Your Lens and Eye Health

What We Should Know About Contact Lenses

The human eye is one of the wonderful gifts of the nature; it is the window to the world, and a mirror to the human body. A contact lens is a state-of-the-art temporary prosthesis that makes the vision quality when compatible with this precious organ and can be used for optic, aesthetic and therapeutic purposes. A contact lens is always in contact with specific and valuable tissues of the eye since it is placed on the surface of the eye. This close contact may sometimes produce many adverse reactions.  

A human body is equipped with protective systems against external effects. Contact lenses may be detected as a foreign body by these systems and trigger an allergic response when used incompliance with the recommendations of a doctor. In addition, use of an inappropriate lens in improper conditions may activate some resistance points, producing an infection risk to the eye.   

The basic rules, which are formed by medical knowledge and supported by the law, should be followed to establish a healthy and successful relationship with lifelong contact lenses.

What Are The Basic Rules To Determine The Most Suitable Contact Lenses For The Eye?

The first and most important one of these rules is to use contact lenses after an examination and under supervision of a doctor. An ophthalmologist is provided with long and extensive training to evaluate any features of a human eye. They must have wide knowledge about high eye pressure, loss of transparency of ocular lens (cataract), retinal diseases (retinal thinning or detachment, decollement, macular degenerations), or vital problems of the brain and body reflecting on the eye as well as optic problems of the eye. Thus, an individual, who visits an ophthalmologist for examination for contact lenses and their use, will benefit from this wide knowledge and have an opportunity for protecting his/her eye health as well as use of contact lenses. Also, an examination for contact lenses is a specific practice on its own and even an original art branch of medicine. Thus, contact lens examination and practice should be performed safely in a particular setting prepared for this procedure and by doctors who are the experts in this field.

  1. What are the major steps in an examination for contact lenses?
  2. A complete examination of the eye is performed by an ophthalmologist before use of contact lenses;
  3. Then the most suitable contact lens is selected for the eye,
  4. It is placed on the eye under supervision of the ophthalmologist,
  5. Its position and move on the eye is controlled,
  6. Information about placing, removing and cleaning is provided to prescribe.

How Should I Supply My Contact Lenses?

Each contact lens has different features as each patient has own characteristics.  
One of the basic features is the inner face obliquity of a contact lens, which should be compatible with the corneal obliquity of that person.  
 Another variable is the material of which a contact lens is made. Each material is different in oxygen permeability, water retention, and surface contamination. Ocular surface tissues need to breathe, in other words, have adequate oxygen in order to survive. The contact lenses with inadequate oxygen permeability or incompatible inner surface obliquity will cause ocular tissues to become damaged and protective system of the eye to break. In such environment, undesired germs may be localized and produce ulcers, putting the eye health in jeopardy.

Contact lenses should be supplied upon a prescription after a doctor’s examination.

Over-the-counter contact lenses pose a great risk because no examination has been performed, resulting in major defects in selection of proper lenses, practice, patient education, and control.  

I feel sorry to say that young population, even in adolescence period, can easily gain access to over-the-counter color contact lenses and carelessly use the contact lenses as if they were wearing some accessories such as earrings or hair clips without supervision of a doctor whatsoever; they even swim with their contact lenses on in a swimming pool or sea, or take a shower, and exchange their lens. As a matter of fact, color contact lenses pose as great risk as other lenses and even sometimes greater risk than those due to unconscious usage. One reason for this is that although color contact lenses must be replaced once a month, there is misdirection that they can be used for 6 months and even 1 year. The prescription of contact lenses prepared by support of Turkish Society of Ophthalmology (TOD) provides technical specifications and use details of any lenses including color lenses.  

These readily available prescriptions are medical and legal documents to help protect your eye health, and a source where we can find recommendations of doctors as in other prescriptions.  

It is highly important for a contact lens user to be well acquainted with the contact lenses, to have a full understanding of how to place and remove contact lenses, and to be fully informed about contact lens care systems. It is because the patients will be alone will their contact lenses after examination and initial placement, and an unaware fault might put their eye health in serious jeopardy. Thus, it is important to select correct lenses and use properly as well as to provide the user with correct information about how to properly use the contact lenses in their personal life.

