Prolonged or incorrect use of contact lenses may expose you to the risk of eye infections and inflammationssuch as microbial keratitis or dry eye syndrome.
The benefits and risks of LACs
Le contact lenses (LAC) are the solution increasingly adopted by those who need corrective eye lenses.
LACs are often preferred to spectacles because they are less bulky, more convenient to handle and above all because they are aesthetically invisible.
However, the prolonged and, above all, incorrect use of LACs can lead to a number of complications, such as dry eye syndrome or the microbial keratitis (CM), one of the latter's most severe and sight-impairing complications.
Dry eye
Dry eye syndrome or 'dry eye', referred to in medical parlance as 'dry keratoconjunctivitis', is a multifactorial disorder that affects the tear film and ocular surface. It is accompanied by an increase in the osmolarity of the tear film and inflammation of the ocular surface.
Symptoms
The most common symptoms of dry eye include forms of ocular discomfortsuch as burning, foreign body sensation, difficulty in opening the eyelids, especially upon waking; visual disorderssuch as blurred vision and photophobia, tear film instability with potential damage to the ocular surface.
Microbial keratitis
The term 'keratitis' groups a heterogeneous group of inflammatory processes affecting the cornea. Infectious forms are among the main causes of blindness and can be caused by bacteria, viruses, fungi or protozoa.
Symptoms
Symptoms vary greatly depending on the cause, but generally eye irritation, pain, blurred vision and photophobia (hypersensitivity to light) are always present.
Prevention
In order to avoid, or at least reduce, the risk of occurrence of disorders related to the use of LACs, one should, in fact, adopt good practices of ocular hygiene especially in order to prevent any microbial infections which can eventually lead to microbial keratitis.
Epidemiology
Microbial keratitis including the bacterial keratitis, fungal and from Acanthamoeba, affect the cornea, leading to inflammatory processes.
The causes behind their occurrence may be different, but the trauma mechanical is often the main cause.
Epidemiological studies have shown that the incidence of microbial keratitis varies according to both the pathogen responsible for the infection and the type of contact lens used: the use of night-time LACs, for example, compared to daily LACs, is correlated with a higher risk of CM occurrence.
Causes
Under normal physiological conditions, the corneal surface is protected from microbial infection by several protective mechanisms; among these is the tear fluid, which, thanks to the secretion of two molecules, lactoferrin and lysozyme, performs an important antimicrobial function.
In addition, thecorneal epithelium constitutes a real physical barrier, which is able to prevent the entry of microorganisms.
However, as a result of mechanical trauma or due to the incorrect use of contact lenses, the body's natural defences can be compromised and the eyes, in this case, become more susceptible to microbial infections.
Risk factors
The risk factors underlying the occurrence of microbial keratitis are multiple and often non-modifiable, such as male gender, genetic predisposition and socioeconomic status.
Others, on the other hand, depend on some bad habits or incorrect ocular hygiene practices, so they can be modified in order to reduce the likelihood of the disease itself.
Modifiable risk factors include, for example, the prolonged use of Night LACssmoking, cleansing of LACs with unsuitable solutions or failure to wash hands before use are among the most common.
Furthermore, clinical data have shown that the use of aesthetic contact lenses, such as those used to obtain an eye colour different from one's own, can be the cause of microbial keratitis.
Symptoms and signs
Symptoms
The symptomatological picture varies depending on the pathological agent responsible for the keratitis (bacterial, fungal or from Acanthamoeba).
In general, the symptoms associated with bacterial keratitis occur immediately and include photophobia (hypersensitivity to light), pain and eyelid swelling; if, on the other hand, one is dealing with a fungal keratitis, the symptoms occur 5-10 days after infection, as fungi take longer to grow than bacterial species.
Signs
The clinical signs in this case depend in turn on the fungal agent responsible for the infection.
Infections by Candida cause inflammation of the corneal epithelium with 'round' edges; if, on the other hand, it is Aspergillus, the edges of the corneal epithelium will be 'feathered'.
Finally, the clinical signs of keratitis by Acanthamoeba are ring-shaped infiltrates and perineuritis, which, however, may also be absent.
Treatment
Treatment depends on the type of keratitis and is determined by the medical specialist following a careful evaluation of the patient's clinical picture.
In general, therapeutic intervention strategies involve the administration of antibiotic, antifungal and anti-inflammatory drugs
Â
English 
Italian 
Spanish