pinkeye
Meaning of pinkeye: Not every red eye is pinkeye, and the causes that are not conjunctivitis at all are the ones that matter.
Definition of pinkeye
Pinkeye is the everyday name for conjunctivitis, inflammation of the conjunctiva, the thin transparent membrane lining the inside of the eyelids and covering the white of the eye. Small blood vessels within that membrane widen and become visible, which is what turns the eye pink or red. Irritation, watering and discharge usually accompany it.
What are the three main causes?
| Viral | Bacterial | Allergic | |
|---|---|---|---|
| Discharge | Watery, thin | Thick, yellow or green | Watery, stringy |
| Itching | Mild | Mild | Intense, the leading complaint |
| Which eye | Often one, then the other | One or both | Almost always both |
| Company it keeps | Sore throat, runny nose | Lids stuck together on waking | Sneezing, seasonal pattern |
| Contagious | Highly | Yes | Not at all |
Appearance alone is an unreliable guide, since all three redden the eye and the categories overlap. The accompanying features carry more information than the redness does.
How does it spread?
The viral form is spread by hands, shared towels, pillows and surfaces, and the virus survives on those surfaces for a considerable time. It commonly travels through households, classrooms and workplaces, which is why an outbreak often appears in clusters. Shedding can continue while the eye is still red, and in some cases beyond it. Bacterial conjunctivitis spreads by the same routes but less readily. The allergic form spreads not at all, being a reaction of the person rather than an infection, though it looks similar enough to be mistaken for one and to prompt unnecessary isolation.
When is a red eye something else?
Conjunctivitis inflames only the surface membrane, so vision stays clear and discomfort is gritty rather than deep. Certain features point elsewhere: real pain rather than irritation, marked sensitivity to light, blurred vision, a pupil that looks different from the other, or redness concentrated in a ring around the colored part of the eye. Those patterns fit inflammation inside the eye, an ulcer or infection of the cornea, or a sudden rise in eye pressure, none of which involve the conjunctiva primarily. Contact lens wear and recent injury also shift the likely explanation away from simple pinkeye.
Also known as
Used in a sentence
The child was evaluated for pinkeye after developing redness and discharge in both eyes.
Good to know
Pinkeye from a virus is far more contagious than pinkeye from an allergy, and appearance alone does not reliably separate the causes, so accompanying features carry most of the information.