Conjunctivitis

There are parts of our body that have, among their functions, that of defending the body and, for this reason, they are among the first to be exposed to any risks.

The conjunctiva, the thin mucous membrane that covers the front of the eyeball and the inner surface of the eyelids, has the main task of protecting the eyes, defending the innermost parts from injury, trauma or from the entry of foreign bodies or harmful microorganisms. For this and because of its position, in the outermost part of the eye, the conjunctival membrane is easily exposed to the risk of inflammation. Let’s deal in detail with the different forms of conjunctivitis, the factors that trigger them, how to recognize them and how to treat them to avoid more serious consequences.

What is it

As anticipated, conjunctivitis is inflammation of the conjunctiva, the transparent mucous membrane that protects the eyeball (the white part of the eye) and covers the inner part of the eyelids. The inflammatory process can manifest itself in acute or chronic form.

Many possible causes

Conjunctivitis can be provoked by:

• viruses, bacteria or other microorganisms (and then we speak of infectious conjunctivitis)
• allergies (allergic conjunctivitis)
• general irritations (irritative conjunctivitis) due to physical or chemical factors (wind, soot, bright light, sunlamps, chemical agents, etc.).

Bacterial conjunctivitis is contagious and is generally transmitted through contact between secretions from eyes, hands and contaminated everyday objects (towels, pillows, etc.).

However, it should be noted that some bacterial conjunctivitis can also develop at birth, due to transmission of the bacterium responsible by the infected mother at the time of the passage of the newborn into the birth canal. It happens, for example, in gonococcal conjunctivitis.

There are many types of bacteria that can trigger conjunctivitis. The main culprits are streptococci and staphylococci.

To cause a particular and relatively frequent bacterial conjunctivitis, called angular because it is localized mostly in the corners of the eyes, is instead the bacillus of Morax-Axenfeld.

Less frequent, but more dangerous, is the aforementioned gonococcal conjunctivitis, caused by gonococcus, the same bacterium responsible for gonorrhea, a typically sexually transmitted disease. It can affect newborns from infected mothers and, if left untreated, can lead to blindness: for this reason, by law every child at birth is subjected to conjunctival prophylaxis to prevent any gonococcal infections.

Viral conjunctivitis is caused by viruses that are also highly contagious. It is often associated with a viral infection of the upper respiratory tract, such as a cold or sore throat. Incubation can last up to ten days. Numerous agents can trigger it: among the most frequent are adenovirus and viruses of the herpes family, in particular simplex and zoster.

Among the microorganisms that can trigger conjunctivitis, parasites, fungi and protozoa must also be mentioned.

Microorganism	Type of conjunctivitis
Pests	The plates, of the lice family, if infest the eyelashes with their excrements can trigger an irritation of the conjunctiva and consequent inflammation
Fungi	Very rare fungal conjunctivitis, but also difficult to recognize and long to treat
Protozoa	Amoebas, for example, can cause a rare but very serious keratoconjunctivitis, that is, an inflammation that, in addition to to involve the conjunctiva, it also affects the cornea causing then, in combination, a keratitis that may affect carriers of soft contact lenses.

In allergic conjunctivitis, eye irritation is linked to contact with substances that cause allergy (allergens), for example:

• pollen of some plants (grasses, cypress, hazel, birch, ragweed)
• Dust mites
• animal hair
• Perfumes
• cosmetics
• Molds
• medications.

Finally, among the irritative conjunctivitis, it is worth mentioning in particular actinic conjunctivitis, a consequence of excessive exposure to sunlight or tanning lamps (direct or glare) without the protection of sunglasses.

Conjunctivitis: the most common symptoms

Conjunctivitis is characteristically manifested by:

• red eyes (redness is due to dilation of the blood vessels of the conjunctiva, in fact we also speak of conjunctival hyperemia)
• itch
• abundant tearing
• secretion of pus.

Other symptoms are burning and swelling of the eyelids, blurred vision. Disorders may appear suddenly, sometimes associated with a feeling of discomfort with light (photophobia) and a foreign body sensation in the eye.

These symptoms are common to basically all inflammations of the conjunctiva, but there are also manifestations that may be more typical of one form rather than another.

The characteristic sign of bacterial type conjunctivitis is the sticky eye upon waking up with secretion of greenish-yellow pus. The type of secretion can however be variable, from the compound prevalent by mucus, to the muco-purulent up to the frankly purulent one, depending on the type of bacterium responsible and the severity of the infection. In some cases the secretions can coagulate to form a more or less adherent membrane on the inner surface of the eyelids and eye.

