Final answer:
The drooping of the upper eyelid due to various causes is termed ptosis, and it can result from congenital factors, aging, injury, or diseases like myasthenia gravis and Horner's syndrome.
Step-by-step explanation:
The term for the drooping of the upper eyelid due to paralysis, disease, or congenital condition is ptosis. This condition can affect one or both eyelids and can be present at birth or develop due to various factors such as aging, injury, or medical conditions. For example, myasthenia gravis is an autoimmune neuromuscular disorder that can cause ptosis, as shown in Figure 15.6.5 where treatment with a drug improves eyelid position.
Conditions like Horner's syndrome, which can present with ptosis, may be caused by a tumor in the thoracic cavity affecting autonomic functions. It is important to diagnose and treat underlying causes to manage ptosis effectively. In some cases, surgical intervention may be required.