How To Distinguish Ptosis From Bell's Palsy: An Optical Guide

Ptosis, or drooping of the eyelid, shares some characteristics with Bell's Palsy, a condition that affects facial muscles. If you are not an optometrist or optician, it is easy to confuse the two. If you are an optician or optometrist, but you are new to the field, you may accidentally diagnose ptosis when the problem is Bell's palsy. There are some key differences to help you tell the two disorders apart.


With ptosis, only the eyelid and the eye behind it are affected. The eye often has amblyopia, or "lazy eye" syndrome. If you have ever watched Peter Falk play "Columbo" on TV, you have seen someone with both ptosis and amblyopia. No other muscles in the face are affected, even when the patient is very tired and the eyelid begins to droop to an almost closed position. Most people with ptosis and/or amblyopia have had it most of their lives, or you will see babies and children with it who have not had corrective surgery or glasses. When a younger patient is treated for ptosis, he or she receives a patch to wear over the stronger eye so that the weaker eye gains strength.

Bell's Palsy

Contrary to popular belief, Bell's palsy is not caused by a stroke, although a stroke can cause very similar features in the patient's face. With ptosis, only the muscles around the eye socket are affected. With Bell's palsy, these muscles as well as the muscles on one entire side of the patient's face are affected. The eyelid may droop, like ptosis, or it may remain open and impossible to close. The rest of the face on the affected side almost always droops, giving the patient a sort of bulldog appearance. The cause is typically a nerve inflammation. It comes on very suddenly, and gradually diminishes over time, none of which is anything like ptosis.

Why Patients Might See an Optometrist for Bell's Palsy

It is easy for patients to assume that they suddenly have ptosis because a drooping eyelid is a more common condition than Bell's palsy. A patient with Bell's palsy may see an optometrist to get optical goods to correct the droop, only to discover that he or she does not have ptosis but Bell's palsy instead.  However, it is not a complete waste of time for a patient to seek out optical help because many with Bell's palsy also experience excessive tearing or dry eye and an optometrist can help with those symptoms.