If both cause swelling to the lid, how can the doctor tell if it is a chalazion or a sty?
Both cause a swelling to the area on the eyelid, but it is an infection of the eyelash follicle that causes a chalazion. Chalazions tend to occur farther from the edge of the eyelid than sties and tend to “point” toward the inside of the eyelid. Sometimes a chalazion can cause the entire eyelid to swell suddenly, but usually there is a definite tender point. When a chalazion is small and without symptoms, it may disappear on its own. If the chalazion is large, it may cause blurry vision.
