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Contact lenses are a fantastic alternative to glasses. In fact, they allow an estimated 125 million people around the world to enjoy a full field of vision, better comfort, and more flexibility. Plus, they can be worn for the correction of nearsightedness, farsightedness, astigmatism, presbyopia, and several corneal diseases.
To get the most out of your contact lens experience, it is important to practice healthy wearing habits. Contact lenses are medical devices and must be prescribed by an eye care provider to ensure they fit the eye correctly, even if worn for aesthetics.
In this article, I’ll define what contact lens overwear is as well as review 5 serious complications that can occur from overwearing contact lenses.
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Where a contact lens sits on the eye
Before we dive into what contact lens overwear is, it’s important to understand some basic anatomy of the eye.
The cornea is the clear, dome-shaped structure at the front of the eye serving as a protective barrier and responsible for focusing light rays. The cornea is transparent and does not contain blood vessels, receiving oxygen from the atmosphere and nutrients from the tear film outside the eye and aqueous humor at the inside of the eye.
In order for your vision to be clear and comfortable, your cornea must be free of surface irregularities and maintain its transparent nature. The conjunctiva is the clear thin membrane that lines the inner surface of the eyelids and covers the sclera, the white part of the eye.
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What is contact lens overwear?
Examples of not practicing healthy contact lens wearing habits include sleeping in contact lenses when not FDA approved, extending contact lenses beyond their recommended replacement schedule, and not disinfecting them properly.
Below I’ll review both noninfectious and infectious complications of overwearing contact lenses. These complications carry a risk of vision loss ranging from minimal to potentially vision-threatening.
1) Contact lens acute red eye (CLARE)
CLARE is an inflammatory reaction of the cornea and conjunctiva which is associated with overwearing and sleeping in contact lenses. It is more common in people who wear soft contact lenses versus rigid gas permeable but can occur with any type of lens.
CLARE causes the eye to become red, painful, watery, and light-sensitive. This occurs because of a reduction in the amount of oxygen reaching the cornea and the subsequent immune response.
The severity of CLARE depends on a few factors including how long the contact lenses have been overworn, the thickness and movement of the contacts, and how oxygen-permeable the contact lens material is. Every brand of contact lenses has an oxygen permeability value which tells eye care providers how much oxygen passes through the contact lens and reaches the cornea.
How is CLARE treated?
Treatment is straightforward and involves temporarily discontinuing contact lens wear. Occasionally, topical steroids are prescribed to aid in the healing process.
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2) Corneal neovascularization
Another consequence of overwearing contact lenses includes developing neovascularization, or new blood vessels, on the surface of the eye. As discussed earlier, the cornea does not contain blood vessels so that it remains transparent. An inadequate supply of oxygen to the cornea is the driving force for these new blood vessels to develop. These small blood vessels start growing around the edges of the cornea and can spread centrally.
Patients who develop neovascularization may not have symptoms such as redness or eye pain. Blurred vision may result from scarring of the new blood vessels and resultant corneal shape changes.
How is corneal neovascularization treated?
Treatment includes reducing contact lens wear time, switching to a healthier silicone hydrogel lens, changing to a frequent replacement or daily disposable lenses, or even stopping lens wear altogether.
3) Corneal abrasion
Corneal abrasions, or scratches to the cornea, are one of the most common eye injuries in the United States. Eye injuries account for about 3% of all visits to the emergency room with corneal abrasions accounting for 14% of them.
Your cornea can be scratched by just about anything that comes into contact with your eye including dirt, wood shavings, and metal particles. Symptoms of corneal abrasion include redness, light sensitivity, pain, and tearing.
Corneal abrasions are more common with rigid gas permeable contact lenses due to their smaller diameter and sharper edges compared to soft or scleral contact lenses. If you wear a pair of contacts for longer than is recommended, a nick may develop in the edge of the lens and scratch your eye while wearing it. A corneal abrasion may also occur when inserting or removing contacts.
If you sleep in contact lenses it’s particularly more common for the lenses to dry out and stick to your cornea when you try to remove them. The dried out contact lens can rip off the surface layer of cells and result in abrasion.
How is a corneal abrasion treated?
Corneal abrasions often heal within 24 to 48 hours of occurring. Antibiotics are often prescribed to prevent infection when an abrasion has been caused by contact lens wear.
4) Giant papillary conjunctivitis
Giant papillary conjunctivitis, or GPC, occurs when the inside of your eyelids develop bumps and become red and swollen. Normally, the inside of your eyelids are nice and smooth.
How can contact lenses cause GPC?
People who wear soft contact lenses have the greatest chance of developing GPC, especially if they overwear or sleep in them. GPC results from chronic irritation as the edge of the contact lens rubs against the inner surface of the eyelid. The exact cause is not 100% known but it may be attributed to an allergy to the lens material or deposits on the surface of the lens.
Rarely, people who do not wear contact lenses may also develop GPC, for instance, if they have a prosthetic eye or stitches on the ocular surface.
GPC may cause your eyelids to swell and result in redness and itching. Itching and discomfort are often worse when you remove your contact lenses. You may also feel like your contact lenses are moving too much when you blink and develop blurred vision due to excess mucus production.
How is GPC treated?
Treatment includes limiting contact lens wear, switching to a daily disposable, avoiding multipurpose solution with preservatives, and topical steroids.
5) Corneal ulcer
One of the most serious consequences of overwearing contact lenses is developing a corneal ulcer. A corneal ulcer, also known as bacterial keratitis, is an infection of the cornea which can lead to permanent vision loss. While there are several other causes of corneal ulcers, contact lens abuse is one of the most common.
Falling asleep in your contacts one time is not likely to cause permanent damage, but people who sleep in contacts for extended periods of time are most at risk of developing a corneal ulcer, even if their particular contacts are approved by the FDA for doing so. According to the Centers for Disease Control and Prevention (CDC) sleeping in contact lenses makes you six to eight times more likely of developing a corneal ulcer.
Symptoms of a corneal ulcer include redness, severe eye pain, increased light sensitivity, blurred vision, discharge, and feeling like you have something in your eye. Other contact lens-related causes of ulcers include showering or swimming with your contacts and using tap water to store them versus appropriate disinfecting solutions.
How is a corneal ulcer treated?
Treatment includes discontinuing contact lens wear and aggressive antibiotic treatment. In some cases, a corneal culture is needed to further aid in treatment.
While contact lenses are a great way to give yourself a break from wearing glasses and experience clear and comfortable vision, it is important to follow the advice of your eye care provider regarding replacement and disinfecting your contact lenses.
Not doing so may cause you to suffer unnecessary eye pain, pay for an expensive visit to your eye care provider, and even lose permanent vision.
What are your thoughts on the potential complications of contact lens abuse? Let me know in the comments below.