Which ocular condition involves a "chalazion" or "stye"?

The term "chalazion" refers to a cyst that forms in the eyelid due to the blockage of a meibomian gland, which produces the oil component of tears. When this gland becomes obstructed, it results in a painless bump or swelling in the eyelid. This is distinct from a "stye," which is an infection of the eyelash follicle or the oil glands associated with it, typically presenting as a tender, red bump.

Eyelid cysts, including chalazia and styes, fall under the broader category of conditions that affect the eyelid structure and can provide insight both into their symptoms and their underlying causes. Understanding these conditions requires awareness of their anatomical locations and functional implications within ocular health.

In contrast, the other conditions mentioned—such as cataracts, conjunctivitis, and retinal detachment—do not involve the formation of eyelid lumps or bumps but instead pertain to various other ocular structures and issues, such as clouding of the lens, inflammation of the conjunctiva, and separation of the retina from the underlying tissue respectively.