Blink and You Might Miss It: How Contact Lenses Affect Your Vision

February 5, 2018


Part I in A Multi-Part Series


Approximately 30,000,000 Americans wear contact lenses, and there are many medical and societal issues surrounding their use.  Occupational Health and Safety Professionals must understand the risks and benefits associated with contact lens wear.  The next few articles will revolve around contact lenses.  We will discuss the benefits and potential risks of contact lens wear not only for eye health but also visual performance and safety in the workplace.  

Contact lenses are regulated by the FDA.  They rest upon the most complex and vulnerable exposed surface of your body.  They alter the physiology of the eye.  They alter human perception.  Improperly fit or worn contact lenses are a significant cause of preventable eye disease and have consequences for human visual performance.  The Centers for Disease Control and Prevention address contact lens use at some length:


While this article goes into some detail, I consider doctors and safety professionals to be partners in protecting employee health and wellness.  To that end, this article explains in some detail just one factor affecting how contact lenses impact the eye.  It's a factor we all take for granted: the blink.


The Blink


Your eyelid is the Zamboni machine of your eye.  And like the Zamboni, blinking is something we take for granted.  However, blinking is a vitally important physiological function: it exfoliates the eye; it functions in tear spreading, freshening, and drainage; it contributes to a neurological cycle involved in eye surface maintenance including skin growth and repair as well as immune protection.


Your contact lens gets in the way of all of this.  Prolonged use of the same contact lens alters the fit of the contact lens as prescribed by your doctor and will interfere with the important functions of blinking.  This leads to a spiraling cycle of declining visual stability and growing ocular health risk.  This is a complex topic, but we can think of the spiraling problems as unfolding as follows.  Impaired blinking leads to:

  1. Tear Stagnation: Inefficient flushing of old and deposition of new tears.  Dead skin, mucous, environmental debris, and make- up are some items that stagnate with impaired blink function and turn your tears into something approximating slime. This slime coats your lens and leads to:




  2. Coated Lens: When the contact lens becomes coated, it loses transparency with an obvious effect on vision.  This leads to blurred vision, loss of contrast vision, increased sensitivity to glare.  The coating also leads to:

  3. Increased Friction: The eyelid grabs the contact lens and lifts it out of place, leading to randomly blurred and distorted vision. The friction chafing on the eyelid causes:

  4. Giant Papillary Conjunctivitis:  The underside of your eyelid is smooth like the inside of your cheek.  Friction creates folded mounds of swollen overgrown skin with coalesced strings of dead skin, mucous, and grit between the folds. This leads to discomfort, itching, and severe contact lens intolerance.

  5. Impaired Immune Function:  This all creates a “red alert” state and elevated stress levels for your eye’s immune protections.  This leads to unhealthy inflammation and irreparable damage to the tear secreting glands of the eyeball and eyelids.  The eye's protective mechanisms against infection become less efficient exposing a person to:

  6. Microbial Keratitis: An infection of the cornea of the eye.  This extremely painful infection is treated with high doses of antibiotics and usually leads to permanent scarring with effects on vision.  The costs in medical care, human suffering, and lost productivity are high.  Severe corneal infections in people who do not wear contact lenses are not common.  Severe corneal infections in people who wear contact lenses are relatively common.

Contact Lens Wear and Care

Consult with your doctor.  My professional advice includes, in part, the following tips:

  1. Empty old solution every day.  Do not "top off" or add new solution on top of old.

  2. Do not use “store brand” or “Plain label” solutions.  I recommend exclusively hydrogen-peroxide based solutions such as Clear Care ™.  I have no financial interest in this product.

  3. Do not mix solution with water or store your lenses in water.

  4. Do not swim in contacts or use a hot tub in contacts.

  5. Do not sleep in contacts.  Discuss with your doctor.

  6. Do not wear contacts longer than your doctor prescribes.

  7. Do not mistake being relatively problem free during a period of improper contact lens wear to be evidence that poor contact lens habits are “ok for my eyes.”  

What’s Not Normal

There is never a time that a healthy human eye displays the following unless it is sick or injured in some way:

  1. Redness

  2. Feelings of dryness, grittiness, itching, burning

  3. Fluctuating vision with blink

  4. Red eyelid margins

  5. Debris in eyelashes

  6. Pain or achiness

As always, I welcome questions and comments.  The next article will address Multifocal/Bifocal and “Monovision” contact lens wear and potential implications for visual performance.  


Dr. Mark Kahrhoff

Complete Safety, LLC


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