Conjunctivitis (‘red eye’ or ‘pink eye’) is the commonest cause of red eye, and at some-time, your friends, family members or you yourself may have suffered from it. However, there are also many other causes of red eye.
What is conjunctivitis?
Conjunctivitis (‘itis’ means inflammation, here of the conjunctiva – a thin transparent covering of the white portion of the eye or the sclera) is one of the common causes of red-eye. Inflammation occurs due to an irritant source (like an infection, allergen, or other irritating substances), and the redness occurs as the blood vessels enlarge (dilate) to increase blood supply to tackle the source of irritation. Signs of inflammation are redness, swelling, and pain/irritation.
Is conjunctivitis always contagious? Know the types of Conjunctivitis
Conjunctivitis caused by an infection (bacteria, or virus), is contagious (spreads by contact but does not spread by looking at the infected person’s eye!). However, the non-infectious causes of conjunctivitis are not contagious.
Bacterial or viral conjunctivitis typically spreads from contaminated water and surfaces, so it is common in the rainy season. Infective conjunctivitis generally lasts for a week or two. It is sometimes a challenge to differentiate bacterial from viral conjunctivitis. Some clues include –
- Bacterial conjunctivitis can also be a result of ear and sinus infections, while viral conjunctivitis can start with or follow a common cold or sore throat (pharyngitis).
- Bacterial conjunctivitis can involve one or both eyes, while the viral one typically starts in one eye and then goes on to the other.
- The discharge is thick, sticky, and yellowish in bacterial infections (with lids crusting and sticking together especially in the mornings), while it is more clear, watery and teary, in the viral type.
Bacterial conjunctivitis is treated with antibiotic drops or ointment, whereas, viral conjunctivitis does not respond to antibiotics, but runs its course just like the common cold, and resolves spontaneously. Supportive care like cold compresses and eye drops to bring symptomatic relief from the dry gritty feeling, and irritation, are often prescribed in viral conjunctivitis.
Sometimes the diagnosis of whether the conjunctivitis is bacterial or viral is in doubt. Also in certain cases of viral conjunctivitis, there is a risk of also developing a secondary bacterial infection (like in cases of a common cold with sinus or ear infections, low immunity, contact lens wear, etc). So, antibiotic drops are usually prescribed in such cases.
Eyecare tips during bacterial/viral conjunctivitis for sufferers and caregivers:
These are not contagious. Allergy is the most common cause of non-infectious conjunctivitis. The clues which tell you it is allergic and not infective conjunctivitis are both eyes involvement simultaneously, and prominence of itching. Sticky discharge is usually absent. There may be other signs of allergy present (like accompanying sneezing, known history of hay fever/nasal allergies or asthma, seasonality with pollen, or repeated attacks with known/unknown triggers), and absence of other infections of ear, throat, and sinus. Allergic conjunctivitis is treated with antiallergic medicines orally or as eye drops (antihistamines, corticosteroids and cromoglycate).
Contact lens wearers may develop irritation or allergy to their lenses which causes conjunctivitis, requiring temporary discontinuation of lenses.
Conjunctivitis can also come on due to irritants like smoke, pollution, chemicals, sprays, cosmetics or something (foreign body) entering the eye. The conjunctivitis is transient and settles down with eye washing and avoiding or removing the irritant.
OTHER CAUSES OF RED EYE
Dry eyes can also cause the eyes to appear dull red, Dry eyes occur after prolonged computer use which decreases the blinking rate and tears circulation, and is also commonly seen in the elderly, in dry environments, due to direct AC blast, working in hot dry environments or with air pollution. Dry eyes can sometimes be difficult to differentiate from allergic conjunctivitis. There is a characteristic allergy history and prominence of itching in allergic conjunctivitis, while dry eyes feel more tired and have a ‘sandy’ sensation, with worsening of symptoms after prolonged screen work, reading or end of the day. Sometimes tear film tests may be carried out to confirm dry eyes. Lubricant eye drops can provide relief.
Sometimes there may be a deep-red prominent patch in one part or side of the eye with relatively much less or absent redness in the rest of the eye. This is due to bleeding from the rupture of one of the blood vessels. Conjunctival blood vessels are thin and fragile and can rupture after a fingernail or other injury, a bout of strenuous cough, or even straining while passing stool. However, often no reason can be found. This is called subconjunctival hemorrhage and usually resolves on its own. Though it looks prominent it does not cause any symptoms.
Lid infections, called blepharitis (often associated with dandruff) along the lash line, or stye (a focal swelling and collection of pus) can also make eyes appear mild or dull red (though far less than the redness seen in conjunctivitis).
Eyes can also appear red due to lack of sleep, too much smoking, intake of alcohol or certain medicines.
Apart from surface causes of red eye (as seen above related to the tears, lid and conjunctiva), red eyes could also represent a manifestation of diseases of other parts of the eye that may be more serious or concerning (like corneal abrasions/ulcer or keratitis, scleritis, uveitis, glaucoma, cellulitis or tension headaches/migraine).
The following alert signs are useful to suspect the same which require immediate consultation and referral to an eye specialist for detailed eye examination and investigation-
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