อาการ สาเหตุ โรคตาแดง Pink eye (Conjunctivitis)

Pink eye (Conjunctivitis)

Pink eye (Conjunctivitis) is an infection of the conjunctiva which is a transparent membrane covering the surface of eyeball and inner layer of eyelid. When conjunctival blood vessels are inflamed,

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Pink eye (Conjunctivitis)

Conjunctivitis is an infection of the conjunctiva which is a transparent membrane covering the surface of eyeball and inner layer of eyelid. When conjunctival blood vessels are inflamed, they become more visible, causing your eye to appear pink or reddish.

The common causes of conjunctivitis include infection by virus or bacteria, an allergy and incompletely opened tear duct in newborns.

Conjunctivitis irritates your eyes, but your vision is rarely affected. The discomfort can be relieved with treatments. Conjunctivitis is contagious, so a prompt diagnosis and treatment are essential to help prevent the transmission to others.

Symptoms

  • Red and irritated eye(s)
  • Gritty, crusty covering and sticky eye(s) due to discharge
  • Increased tearing


When to see a doctor

Redness in the eye can be the result of severe eye problems including eye pain, foreign body sensation, blurry vision and light sensitivity. You should seek immediate medical attention if you experience these symptoms.

Once you have conjunctivitis, you should stop wearing contact lenses. If your symptoms do not improve within 12-24 hours, see your ophthalmologist to ascertain the cause and other potential eye problems associated with the use of contact lens.

Causes

Pink eye may be a result of:

  • Viral infection
  • Bacterial infection
  • Allergies
  • A chemical splash in the eye
  • A foreign object in the eye
  • A blocked tear duct in newborns.

Viral and bacterial conjunctivitis

The most common cause of conjunctivitis is adenovirus. Other possible causes are herpes simplex virus, varicella-zoster virus, and other viruses, including the virus that causes coronavirus disease 2019 (COVID-19).

When you have colds or a respiratory infection including a sore throat, you may also get conjunctivitis caused by virus or bacteria. Not cleaning your contact lenses properly or wearing other people’s contact lenses can lead to bacterial conjunctivitis. 

Both viral and bacterial conjunctivitis are easily transmissible through the liquids that drains from the infected eye. One or both eyes can be involved.

Allergic conjunctivitis

The symptoms resulted from the reaction to allergens such as pollen which can affect both of your eyes.  Immunoglobulin E (IgE), a class of antibody, is produced in response to allergens. Mast cells in the mucous lining of your eyes and airways will be triggered to release histamines which are inflammatory substances.

When histamine is released, signs and symptoms of allergy including red or pink eyes will ensued. 

Symptoms of allergic conjunctivitis include sneezing, watery nasal discharge, intense itching, tearing and inflammation of the eyes. Most of the symptoms can be relieved with allergy eyedrops.

Conjunctivitis from irritation

Conjunctivitis may develop when a chemical splash irritates your eyes, or a foreign object gets into your eye. While trying to clean or get rid of the chemical or foreign object, your eyes can be irritated and become red. Symptoms such as watery eyes and mucous discharge may go away within one day.

Seek immediate medical care if your symptoms do not improve after rinsing with water or you get a caustic chemical splash such as lye. Your vision can be permanently damaged by a chemical splash. If your symptoms persist, a foreign body may still be lodged in the eyes, and it may scratch your cornea and sclera.

Risk factors

  • You are exposed to something to which you are allergic, causing allergic conjunctivitis.
  • You are exposed to patients with conjunctivitis caused by virus or bacteria.
  • You wear contact lenses, particularly extended-wear lenses.


Complications

Conjunctivitis is responsible for inflammatory cornea affecting vision in adults and children. To decrease the risk of complications, immediate diagnosis and treatment for eye pain, foreign body sensation, blurry vision and light sensitivity should be performed.

Prevention

To prevent the spreading of conjunctivitis, you should follow a good hygiene practice.

  • Avoid touching your eyes
  • Clean your hands regularly
  • Use only a clean towel or washcloth
  • Do not share your towel or washcloth
  • Do not share your personal eye care products
  • Discard your current eye makeup
  • Replace your pillowcases often

Conjunctivitis is as contagious as common cold. As long as you practice good hygiene, it is possible to return to work or school if you are not allowed to take days off.

Preventing pink eye in newborns

Newborn’s eyes are exposed to bacteria when moving through the mother’s birth canal. Mothers are not affected by those bacteria. However, they can cause a rare case of ophthalmia neonatorum or a development of a serious conjunctivitis which needs immediate treatment to preserve eyesight. Antibiotic ointment which prevents eye infection is usually applied to newborns’ eyes.

