Área Oftalmológica Avanzada Dr. Vergés . C/Dalmases 42, 08017 Barcelona     |     93 551 33 00     |     info@cverges.com
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Conjunctivitis is a term that means inflammation of the conjunctiva, without specifying the cause. Generally, conjunctivitis is the most common cause of "red eye".

The white of the eye (the sclera) is covered with a thin membrane called the conjunctiva, which has fine blood vessels and capillaries that are not to be seen with a naked eye. When the conjunctiva becomes irritated or swollen, the blood vessels become much more prominent and the eye take the characteristic reddish appearance.


There are many causes of eye irritation that can cause conjunctivitis. The most common are infections, allergies and environmental irritants. The conjunctiva is a uniform tissue, therefore it responds to these stimuli in a similar manner, leading to the common phenomenon of red eye.

Infectious causes of conjunctivitis include bacteria and viruses such as staphylococcus or streptococcus.  The red eye is associated with mucus secretion or, in severe cases, pus. Conjunctivitis can affect one eye or both.

If the secretion is profuse, it is likely that it is an acute infection. In these cases, it is advisable not to delay an examination by the ophthalmologist. In some circumstances, some bacterial infections are more chronic and many cause little or no secretion or small crusts on the eyelids in the morning.

Viruses are also common cause of conjunctivitis. Some viruses cause classic family contagious conjunctivitis and may be accompanied by sore throat and rhinitis. Unlike bacterial conjunctivitis, the secretion is more like liquid, a watery profuse tearing.

Infectious conjunctivitis, bacterial or viral, can be quite contagious; the contact with the tears of the patient through the use of tissues and towels should be unique to each person to eliminate the risk of infection. Washing hands after examining the patient also helps prevent the spread of the infection.

Allergies tend to cause a type of conjunctivitis that produces a more watery secretion, similar to the viral ones, but they are accompanied by other symptoms such as itching, rhinitis and seasonality-related reasons. Some types of allergies, such as hay fever, cause strong itching, while others simply produce a chronic redness.

Finally, environmental irritants such as cigarettes or smokes in general can cause conjunctivitis.

It is significant to know that a dry eye condition enhances conjunctivitis. Hence, in patients with the "dry eye" syndrome, this pattern will be taken into account to prevent more troublesome symptoms and unreasonable healing period.


There are several eye diseases that also trigger a red eye and can be very severe, leading to blindness unless adequately diagnosed and treated.

To avoid misdiagnosis or simple confusion of the sufferer, refer to an eye care specialist. This is especially important if there is pain, blurred vision and severe photophobia (sensitivity to light), these symptoms are not typical of a simple conjunctivitis and indicate a greater degree of severity.

The pain, blurred vision and severe photophobia may signal the presence of glaucoma, eye ulcer or inflammation inside the eye; diseases that can affect vision irreversibly, therefore under these circumstances we recommend to visit the ophthalmologist urgently.

If you want to make an appointment or have questions please complete the form with all details and we will contact you at the earliest opportunity.