What is it?
Contact lenses are curved lenses that are placed on the surface of the eye with the purpose of correcting visual defects. These lenses are graduated according to the patient’s needs and are usually transparent, although in some cases they contain a slight touch of color to facilitate their placement.
The use of contact lenses is becoming more and more frequent in our environment. According to the Spanish Vision White Paper, it is estimated that around 7.4% of the Spanish population between the ages of 12 and 65 wears contact lenses. This number represents about 2.5 million people.
It is important to know the different types of lenses and the injuries they can cause if not used properly.
Types of lenses
There are different types of lenses depending on the case of each patient and visual defect to be corrected:
Soft contact lenses: They are used to compensate mild refractive errors in patients with myopia, hyperopia and astigmatism. This type of lens is usually made of hydrogel and new advances, such as silicone lenses, allow more oxygen to reach the eye, preventing eye irritation.
Rigid contact lenses: they are smaller, harder and less flexible than soft ones. They are used in patients with high astigmatism or in cases with corneal irregularities.
Scleral or semi-scleral contact lenses: they are advisable for patients with severe dry eye as they are larger and stiffer and can be filled with artificial tear, which allows the eye to be permanently moist
Orto-k: They are lenses that are placed during the night and are indicated for patients with myopia, hyperopia or astigmatism. This type of lenses have a shaping effect on the cornea during the night, while we sleep, so that when the patient removes them in the morning they can see well throughout the day without having to wear glasses or contact lenses.
Depending on the recommended time of use, we can also classify them as daily, biweekly, monthly or long-term.
Placement of lenses
To correctly wear contact lenses and avoid possible damage or infection, the following steps should be followed:
- Wash and dry your hands thoroughly.
- Take the contact lens out of its case and check which eye it belongs to.
How do you know which eye each contact lens corresponds to?
In case you have the same prescription in both eyes, the placement in the left or right eye is irrelevant. If you have a different prescription in each eye, the optician will provide you with two boxes, one labeled as left eye (LE) and the other as right eye (RE).
3. Place the lens on the forefinger of your hand to check that the lens is clean and not upside down.
How do I know if the contact lenses are in the right or upside down position?
Once placed on the forefinger, the shape of the lens will indicate whether it is upside down or right-side up. The ophthalmologist will be able to help you identify it correctly at the time of the first fitting.
4. Hold the upper eyelid with the middle finger of the other hand and the lower eyelid with the middle finger of the hand holding the contact lens.
5. Place the contact lens on the eye while looking upwards.
6. Once the contact lens is in place, remove your finger and gradually release the lower eyelid and then the upper eyelid.
With contact lenses in, you can enjoy corrected vision without glasses.
It is important to correctly follow the instructions of our ophthalmologist or optician, in addition to the instructions provided by the manufacturer of the lenses. Incorrect use of contact lenses can cause visual conditions with serious consequences for our vision.
How to remove lenses
To remove the contact lens correctly, follow these steps:
- Wash and dry your hands thoroughly.
- Stand in front of a lighted mirror and look up.
- Use the forefinger of your other hand to hold the upper eyelid of your eye.
- With the middle finger of the dominant hand, hold the lower eyelid.
- Gently pinch the lens with the tips of the thumb and forefinger to dislodge it and pull it out of the eye. If you pinch too hard, the lens may break.
- Place the lens in the other hand.
What injuries can contact lenses cause?
Contact lenses can lead to irritations, allergies, injury by rubbing and infections. This will depend on the type of lens, the hygiene and the cure that we have of the products that are used to clean and the manipulation of the lenses made when we used them.
It is rare that allergies are produced by the material of the lens (it is rare). The most common is due to the accumulation of the deposits that are formed and the preservatives dissolved in the cleaning products.
Corneal abrasions (scratches or rubbing) give rise to intense pain with tearing, ocular redness, discomfort to light, foreign body sensation and intolerance to the lens (shape, measurement, etc.) or alterations of the lens by notches or breaks.
The symptoms of blurred vision, halos of colours and intolerance to the lens (reddish, foreign body sensation, tearing, etc.) can appear if the lenses are worn too long.
Infections are usually rare, but they can be very dangerous and cause loss of vision in the eye.
Lens hygiene and preservation
Contact lenses require good care, since an expired contact lens or one with insufficient or incorrect hygiene can cause scratches on the cornea (corneal abrasions), allergy (depending on the manufacturing material) or infections.
For this reason it is important to follow the steps below:
- Clean your hands with soap and water before putting in or removing contact lenses.
- Put in your contact lenses before makeup and remove them once you have removed your makeup. It is important to put in contact lenses 20 minutes after getting up and take them out 20 minutes before going to bed. With the exception of Ortho-k lenses, do not sleep with contact lenses in.
- Do not wear lenses when showering or bathing.