To have adequate knowledge, a contact lens user should practice on how to place and remove the contact lenses, be informed of rules of use, and have careful training about cleaning procedures in an appropriate time. One should remember that contact lenses should not be purchased in haste adopting an approach “try these besides the glasses”; this will cause serious problems in life.

Wash your hands properly before touching your contact lenses and the lens containers with soapy water and let them dry out in open air every day. You should replace the containers each month to prevent the risk that wear-related cracks may produce a suitable environment for germ growth.

Contact lenses retain water, as a sponge, in various volumes of water depending on the different materials used by each manufacturing company. Water content in a lens has a significant effect on the oxygen permeability as well as softness of the material. But it is also paves the way for the germs that can be transmitted by hands or water to settle easily on the lens or even sometimes in the lens.

On the other hand, tap and pool water contains many highly resistant ameba type germs. Use of contact lenses outside recommendations of a doctor; swimming in a pool, or having a sauna or a shower with contact lenses on will pave the way for germs to settle in the eye and produce a treatment-resistant infection, which is the mostly feared situation by an ophthalmologist.

How Frequent Should Use of Contact Lenses Be Controlled?

Unlike glasses, contact lenses have a dynamic interaction with the eye. They might cause decreased amount of oxygen on the surface of the eye or insensitivity by altering transmission characteristic of optic nerve in time depending on mechanical effects. Thus, the users of contact lenses might not immediately realize the problems with their eye, resulting in delayed diagnosis and treatment. The users of contact lenses should therefore visit their doctor in a suitable time interval (app. in 6 months) to detect the changes even though they have no complaints. So, an ophthalmologist will have an opportunity to detect any changes with potential risk overlooked by the user and see the usage errors of the user and timely warn them about misuse.

How Frequent Should I Replace My Contact Lenses and How Long Should I Keep Them On The Eye?

One of the most common faults is not to replace contact lenses in recommended time and to keep them on the eye longer than required on the same day. Contact lenses are always in touch with tear and ocular tissues as well as with factors such as dust, heat and air exchange in the outer environment. Therefore, the surface of the lens will be covered with some materials of tear (e.g. protein and mucin) and the accumulated dust in the environment where the user lives; the ratio of the water is altered; this will result in change in oxygen permeability of the lens and adverse effect on visual performance of the lens. In fact, all these could be overcome replacement of contact lenses each month but the same lenses are used longer than the recommended time to reduce the cost, which leads to infections and allergic reactions and puts the eye health in jeopardy.

The currently adopted usage behavior is daily use/monthly replacement. However, getting into habit of single-use contact lenses will remove the need for cleaning solutions; prevent the abovementioned accumulation to form, and gain time.    

Can I Sleep With My Lenses On?

Another major mistake to sleep with the contact lenses on even though the eye doctor has recommended the otherwise, or against doctor recommendations. The cornea can easily supply the required oxygen from the air when the eyes are open during the day. The pressure of oxygen lowers when the eyes are closed in sleep and in normal circumstances ocular tissues are able to maintain their vital functions at this adequate level of oxygen for decreased but decelerated metabolism in sleep. However, contact lenses constitute a mechanical barrier between the cornea and atmospheric oxygen and may interfere with provision of adequate amount of oxygen for ocular superficial tissues depending on the gas permeability of material they are made of. This problem will get bigger especially when the eyes are closed.

This problem has largely been overcome by lenses with a higher oxygen permeability produced in line with the recent technological developments, and special lenses have been produced, which you can leave on while you are sleeping. However, the recent scientific research has indicated that the oxygen permeability is not enough alone but the mechanical trauma produced by contact lenses also play an important role in the eye health. In addition one should remember that each eye has a specific tolerance limit to stresses like anoxia and therefore an eye doctor decides on contact lenses by considering this personal difference.

As seen, use of contact lenses is a chain of rules managed by an ophthalmologist and of which each is based on scientific rules. For a proper use of contact lenses, both the ophthalmologist and scientific facts are essential.

On the other hand, the laws authorize and assign the ophthalmologists to protect the eye health. It must not be performed by any other professions (1).

The contact lenses purchased outside such rules have major defects in selection of proper lenses, practice, patient education, and control since they are not prescribed by an ophthalmologist, and there are legal and conscientious responsibility for those who act outside these rules.


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The information on this website is not intended to replace any medical advice given by physicians with access to your detailed medical history.