Pink eye is a type of eye infection, not a separate condition. The term “pink eye” refers specifically to conjunctivitis, which is inflammation of the thin, clear membrane covering the white of your eye and the inside of your eyelids. An “eye infection” is a broader category that includes pink eye but also covers infections in other parts of the eye, like the cornea, eyelids, or deeper internal structures. The distinction matters because pink eye is usually mild and self-limiting, while infections in other parts of the eye can threaten your vision.
Pink Eye Is One Type of Eye Infection
Conjunctivitis is the most common cause of eye redness seen in both primary care offices and emergency departments. It can be caused by viruses, bacteria, fungi, or parasites, but it can also be triggered by allergens or chemical irritants, meaning not every case of pink eye is actually an infection. Viral conjunctivitis is the most common infectious form, followed by bacterial conjunctivitis. Among non-infectious causes, allergies are the leading trigger.
Other eye infections affect different structures entirely. Keratitis is an infection of the cornea, the clear dome at the front of your eye. Blepharitis targets the eyelid margins. Uveitis involves deeper tissue, including the colored part of your eye (the iris) and the blood vessel layer lining the back of the eye. Each of these carries different risks and requires different treatment.
How Pink Eye Feels Compared to Deeper Infections
Pink eye is uncomfortable but rarely painful in a serious way. The hallmark symptoms are redness, a gritty sensation, discharge, and itching. What the discharge looks like tells you a lot about the cause:
- Viral pink eye produces watery, thin discharge. It often shows up alongside a cold or respiratory infection and typically starts in one eye before spreading to the other within a few days.
- Bacterial pink eye produces thick, yellow or green pus that can glue your eyelids shut overnight. It sometimes occurs alongside an ear infection, especially in children.
- Allergic conjunctivitis affects both eyes at once, causes intense itching, and comes with other allergy symptoms like sneezing or a scratchy throat. This type isn’t an infection at all.
Infections deeper in the eye feel different. Keratitis causes significant eye pain, light sensitivity, tearing, and a persistent feeling that something is stuck in your eye. It’s more common in contact lens wearers. Uveitis causes eye pain, light sensitivity, and changes in vision. Neither of these typically produces the heavy discharge that defines pink eye. The key distinction: if your vision is changing or you have real pain (not just irritation), the problem likely goes beyond simple conjunctivitis.
Why the Difference Matters for Treatment
Most cases of viral pink eye don’t need prescription medication. Cold compresses and over-the-counter artificial tears are the standard approach to manage discomfort while the infection clears on its own. A doctor may prescribe antiviral medication for more serious viral strains, such as those caused by herpes simplex or varicella-zoster, but these cases are uncommon.
Bacterial pink eye is treated with prescription antibiotic eye drops or ointment. The antibiotics speed recovery and reduce the window during which you can spread the infection to others. Allergic conjunctivitis responds to antihistamine eye drops and allergy medications, some available over the counter and others by prescription.
Deeper eye infections require more aggressive treatment and close monitoring by an eye specialist. Keratitis may need targeted antibiotic, antifungal, or antiviral drops depending on the cause, and delaying treatment risks corneal scarring that can permanently affect vision. Uveitis often requires anti-inflammatory treatment to prevent damage to internal eye structures. These are not conditions you manage at home with cold compresses.
How Doctors Tell Them Apart
For straightforward pink eye, a doctor can usually make the diagnosis based on your symptoms and a visual exam. The combination of redness, discharge type, and whether one or both eyes are involved points clearly toward viral, bacterial, or allergic conjunctivitis in most cases.
When deeper infection is suspected, the evaluation becomes more involved. A slit lamp exam, which uses a specialized microscope with a bright light, lets the doctor examine the cornea and internal eye structures in detail. If the cause isn’t obvious, a swab of the discharge or a scraping from the affected tissue can be sent to a lab for microscopic examination and culture. This helps identify the specific organism responsible, whether it’s a bacterium, fungus, or parasite, so treatment can be targeted accurately.
When Symptoms Point to Something More Serious
Standard pink eye, while annoying, resolves without lasting effects. But certain symptoms signal that you may be dealing with a more serious eye infection rather than simple conjunctivitis. Sudden vision loss or blurriness, severe pain that over-the-counter medications don’t touch, extreme light sensitivity, double vision, or facial swelling around the eye all warrant prompt evaluation. A high fever paired with eye symptoms is another red flag, as is any new eye pain or vision change following eye surgery or an injury.
Viral pink eye can cause some mild light sensitivity around days three to five, which is normal. But if light sensitivity is severe or accompanied by vision changes, the infection may have spread to the cornea or another structure, and that changes the urgency.
Contagion and Getting Back to Normal
Viral and bacterial pink eye are both highly contagious and spread easily through direct contact, shared towels, or touching your eyes and then touching surfaces. The standard guidance is to stay home from work or school if your symptoms involve close contact with others, and to get clearance from a doctor before returning.
Practicing good hand hygiene, avoiding touching your eyes, and not sharing pillowcases or eye makeup are the most effective ways to prevent spreading conjunctivitis. Allergic conjunctivitis, since it’s not caused by an infectious agent, poses no contagion risk at all. Deeper eye infections like keratitis and uveitis are also generally not contagious, though the underlying organism (in rare cases) could be transmitted through contaminated contact lenses or lens solution.