Health Risks
Contact lenses are generally quite safe when used correctly. Any complications related to their use are quite rare and affect about 5% of users every year.
Often, intolerance to the use of these medical devices is the consequence of the interaction between structural factors of the lens and the physiology of the anterior part of the eye; this results in changes in the cornea in terms of structure, tearing and oxygen levels. Many complications arise when contact lenses are worn differently than prescribed.These disturbances may also depend on the type of lens (for example: soft, rigid or gas-permeable), the frequency with which they are replaced, the cleaning systems adopted or other factors that depend on the wearer (example: incorrect application or failure to remove overnight).
The phenomena of intolerance and any complications can determine the onset of typical disorders of the contact lens wearer or amplify pre-existing eye diseases. The long series of problems that can occur ranges from minor discomfort to loss of vision, the result of a severe infection or "corneal ulceration."
According to some medical statistics, about 80% of contact lens wearers are unaware of the risks associated with wearing devices and their improper cleaning. It is a good idea to wear contact lenses for a limited time, always follow the instructions provided by the ophthalmologist for proper maintenance and schedule routine checks.
Predisposing factors
A small percentage of patients are not eligible to use these devices due to individual hypersensitivity or complex optical requirements. Knowing the causes of impaired contact lens wear is important to prevent more serious complications.
The improper use of contact lenses can adversely affect the eyelid, the conjunctiva and the various layers of the cornea. The most important risks are associated with the reduced supply of oxygen, necessary to meet the needs of the corneal surface; normally, the cornea obtains it. from tears and the surrounding environment during wakefulness, and from blood vessels at the back of the eyelid during rest. Contact lenses represent an oxygen barrier and wearing them for an extended period of time can produce effects such as blurred vision, eye pain and redness. This is why much research has focused on improving the materials they are made of. composed.
How contact lenses interact with the natural tear layer is also an important factor in determining device comfort and visual clarity. People with dry eyes are particularly vulnerable to discomfort and brief episodes of blurry vision. Dry eye can also be aggravated by concomitant factors, such as smoke, dust, air conditioning, and medications (for example: antihistamines, diuretics and psychotropic agents). For some patients, the correct choice of contact lens can minimize these effects. .
Factors contributing to developing a complication related to contact lens wear include:
- Patient suitability (local or general);
- Dry eye and reduced tear exchange under the lens (narrow lens syndrome)
- Infections (example: blepharitis, conjunctivitis, etc.);
- Allergic complications;
- Poor hygiene, such as improper maintenance and reuse (or refilling) of contact lens solution;
- Excessive use;
- Sleeping with lenses not approved for prolonged use;
- Environmental damaging factors;
- Systemic diseases;
- Trauma or surgery.
Contact lens wearers who present with pain, blurry vision, irritation or excessive tearing should raise a high degree of suspicion about the presence of possible lens-related complications, which is why their use should be discontinued pending investigations.
Proper handling, storage and cleaning of contact lenses are key steps to reduce the risk of an infection.