Final answer:
The most common type of acquired blepharoptosis is aponeurotic ptosis, often related to aging or wear and tear. Mechanical, myogenic, and neurogenic ptoses are less common. Thyroid eye disease can cause lid retraction, which is different from ptosis.
Step-by-step explanation:
Most Common Type of Acquired Blepharoptosis
The most common type of acquired blepharoptosis is aponeurotic ptosis. This condition occurs when there is a stretching or disinsertion of the levator palpebrae superioris muscle's aponeurosis, which is the tendon-like structure that elevates the eyelid. This type of ptosis is often associated with aging, but can also result from eye surgery, trauma, or wear and tear due to chronic eye rubbing or contact lens use.
Aside from aponeurotic ptosis, other types such as mechanical, myogenic, and neurogenic ptosis are less common. Mechanical ptosis results from increased eyelid weight due to tumors, edema, or scarring. Myogenic ptosis arises from diseases affecting the muscles (such as myasthenia gravis or chronic progressive external ophthalmoplegia), and neurogenic ptosis is attributed to nerve damage (such as in third nerve palsy or Horner's syndrome).
Conditions such as thyroid eye disease (Graves' disease) can also affect eyelid position, leading to lid retraction or proptosis rather than ptosis, a distinguishing feature that should be taken into account during diagnosis. An image titled 'Proptosis and lid retraction from Graves' Disease' by Jonathan Trobe, M.D. - University of Michigan Kellogg Eye Center (The Eyes Have It), highlights the lid retraction that is distinct from ptosis.