In viral conjunctivitis, the secretion is clearer, almost watery, and sensitivity to light may be more pronounced. In adenovirus conjunctivitis, parainfluenza symptoms are often associated (pharyngitis, swollen lymph nodes, cough, some lines of fever, etc.). In the case of herpes conjunctivitis, itchy and painful blisters may appear on the eyelid.

Both the most common infectious forms (bacterial and viral) can affect only one eye at a time, and then spread to the other.

Allergic-type conjunctivitis affects both eyes and is distinguished by the presence of intense itching sometimes even in the bottom of the throat, associated with sneezing, reddened eyes, profuse tearing and watery nasal discharge. Frequently, eyelid swelling is particularly evident. It occurs most often coinciding with the spring-summer flowering season, if the triggering allergen is seasonal (such as pollen), or can occur all year round in case of reaction to perennial allergens (such as mites).

In actinic conjunctivitis, the strong exposure to the sun, perhaps even worsened by the wind, tends to “dry” the conjunctiva causing a dryness that hinders the sliding of the eyelids on the eye itself and particularly favors redness, burning and the sensation of sand in the eyes.

Complications

Viral and bacterial conjunctivitis are contagious. In some cases, the microorganism responsible for the infection is resistant to treatment, causing relapses and partial or temporary loss of vision.

A neglected conjunctivitis (even allergic or irritative forms, but especially infectious forms) can extend to the eyelid (blepharitis), but above all to the cornea (keratitis), with the risk of giving rise to corneal lesions that can compromise vision.

For the useful diagnosis the eye examination

For an adequate and correct treatment of conjunctivitis it is better to contact the ophthalmologist for diagnosis, already at the appearance of the first symptoms.

In most cases, the specialist is sufficient to have a medical history (i.e. an interview with the patient to verify any opportunities for contagion and inquire about the symptoms) and the inspection of the eye with a special microscope, called a slit lamp, to establish at least as an indication, the type of conjunctivitis.

In the case of infectious forms, the ophthalmologist can take the secretions to undergo an examination and precisely identify the type of agent responsible for the infection. If it is a bacterial conjunctivitis, it may also be useful to use an antibiogram, an examination that allows to identify the type of antibiotic to which the bacterium is most sensitive.

Treatment

In case of bacterial and viral conjunctivitis, the eyes should be cleaned with sterile gauze or with the appropriate moistened eye wipes.

To avoid spreading the infection or resuming the infection it is essential to wash your hands well after touching the eyes and avoid sharing pillowcases, towels or cosmetics (mascara, eyeshadow).

Bacterial conjunctivitis is treated with eye drops or ointments based on antibiotics, applied topically, according to the doctor’s prescription. The nozzle of the eye drops should be kept at a distance from the infected eye to avoid contamination.

There are no specific treatments available for viral conjunctivitis, which resolves on its own within a week. Often, however, it can take longer to heal. The ophthalmologist can then prescribe anti-inflammatory (non-steroidal) eye drops to counteract burning and, sometimes, antibiotic eye drops to avoid bacterial over-infection. If conjunctivitis is due to herpes, you may prescribe a cure with an antiviral medication to be taken by mouth, to alleviate symptoms and promote healing.

The most effective prevention for allergic conjunctivitis is to avoid contact with allergens. Cold water compresses can also be useful to deflate the eyes and soothe itching. The use of antihistamine eye drops and antiallergic drugs, under strict medical supervision, helps relieve symptoms. The doctor, in particular, may prescribe ophthalmic ointments and / or eye drops containing cortisone, with an effective anti-inflammatory action, to be used however for a limited period due to the risk of side effects.

In the case of an irritative conjunctivitis (actinic in particular) the doctor usually prescribes the application of eye drops based on artificial tears to rehydrate the mucosa.

Regardless of the type of conjunctivitis, from the onset of symptoms to complete healing, contact lens wearers should not wear them, so as not to worsen eye health.

When to consult your doctor

It is advisable to consult the doctor whenever eye inflammation occurs, especially if it happens to children.

Self-prescription of drugs or the reuse of eye drops that may not be suitable for the treatment of new manifestations (not necessarily similar to the previous ones) or may have deteriorated or infected in the meantime are absolutely not recommended.

Only the doctor can diagnose the type of conjunctivitis, exclude the presence of foreign bodies in the eye and prescribe the appropriate treatment.