Contact lens discomfort, often described as dryness, is a common experience that turns clear vision into a gritty, irritating ordeal. This sensation signals a breakdown in the balance required to keep the lens and the eye’s surface hydrated. Dryness typically manifests as a sandy or foreign body sensation, fluctuating vision, or an inability to wear lenses comfortably for a full day. Understanding the factors contributing to this problem is the first step toward finding lasting relief.
Issues Related to Contact Lens Material and Care
The physical properties of the lens itself play a direct role in how dry your eyes feel throughout the day. Modern soft contacts are made from two primary materials: hydrogel and silicone hydrogel. Hydrogel lenses rely on a high water content to transmit oxygen to the cornea, but this water can evaporate in dry conditions, causing the lens material to shrink and feel tight on the eye.
Silicone hydrogel lenses, an advanced alternative, allow significantly more oxygen to pass through the material directly, even with lower water content. While beneficial for eye health, the silicone component can be hydrophobic, or water-repelling, which may lead to reduced surface wettability for some users. This lower wettability can cause the lens to feel dry or sticky, especially toward the end of the wearing schedule.
Over time, your tears leave behind deposits of proteins, lipids, and mucins that naturally adhere to the lens surface. This buildup reduces the lens’s ability to remain smooth and hydrated, leading to a hazy appearance and a gritty feeling. Replacing lenses strictly according to their prescribed schedule, whether daily or monthly, is necessary because the accumulation of these deposits interferes with the lens-eye interface.
The solutions used to clean and store lenses can also inadvertently contribute to discomfort. Many multipurpose solutions contain preservatives, such as Benzalkonium Chloride (BAK), which are designed to keep the solution sterile. These chemicals can be absorbed by the lens material and then slowly released onto the eye, causing irritation or a low-grade allergic reaction that manifests as chronic dryness. For individuals with sensitive eyes, hydrogen peroxide-based cleaning systems offer a preservative-free alternative, though they require a neutralizing step to prevent a painful chemical burn upon insertion.
How Environmental Factors and Habits Exacerbate Dryness
External conditions and daily routines often accelerate the evaporation of the tear film, making the eyes and contact lenses feel parched. Low-humidity environments created by forced-air heating or air conditioning actively pull moisture from the ocular surface, leading to faster tear evaporation.
Direct exposure to airflow, such as from car vents, ceiling fans, or outdoor wind, creates a localized increase in tear evaporation. This prevents the tear film from stabilizing and forces the tear glands to work harder to maintain lubrication. This environmental stress quickly leads to the uncomfortable sensation of a dry contact lens sticking to the eye.
Prolonged use of digital screens is a major cause of contact lens dryness because it profoundly affects blinking dynamics. When concentrating on a computer, phone, or tablet, the average person’s blink rate can drop from a normal range of 15 to 20 blinks per minute to as low as five to seven. These blinks are also often incomplete, failing to spread the oily layer of the tear film fully across the lens surface.
This reduced blinking allows the tear film to break up much faster than usual, leaving the contact lens exposed and dry. Furthermore, particulate matter (PM2.5) from air pollution and chemical irritants from tobacco smoke directly contact the eye, triggering inflammation. These airborne irritants disrupt the tear film’s lipid layer, further destabilizing the eye’s moisture balance.
Underlying Biological and Tear Film Conditions
Contact lens dryness can stem from an underlying issue with the body’s ability to produce or maintain a healthy tear film. The tear film is a complex three-layered structure composed of a mucus layer, a watery layer, and an outermost oily layer.
Meibomian Gland Dysfunction (MGD)
A common medical cause of evaporative dry eye is Meibomian Gland Dysfunction (MGD), where the tiny oil glands in the eyelids become blocked or produce poor-quality meibum. This oil is necessary to seal the tears and prevent them from evaporating too quickly, so a deficiency in the lipid layer results in rapid tear loss. Even if the eye produces enough water, the tears will be unstable and the contact lens will quickly dry out. MGD is a chronic condition that requires diagnosis and treatment from an eye care professional.
Numerous systemic medications can also reduce overall moisture production throughout the body, including in the eyes. Anticholinergic drugs, such as first-generation antihistamines, certain decongestants, and some tricyclic antidepressants, are known to decrease tear secretion by blocking specific receptors in the tear glands. Other medications, including diuretics and beta-blockers used for blood pressure, can reduce the aqueous (watery) component of tears by affecting the body’s fluid balance.
In addition to medications, aging decreases the capacity of the lacrimal glands to produce tears. Hormonal fluctuations, such as those experienced during menopause, can also alter the composition and stability of the tear film. These factors often require a medical assessment to distinguish them from simple environmental or lens-related dryness.