Author: Dr Val Phua
Estimated reading time: 9–10 minutes
Contact Lenses Are Safe—When Used Correctly
Contact lenses are an excellent alternative to spectacles and provide clear, convenient vision for millions of people worldwide. When fitted properly and cared for correctly, they are generally very safe.
However, contact lenses are still medical devices that sit directly on the surface of your eye. Poor hygiene, overnight wear or incorrect lens care can increase the risk of serious eye infections that may permanently affect vision.
Fortunately, most contact lens complications are preventable by following good lens hygiene and attending regular eye examinations.
How Do Contact Lenses Affect the Eye?
Unlike spectacles, contact lenses rest directly on the cornea—the clear front surface of the eye.
The cornea receives oxygen directly from the air. Contact lenses partially reduce this oxygen supply, particularly if worn for prolonged periods or while sleeping.
In addition, bacteria, fungi and microscopic organisms can adhere to contact lenses if they are not cleaned or replaced appropriately.
Good lens hygiene helps maintain:
- Healthy oxygen supply
- A stable tear film
- Clear vision
- Comfortable lens wear
- A healthy corneal surface
Common Contact Lens Problems
Dry Eyes
Dry eye symptoms are among the most common complaints in contact lens wearers.
Symptoms include:
- Burning
- Grittiness
- Blurred vision
- Lens discomfort
- Redness
Many patients experience significant improvement after changing lens materials, reducing wearing time or treating underlying dry eye disease.
Allergic Conjunctivitis
Proteins and debris may accumulate on contact lenses over time, leading to allergic inflammation.
Symptoms include:
- Itching
- Redness
- Mucous discharge
- Reduced lens comfort
Changing to daily disposable lenses may reduce these symptoms.
Corneal Abrasions
Small scratches on the cornea may occur if a damaged contact lens is worn or if lenses are inserted or removed incorrectly.
Most abrasions heal quickly with appropriate treatment, but prompt assessment is recommended.
Contact Lens-Related Infections (Microbial Keratitis)
Although uncommon, microbial keratitis is the most serious complication associated with contact lens wear.
Bacteria, fungi or parasites can infect the cornea and may lead to permanent scarring or vision loss if treatment is delayed.
Early diagnosis is critical.
What Increases the Risk of Eye Infections?
Several behaviours significantly increase the risk of infection.
These include:
- Sleeping in contact lenses
- Swimming while wearing contact lenses
- Showering with contact lenses
- Poor hand hygiene
- Using tap water to clean lenses or lens cases
- Wearing lenses beyond the recommended replacement schedule
- Topping up old disinfecting solution instead of replacing it
- Smoking
- Purchasing contact lenses without professional fitting
Sleeping in contact lenses is consistently recognised as one of the greatest risk factors for serious corneal infections.
Warning Signs That Require Urgent Review
Remove your contact lenses immediately and seek urgent ophthalmic assessment if you develop:
- Eye pain
- Redness
- Blurred vision
- Light sensitivity
- Excessive tearing
- White spot on the cornea
- Reduced vision
- Persistent discomfort
Do not continue wearing your contact lenses until you have been examined.
Daily Contact Lens Safety Tips
To reduce the risk of complications:
- Wash and dry your hands before handling lenses.
- Never sleep in contact lenses unless specifically prescribed.
- Never swim or shower while wearing contact lenses.
- Replace lenses according to the manufacturer’s schedule.
- Replace your lens case every three months.
- Use fresh disinfecting solution each time.
- Never use tap water or saliva to clean lenses.
- Remove lenses if your eyes become red or painful.
- Attend regular eye examinations.
Are Daily Disposable Lenses Safer?
Daily disposable lenses generally have the lowest risk of complications because a fresh sterile lens is used each day.
They also reduce:
- Protein deposits
- Bacterial contamination
- Lens cleaning errors
However, good hand hygiene remains essential.
Can I Sleep in Contact Lenses?
For most people, the answer is no.
Even contact lenses approved for extended wear increase the risk of corneal infection compared with removing lenses before sleep.
If you accidentally fall asleep wearing your lenses:
- Do not force them out immediately.
- Use lubricating eye drops if necessary.
- Remove them gently once comfortable.
- Avoid wearing them again until your eyes feel normal.
If redness, pain or blurred vision develops, seek prompt assessment.
How Often Should Contact Lens Wearers Have an Eye Examination?
Even if your vision is stable, regular contact lens reviews are important.
Most contact lens wearers should undergo an examination at least once a year.
More frequent reviews may be recommended for people with:
- Dry eye disease
- High prescriptions
- Previous infections
- Extended-wear lenses
- Underlying eye disease
Regular reviews allow early detection of complications before they affect vision.
Frequently Asked Questions
Can I swim with contact lenses?
Yes, but you must understand the inherent risks of doing so.
Water—including swimming pools, hot tubs, lakes and seawater—contains microorganisms that can adhere to contact lenses and increase the risk of serious infection, including Acanthamoeba keratitis.
Can I shower with contact lenses?
It is best to remove your lenses beforehand to reduce the risk of water-borne infection.
Is it safe to buy contact lenses online?
Only if you have been properly fitted and continue attending regular eye examinations.
Purchasing lenses without professional assessment increases the risk of wearing an inappropriate lens or missing early complications.
Are coloured cosmetic contact lenses safe?
Yes, provided they are prescribed, fitted and cared for in the same way as corrective contact lenses.
They should never be shared or purchased from unregulated sources.
The Bottom Line
Contact lenses are a safe and effective form of vision correction when worn responsibly. Most serious complications can be prevented through good hygiene, avoiding overnight wear, keeping lenses away from water and attending regular eye examinations.
If you develop redness, pain or blurred vision while wearing contact lenses, remove them immediately and seek prompt medical attention. Early treatment can make the difference between a quick recovery and permanent vision loss.
References
- American Academy of Ophthalmology. Contact Lens Care and Safety.
- Centers for Disease Control and Prevention. Contact Lens Health Week Resources.
- American Optometric Association. Contact Lens Care and Hygiene.
- British Contact Lens Association. Safe Contact Lens Wear.
- World Council of Optometry. Contact Lens Practice Guidelines.
