Table of Contents
What is a sty (stye)?
A sty is a bump that forms on or in the eyelid as the result of a blocked gland. The word sty can also be spelled stye. There are two distinct types of styes: hordeolum and chalazion. Each has different causes and treatments.
A hordeolum is a blockage of one of the sweat glands or oil glands found in the skin of the eyelid, while a chalazion is a blockage of a meibomian gland, which is a special oil gland unique to the eyelids. Meibomian glands secrete an oily material onto the surface of the eye, preventing the water layer of tears from evaporating too rapidly from the eye's surface between blinks. Therefore, poorly functioning meibomian glands can lead to chronic dry eye symptoms.
What causes a sty?
Styes occur when a gland in the eyelid becomes plugged or blocked. This can occur if the gland's opening is obstructed by scar tissue or a foreign substance (makeup, dust) or if there is thickening of the substance produced by the gland, causing the material to flow sluggishly or not at all.
Are styes contagious?
Whether the sty is due to blockage from the outside or sluggish flow from within, styes are not considered contagious.