Bacterial conjunctivitis is a prevalent condition globally. In the US, it affects 135 out of every 10,000 people each year, making up about 1% of all primary care appointments.

Pink eye, also known as conjunctivitis, is a common condition that causes the eye to appear pink and red. It can also cause discharge and discomfort. In this blog, we will go over the basics of pink eye, including the different types, symptoms, and treatment options.

What you need to know about different types of pink eye

There are three main types of pink eye: viral, bacterial, and allergic.

• Viral pink eye - This is the most common type and is often referred to as "classic pink eye." It typically presents with red, watery eyes and minimal mucus discharge. It can be irritating or itchy, but is usually not painful. This type of pink eye is highly contagious, so it's important to keep your hands clean and avoid sharing towels, linens, or anything that comes into contact with the eye. It is recommended to schedule an eye exam and stay home for at least three to seven days after symptoms appear.
• Bacterial pink eye - This type of pink eye is similar to viral pink eye in that it can cause red eyes and can easily spread from one eye to the other. However, it is characterized by more mucus discharge and can be more painful. It is important to see an eye doctor for treatment with antibiotics to control the infection. Like viral pink eye, it is recommended to stay home until symptoms have minimized or for 24 to 48 hours after starting antibiotics.
• Allergic pink eye - This type of pink eye is caused by an allergic reaction or irritation. It can cause red, watery eyes, swelling, and itching. Both eyes are usually affected at the same time. It is not contagious, so there is no need to limit close contact with others. Treatment options include over-the-counter allergy eyedrops or prescribed steroid drops to reduce inflammation.

Other causes of red eyes or pink eye

One of the important reasons to see your eye doctor for pink eye or red eye is because there are so many potential causes, and it is important to identify the cause of the symptoms in order to provide the best treatment and prevent any potential vision complications.

While some of the following may be uncommon, a longer list was included to show why symptoms of red eye may not always be what you think and should be evaluated by your optometrist.

Some examples of why our eyes may be red include:

• Conjunctivitis (pink eye) - an infection of the conjunctiva, the clear membrane that lines the eyelid and covers the white part of the eye. It can be caused by viruses, bacteria, or allergens and is characterized by red, swollen, and itchy eyes.
• Allergies - an overreaction of the immune system to certain allergens such as pollen, mold, or pet dander. It can cause red, itchy, and watery eyes.
• Dry eyes - a condition in which the eyes do not produce enough tears or the tears evaporate too quickly. It can cause redness, burning, and stinging sensations.
• Blepharitis - an inflammation of the eyelids, which can be caused by bacterial or sebaceous gland dysfunction. It is characterized by red, swollen, and itchy eyelids, and can also cause crusting or flaking of the eyelashes.
• Uveitis - an inflammation of the uvea, which is the middle layer of the eye. It can cause redness, pain, light sensitivity, and vision changes.
• Glaucoma - a group of eye disorders that can cause increased pressure in the eye and damage to the optic nerve. It can cause redness, eye pain, and vision changes.
• Trauma - an injury to the eye that can cause redness, swelling, and pain. This can include blunt trauma such as a black eye, or a penetrating injury from a foreign object.
• Subconjunctival hemorrhage - a small blood vessel in the eye that breaks and causes a red or pink spot on the white of the eye. It is usually benign and requires no treatment, but can be caused by trauma, high blood pressure, or other underlying health conditions.
• Corneal abrasion - a scratch or scrape on the clear front surface of the eye (cornea). It can cause redness, pain, and sensitivity to light.
• Foreign body in the eye - an object that gets trapped in the eye, causing redness, pain, and discomfort.
• Herpes simplex virus - a viral infection that can cause redness, pain, and blisters on the eyelid and the eye.
• Herpes zoster virus - a viral infection that can cause redness, pain, and blisters on the eyelid and the eye.
• Adenovirus - a viral infection that can cause redness, pain, and blisters on the eyelid and the eye.
• Chlamydia trachomatis - a bacterial infection that can cause redness, pain, and discharge in the eye.
• Mycoplasma pneumoniae - a bacterial infection that can cause redness, pain, and discharge in the eye.
• Staphylococcus aureus - a bacterial infection that can cause redness, pain, and discharge in the eye.
• Streptococcus pneumoniae - a bacterial infection that can cause redness, pain, and discharge in the eye
• Neisseria gonorrhoeae - a bacterial infection that can cause redness, pain, and discharge in the eye.
• Haemophilus influenzae - a bacterial infection that can cause redness, pain, and discharge in the eye.
• Moraxella catarrhalis - a bacterial infection that can cause redness, pain, and discharge in the eye.
• Acute angle-closure glaucoma - a medical emergency in which the pressure inside the eye suddenly increases, leading to severe eye pain, redness, and vision changes. It requires immediate medical attention. It's important to keep in mind that red eyes or pink eye can have multiple causes, and it's crucial to visit your optometrist for a proper diagnosis and treatment.

It is important to note that some of the causes of red eyes can be serious and require medical attention, while others are minor and can be treated at home. It is important to visit your optometrist if you are experiencing red eyes, especially if it is frequent, or is accompanied by pain, vision changes or discharge.