Ptosis

Ptosis (from Greek Ptosis or πτῶσις, to "fall") is a (drooping) of the upper or lower eyelid. The drooping may be worse after being awake longer, when the individual's muscles are tired. This condition is sometimes called "lazy eye", but that term normally refers to amblyopia. If severe enough and left untreated, the drooping eyelid can cause other conditions, such as amblyopia or astigmatism. This is why it is especially important for this disorder to be treated in children at a young age, before it can interfere with vision development.

Ectropion

Ectropion is a medical condition in which the lower eyelid turns outwards. It is one of the notable aspects of newborns exhibiting congenital Harlequin type ichthyosis, but ectropion can occur due to any weakening of tissue of the lower eyelid. The condition can be repaired surgically. Ectropion is also found in dogs as a genetic disorder in certain breeds.

Entropion

Entropion is a medical condition in which the eyelid (usually the lower lid) folds inward. It is very uncomfortable, as the eyelashes constantly rub against the cornea. Entropion is usually caused by genetic factors and may be congenital. Trachoma infection may cause scarring of the inner eyelid, which may cause entropion. In human cases, this condition is most common to people over 60 years of age.

Stye, hordeolum

An external stye (pronounced /ˈstaɪ/), also could be spelled as sty or hordeolum (/hɔrˈdiːələm/) is an infection of the sebaceous glands of Zeis at the base of the eyelashes, or an infection of the apocrine sweat glands of Moll. External styes form on the outside of the lids and can be seen as small red bumps. Internal styes are infections of the meibomian sebaceous glands lining the inside of the eyelids. They also cause a red bump underneath the lid with only generalized redness and swelling visible on the outside. Styes are similar to chalazia, but tend to be of smaller size and are more painful and usually produce no lasting damage. Styes are characterized by an acute onset and usually short in duration (7–10 days without treatment) compared to chalazia that are chronic and usually do not resolve without intervention.