- Use a new solution each time you clean your lenses, since reusing the solution may no longer be sterile. Contact lenses should not be cleaned with water, saliva or a homemade saline solution. Always use a disinfecting solution purchased from a pharmacy. Follow the manufacturer’s instructions exactly.
- Clean the lens case with sterile solution and not with water. The case should be replaced from time to time. Check with the manufacturer.
- Rest from time to time. Do not wear the lenses for long periods of time and do not wear damaged or broken lenses. If you feel itching, dryness, discomfort or blurred vision, remove your lenses.
- Do not rub your eyes vigorously when wearing contact lenses, as this may cause irritation or injury to the cornea.
- If you are traveling with contact lenses, bring a spare pair of contact lenses along with your glasses, so that you can combine them or in case you need a replacement.
- In environments with strong air conditioning, such as airplanes, contact lenses can dry out and cause discomfort. For this reason, it is advisable to wear glasses or carry moisturizing drops so that they can be administered if necessary.
Contact lenses also require some care, especially when they are used for going to the beach or swimming pool. In such cases, there are several things to keep in mind:
- If you are in the water, wear swimming goggles.
- Always wash your hands before handling or cleaning contact lenses, especially if you have been in contact with chlorine, sand or sunscreen.
- After bathing, wait for a while and then remove the lenses to clean them properly with a specific solution to remove any germs.
- When wearing contact lenses, protect your eyes with sunglasses whenever you are outdoors.
Symptoms of contact lens misuse
Contact lenses can lead to irritations and allergies, rubbing injuries and infections. This will depend on the type of lens, the hygiene and care we take (breakage, deposits, etc.), the products used for cleaning and the handling of the lenses when inserting them.
Allergies can be caused by the lens material (this is rare), but most commonly by the accumulation of deposits that form and by the preservatives dissolved in the cleaning products.
Corneal abrasions (scratches or grazes) result in severe pain with tearing, ocular redness, light discomfort, foreign body sensation and intolerance to the lens (shape, size, etc.), as well as alterations of the lens due to nicks or tears.
Symptoms of blurred vision, color halos and lens intolerance (red eye, foreign body sensation, tearing, etc) may appear if the lenses are worn for an excessive amount of time.
Infections are usually rare, but can be very dangerous and cause loss of vision in the eye.
In addition, external agents such as heat or the chemical substances contained in swimming pool water and sea salt in summer often cause irritative, viral or bacterial conjunctivitis, which can manifest with symptoms such as eye redness, stinging, burning, foreign body sensation, hypersensitivity to light or tearing.
Frequently Asked Questions
Who can wear contact lenses?
In general, any healthy person with refractive problems can wear contact lenses. However, there are cases in which lenses are not recommended, such as patients with severe allergies, people who work in dusty environments, patients with dry eyes or people who are not able to take proper care of the lenses.
What factors can cause an infection?
There are multiple factors that can favor the appearance of an eye infection due to contact lens use. Some of them are prolonged use of the lenses, lack of tears, lack of hygiene or external factors that may alter the condition of the eye and the lens.
What is the connection between lenses and keratitis?
Keratitis (inflammation of the cornea) can be caused by different elements, such as bacteria, fungi and, above all, microbes like acanthamoeba, which is very common among contact lens wearers and causes an infection that is difficult to treat. In the most serious cases it can cause scarring of the cornea and lead to vision problems that require a corneal transplant. It is very important to maintain good lens hygiene to avoid this type of infection.
Can I use eye drops if I wear contact lenses?
Not all eye drops are suitable for contact lenses, as unsuitable drops can cause serious corneal infections. It is important that if you need moisturizing eye drops, they are prescribed by your ophthalmologist.
Are cosmetic or colored contact lenses secure?
Cosmetic contact lenses should not be purchased from non-specialized sources. Colored cosmetic contact lenses or contact lenses for costumes should never be purchased in non-specialized centers. The supervision and prescription of an ophthalmologist is necessary for any type of contact lenses, since they will be in contact with the eye and their safety must be guaranteed.
How often do contact lenses need to be renewed and when do they expire?
There are different types of contact lenses and each has a specific lifetime, which can be daily, biweekly, monthly or long-term. To determine the renewal of your lenses, you should consult your optician to determine which type you have.
Can I wear contact lenses if I have conjunctivitis? And if I have a stye?
Contact lenses are not recommended if you have conjunctivitis or stye. It is important to remove contact lenses immediately if symptoms of conjunctivitis appear, since the use of lenses can worsen the infection. It is also important to wait to put contact lenses back in until the condition is completely cured.
From what age is it appropriate to wear contact lenses?
There is no minimum age for wearing contact lenses, since their use depends on the anatomical characteristics and refractive problems of each patient.
Contact lenses and coronavirus, is it advisable to use them?
There is no scientific evidence of a link between contact lens wear and coronavirus. However, experts recommend extreme hygiene measures such as hand washing to avoid transmission of the virus.