Contact lenses provide millions with clear vision, but when lenses dry out, it causes significant discomfort, irritation, and a gritty sensation. This dryness results from a complex interplay of the body’s natural tear function, the surrounding environment, and the physical properties of the lenses themselves. Understanding these root causes is the first step toward finding a solution for more comfortable lens wear.
How Tear Film Disruption Causes Dryness
The eye relies on the tear film, a thin coating composed of lipid (oil), aqueous (water), and mucin (mucus) layers, which maintain a smooth, hydrated surface. Placing a contact lens on the eye physically divides this structure into pre-lens and post-lens tear films, promoting instability and increasing evaporation. This disruption means the lens competes with the eye for moisture, often absorbing fluid from the underlying tear film.
Screen use significantly exacerbates dryness by affecting the natural blink reflex. When focused on digital screens, people blink substantially less often, sometimes dropping from 18 blinks per minute to as low as 3 to 7 blinks per minute. Blinking refreshes the tear film and expresses the oily layer from the meibomian glands. A reduced blink rate leads to a deficiency in the tear film’s lipid layer, causing the aqueous component to evaporate much faster.
Chronic wear can alter the function of the meibomian glands, which produce the lipid layer. Extended contact lens use affects the structure of these glands, potentially leading to blockages and reduced oil secretion. This accelerates tear film thinning and evaporation, contributing to dryness and discomfort. If the tear film becomes unstable, the lens can stick to the cornea, causing friction and irritation.
Environmental Factors Making Lenses Dry
External conditions actively pull moisture away from the lens and the eye’s surface. Low humidity environments increase the rate of tear film evaporation. This includes dry climates, high altitudes, and artificially controlled indoor spaces with air conditioning or central heating.
Air movement, such as from fans, car vents, or wind, accelerates tear evaporation. Quick air movement strips moisture from the lens surface, causing the material to dehydrate. Dehydration makes the lens stiffer and less comfortable, potentially reducing the amount of oxygen reaching the cornea.
Exposure to irritants like smoke, dust, and general air pollution contributes to dryness and discomfort. These particles deposit on the lens surface or irritate the eye, triggering an inflammatory response that further destabilizes the tear film. Symptoms of dryness and discomfort worsen significantly in low humidity conditions.
When Lens Material and Care Products Are the Culprit
The physical properties of the contact lens material determine comfort. Soft lenses are primarily made from two polymers: hydrogel and silicone hydrogel. Traditional hydrogel lenses rely on water content to transmit oxygen. Lenses with a higher water percentage are prone to dehydrating in dry conditions because they quickly absorb and release moisture, making the lens less comfortable and reducing oxygen flow.
Silicone hydrogel lenses use silicone to allow a higher volume of oxygen to reach the eye, independent of the lens’s water content. While these lenses offer superior oxygen permeability, the silicone component can sometimes make the lens surface less naturally wettable and more prone to collecting deposits from tears. Furthermore, wearing a lens beyond its recommended replacement schedule accumulates proteins and lipids from the tear film, significantly increasing surface irritation and dryness.
Incompatibility between the lens material and the cleaning solution is a common cause of dryness. Soft contact lenses, especially silicone hydrogels, can absorb components from multipurpose solutions, particularly preservatives. When the preserved lens is placed on the eye, these chemical agents are slowly released onto the ocular surface, causing irritation or inflammation. This preservative interaction can manifest as a burning sensation or corneal staining, contributing to discomfort.
Immediate Steps to Find Relief
Immediate relief comes from using rewetting drops specifically formulated for contact lenses. These drops are compatible with lens materials and provide a quick boost of moisture to the lens and eye surface. For sensitive eyes, preservative-free formulas are recommended, as standard preserved drops can sometimes interact with the lens material and increase irritation.
Adjusting screen habits mitigates dryness caused by a reduced blink rate. Following the “20-20-20 rule” instructs you to look away from the screen every 20 minutes at an object 20 feet away for at least 20 seconds. This practice encourages the eye to relax and reminds the wearer to perform full blinks, which refresh the tear film’s oily layer.
Simple environmental and lifestyle changes can make a difference. Using a humidifier in dry indoor spaces, such as an air-conditioned office or heated home, helps maintain a higher ambient moisture level, reducing tear evaporation. Adequate water intake supports overall hydration, which is necessary for maintaining a healthy tear film. If dryness is chronic, painful, or does not improve, an eye care professional can check for underlying conditions or recommend a different lens material or care system.