Contact lenses offer a popular and convenient method for correcting various vision impairments. These thin, corrective devices sit directly on the eye’s surface. A common question is whether wearing contact lenses can lead to a deterioration of vision over time.
Contact Lenses and Vision Progression
Contact lenses do not cause vision to worsen. They are medical devices designed to correct refractive errors by focusing light onto the retina. This corrective action does not alter the eye’s physical structure or accelerate any underlying vision conditions. Studies, such as the Adolescent and Child Health Initiative to Encourage Vision Empowerment (ACHIEVE) study, found no significant difference in short-sightedness progression between children who wore contact lenses and those who wore glasses. Refractive errors, like myopia (nearsightedness), can progress naturally, especially during childhood and adolescence, regardless of contact lens use.
Factors Affecting Vision and Eye Health
While contact lenses do not inherently worsen vision, issues related to their use can create the perception of deteriorating eyesight or cause discomfort.
One common issue is dry eye syndrome, which contact lenses can exacerbate or induce. Lenses can absorb moisture from the eye, disrupting the tear film and leading to symptoms such as dryness, grittiness, or blurred vision. The tear film needs to remain balanced for consistent eye moisture, and contact lenses can interfere with this balance.
An improper lens fit or an incorrect prescription can also lead to blurry vision or eye strain. If a lens is too tight or too loose, it can cause fluctuating vision and force the eyes to work harder to focus. This constant adjustment can result in eye fatigue, headaches, and light sensitivity. Additionally, a poorly fitted lens can reduce oxygen flow to the cornea, leading to irritation and fatigue.
Over-wearing contact lenses or sleeping in them poses significant risks, primarily due to corneal hypoxia, a lack of oxygen to the cornea. The cornea receives most of its oxygen directly from the air. Lenses act as a barrier, and prolonged wear can restrict oxygen diffusion, leading to swelling (edema) and new blood vessel formation (neovascularization). These conditions can cause discomfort, redness, and temporary vision changes, and if left unaddressed, can lead to permanent vision impairment.
Poor hygiene practices significantly increase the risk of eye infections, such as microbial keratitis. Acanthamoeba keratitis, a severe and painful infection, is often linked to exposing contact lenses to tap water, which contains microorganisms. These infections can cause pain, redness, and in severe cases, permanent vision impairment or even blindness. Allergic reactions to lens materials or cleaning solutions can also cause irritation, redness, and discomfort, which might be mistaken for worsening vision.
Essential Contact Lens Care
Proper contact lens care routines are important for maintaining eye health and clear vision.
Wash hands thoroughly with soap and water before handling lenses. Using a lint-free towel for drying hands is also recommended.
Cleaning and storing lenses correctly involves using only recommended solutions. Tap water should be avoided for rinsing or storing lenses due to the risk of severe infections. Lenses should be rubbed gently with a few drops of solution and then rinsed thoroughly before being placed in a clean lens case filled with fresh solution. Never reuse or “top off” old solution, and replace the lens case every three months to prevent bacterial buildup.
Adhering to the prescribed wear and replacement schedule (e.g., daily, bi-weekly, monthly) is important for eye health. Over-wearing lenses beyond their recommended duration can lead to oxygen deprivation and other complications. Unless specifically prescribed extended wear lenses, sleeping in contact lenses should be avoided, as it significantly increases the risk of eye infections and corneal issues. Regular eye exams with an eye care professional are important to monitor eye health, assess lens fit, and update prescriptions as needed.
Understanding Natural Vision Changes
Vision can change due to natural processes or underlying eye conditions, separate from contact lens wear. Myopia (nearsightedness) often progresses during childhood and adolescence, a change that occurs independently of contact lens or glasses use. This progression can continue into early adulthood.
Age-related changes also affect vision. Presbyopia, an age-related farsightedness, develops around age 40, making it difficult to focus on close objects. Cataracts, involving the clouding of the eye’s natural lens, affect older adults and can cause blurred vision, glare, and faded colors.
Glaucoma, a group of eye diseases that damage the optic nerve, can lead to vision loss, starting with peripheral vision and sometimes progressing without noticeable symptoms in its early stages. These conditions are natural progressions or diseases that would occur regardless of contact lens use. New or persistent vision changes should prompt a consultation with an eye care professional, as they are indicative of an underlying condition requiring diagnosis and management.