the lens can attract and trap airborne allergens, holding them directly against the eye.
It is important to differentiate between chronic discomfort and acute danger signs, such as infectious keratitis. Symptoms like sudden, worsening pain, extreme light sensitivity, significant blurred vision, or a discharge require immediate attention. This condition can lead to severe vision loss and suggests an urgent medical situation.
Immediate Action and Professional Consultation
If you feel significant or worsening discomfort, immediately remove the contact lenses and switch to wearing glasses. Do not attempt to reinsert the lenses until the symptoms have completely subsided, as continued wear can worsen irritation or progress an infection. This temporary cessation allows the cornea and the ocular surface to recover from any stress, inflammation, or mechanical trauma caused by the lens.
If the discomfort, redness, or blurry vision persists for more than 24 hours after removal, or if you experience severe symptoms like intense pain or sensitivity to light, consult an eye care professional right away. When seeking a diagnosis, bring your current lens brand, the specific solution you use, and a detailed account of your wearing schedule. This information assists the doctor in determining if the issue is behavioral, material-related, or due to an underlying medical condition, allowing them to recommend a change in lens type, solution, or treatment plan.