Section: Information In-depth
Causes of Red Eye
The severity of red discoloration and which portion of the eye affected will vary with the cause. Hyphema is caused by trauma or infection within the eye. Environmental irritants or infectious agents may cause conjunctivitis or eyelid swelling. Conjunctivitis with eyelid swelling and bulging of the eye is usually secondary to sinus disease or tumors.
Possible causes of red eyes include:
Bacterial infections. Bacteria can infect any portion of the eye and is a common cause of sinusitis. Common types of bacteria causing eye disease include: E. coli, pseudomonas, pasteurella, staphylococcus, streptococcus and mycoplasma.
Chlamydiosis. This is also known as Psittacosis or parrot fever.
Fungal infections. Aspergillosis, a fungus normally found in the environment, can cause severe sinus and ocular infections. A build up of exudate from Aspergillosis can cause bulging of the eye. Less common fungal infections include cryptococcus and candida.
Viral infections. These include poxvirus, paramyxovirus and herpesvirus.
Hypovitaminosis A. This is a low vitamin A concentration in the diet.
Irritation due to aerosolized dust and debris, smoke or aerosol sprays.
Neoplasia. Cancer can occur in the conjunctiva, nictitating membrane, within the globe itself or behind the eye.
Foreign bodies. Objects lodged under the nictitating membrane can cause red eyes.
Trauma. Bite wounds from mammalian pets or other birds and flying into objects, such as windows or mirrors are common causes of ocular trauma.
Allergies. Hypersensitivity reactions to dusts, molds or pollens may cause reddening of the conjunctiva.