Diagnosis

A hospital visit may not be required in all cases. Your doctor can make a diagnosis after questioning about your symptoms and reviewing your medical history.

In rare cases, a sample of liquid from your eye may be needed for laboratory analysis. This happens in severe or high-risk cases involving sexually transmitted infection, or severe infection by bacteria or a foreign body in an eye.

Treatment

The treatment of conjunctivitis is mainly to soothe symptoms. The treatment includes the use of eyedrops, eyelid cleaning by a damp cloth and eye relief by a cold or warm compress.

The use of contact lenses must be stopped until the infected eye is fully recovered. Your doctor may recommend you discarding your disposable contact lenses.

Disinfect your conventional contact lenses before wearing them again. Consult your doctor if you need to replace your lens case used before and during conjunctivitis. Throw away eye cosmetics used before you have symptoms.

Antibiotic eyedrops are not necessary in most cases. Pink eye is usually the result of viral infection. Antibiotics can be harmful because they may cause a drug allergy or decrease efficacy in future use.

Viral infection usually needs up to 2-3 weeks to run its course. The symptom usually starts in one eye and within the next few days the other eye will be infected as well. Symptoms typically resolve eventually.

In case of viral conjunctivitis caused by the herpes simplex virus, antiviral medications may be prescribed.

Treatment for allergic conjunctivitis

If you have allergic conjunctivitis, you may need a specific eyedrop for people with allergies which contain antihistamines and mast cell stabilizer to control the allergic reactions. An eyedrop may contain decongestants, steroids, and anti-inflammatory drug as well.

Eyedrops with antihistamines and anti-inflammatory drugs at a pharmacy can also help relieve your symptoms. Consult your doctor for more information about which eyedrop you should use.

Avoiding the causative agent of your allergies can also soothe your allergic conjunctivitis symptoms.

Home remedies and lifestyle modification

To soothe your symptoms, at home you can try the following:

  • Cold or warm compress
    You can make your own compress by soaking a clean and lint-free washcloth into cold or warm water, wringing out the water and applying it on your affected eye. The cool touch of the compress is usually soothing to your eye, but some may prefer a warm compress. Do not apply the same cloth on the unaffected eye to prevent cross contamination.
  • Eyedrops
    You can soothe your symptoms by using eyedrops. Some eyedrops or artificial tears with antihistamines or other medications can soothe the symptoms of allergic pink eye.
  • Contact lenses
    Stop using contact lenses while your eyes are affected. How long you cannot wear contact lenses depends on the cause of your symptoms.

      Consult your doctor whether you should buy a new single-use contact lenses, cleaning solution and case. For conventional contact lenses, please rinse and disinfect them before reuse.

      Preparing for your appointment

      If you have any eye-related symptoms that worry you, seek medical care. You may need to see an ophthalmologist if your condition gets worse.

      What you can do
      Prior to your doctor’s appointment, check if there are any restrictions you must follow. You may need to stop using eyedrops or contact lenses and take note of the followings:

      • Your symptoms related or unrelated to pink eye
      • Medications and dietary supplementary you have been taking
      • Questions you would like to ask

      Sample of questions you may want to ask your doctor:

      • What causes pink eye?
      • Do I have to undergo any tests?
      • What are the treatment options?
      • After the start of treatment, am I still contagious?
      • Are there any other alternative medicines you can recommend?
      • Where can I find more information about pink eye?
      • Is a follow-up visit necessary?

      What to expect from your doctor
      Sample of questions that you may be asked:

      • When is the symptom onset?
      • Have you experienced the symptoms occasionally or continuously?
      • Are your symptoms serious?
      • What relieves your symptoms?
      • What aggravates your symptoms?
      • Is one or both eyes affected?
      • Do you usually wear contact lenses?
      • How do you care and clean your contact lenses?
      • Do you change a storage case of contact lens often?
      • Have you been with anyone with cold, flu or conjunctivitis?

      What you can do in the meantime
      Stop wearing contact lenses until your symptom is fully resolved. Clean your hands often to reduce the chance of transmission. Do not share your personal belongings such as a handkerchief or towel with other people.




      Article by

      Dr Thitima Wungcharoen
      Ophthalmologist Specialist in Cornea, External Disease, & Refractive Surgery

      Doctor Profile

      Article by

      • Dr Thitima Wungcharoen
        Dr Thitima Wungcharoen A Ophthalmologist Specialist in Cornea, External Disease, and Refractive Surgery

      Published: 16 Mar 2022

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