Healthy Living

What Tests Determine Conjunctivitis?

What Tests Determine Conjunctivitis?

Key Takeaways

  • Viral conjunctivitis usually starts in one eye, but the infection can easily spread to the other eye.
  • Bacterial conjunctivitis is usually due to staphylococcus and streptococcus bacteria. 
  • If you suspect that you have conjunctivitis, you should visit an ophthalmologist to get tested and know exactly how to treat and manage the condition.

Conjunctivitis is a very unpleasant eye condition that may cause discomfort and pain in the eyes. This disease has to be medically treated. Thus, it’s important to determine the causes and triggers of this disease. If you suspect that you have conjunctivitis, you should visit an ophthalmologist to get tested and know exactly how to treat and manage the condition.

During your doctor’s appointment, you will be asked about your symptoms and medical history as well as undergo an eye examination. Most of the time, your doctor can identify whether your conjunctivitis is due to a viral or bacterial infection or if it is caused by an allergic reaction. If you have conjunctivitis, your eyes may appear red and swollen. However, there are also other symptoms depending on what causes your eye infection. Your symptoms are usually the basis of your doctor’s diagnosis. Sometimes, doctors will have a hard time coming up with an accurate diagnosis since the symptoms of most eye infections seem alike no matter the cause.

There are some particular tests that can determine the type of conjunctivitis you have, but first, the doctor will ask you if you have family members who have a history of chronic conjunctivitis. After that, you will have to answer a few simple questions to help your doctor diagnose your condition. You must also inform the doctor if you have shared the same blankets, pillows, towels, or makeup supplies to other people. If your conjunctivitis is caused by bacteria or a virus, then you can directly transmit the infection to others through your contaminated things. To determine whether the infection is bacterial or viral, the ophthalmologist will run some laboratory tests.

Slit Lamp Exam

By using a slit lamp, which is an instrument that has a binocular microscope and a high-energy light beam, your doctor can tell if you have conjunctivitis. In a slit-lamp examination, a bright source of light is shone into your eye. This beam of light will allow your doctor to closely examine your eyes, especially the cornea. Other parts of the eye can also be examined such as the conjunctiva, the iris, and the sclera (the white part of the eye). Moreover, you doctor may add a drop of fluorescein dye into your eye for a more detailed examination. By adding this dye, any damage to your eye’s surface can be clearly identified.

Next, the doctor will check for visual changes of the conjunctiva and other eye tissues. Samples of tears, secretions, and conjunctival tissues will then be collected for laboratory analysis. The procedure is called a "swab test", where a cotton swab is used to collect a sample of the mucus of the infected eye. This sample will also be sent to the laboratory for analysis. Based on the results, the doctor will be able to determine what kind of treatment you will have.

Viral Conjunctivitis

The most common causes of conjunctivitis are the ones that can cause colds. The same with other mucous membranes such those in your nose and ears, your eyes are also prone to infections.

Viral conjunctivitis usually starts in one eye, but the infection can easily spread to the other eye. You will remain contagious for a week up to 15 days. However, the infection tends to go away on its own within a few days or up to two weeks. The symptoms of viral conjunctivitis include eye redness, itching, and a clear watery discharge. Many people with conjunctivitis complain about a blurry vision and stuck eyelids upon waking up in the morning. While they are sleeping, eye discharges accumulate causing their eyelids to get glued together.

Bacterial Conjunctivitis

Bacterial conjunctivitis is usually due to staphylococcus and streptococcus bacteria. This type of conjunctivitis is common among adults and just like viral conjunctivitis, bacterial conjunctivitis is also highly contagious. Most cases of bacterial conjunctivitis can be easily treated. However, there are some bacterial strains that can cause a serious damage if they are not treated as soon as possible. One condition would be gonococcal conjunctivitis, which is caused by the same bacteria responsible for gonorrhea, a sexually transmitted disease. 

One condition would be gonococcal conjunctivitis, which is caused by the same bacteria responsible for gonorrhea, a sexually transmitted disease. This bacterial strain can damage the cornea by penetrating into its surface. Its symptoms include eye redness, itching, general eye discomfort, and a thick whitish-yellow discharge. Like viral conjunctivitis, you will most probably have a sticky mattering of the eyelids when you wake up in the morning. Moreover, bacterial conjunctivitis can cause vision impairment if not aggressively treated right away. 

Allergic Conjunctivitis

Allergic conjunctivitis happens when your eyes are exposed certain allergens that can cause an irritation. Unlike viral and bacterial conjunctivitis, allergic conjunctivitis is not contagious as the condition only occurs as a response to inflammation that is caused by allergens such as pollen, pet dander, and dust, among others. Your body responds to these particles by releasing a protein molecule called histamine. Histamine release causes redness, itching, and tearing of your eyes. 

Most allergens are seasonal, which only occur at particular times of the year or at specific environments or places. The most common allergens you may encounter are smoke from cigarettes, dust, and pet dander. The symptoms of allergic conjunctivitis are almost the same as the other types of conjunctivitis, but with intense itchiness and a characteristic string-like whitish discharge. 

There is no specific test that can tell the difference between viral or bacterial conjunctivitis. That is why a swab test is usually done. In cases like this, the laboratory may use the RPS Adeno Detector to establish a diagnosis of viral infection and exclude a bacterial infection. If the test is negative on viruses and the patient is still having conjunctivitis symptoms, there are two more possibilities: bacterial infection or allergic reaction. If there is an allergic reaction, the doctors will run allergy tests.

Based on the results, the doctor can diagnose a few types of conjunctivitis:

  • acute viral conjunctivitis
  • allergic conjunctivitis
  • chemical conjunctivitis
  • blepharitis
  • anterior uveitis, episcleritis, and scleritis

Nearly all cases of bacterial infections can be diagnosed using swab tests. You should take a specific list of medicines to cure the condition. After your conjunctivitis is cured, you have to continue living with proper hygiene and following the instructions given by your doctor.

For the treatment of bacterial conjunctivitis, your doctor can prescribe you antibiotic eye drops or ointments, which will help prevent the infection from coming back.

Viral conjunctivitis begins in one eye and then infects the other eye in a few days. There is no particular cure for viral infections. If the condition is caused by the herpes simplex virus, your doctor may prescribe you an antiviral medication.

There are many possible treatments for allergic conjunctivitis such as a combination of antihistamines and mast cell stabilizers or drugs that help control inflammation such as decongestants, steroids, and anti-inflammatory eye drops.