What's Up Doc? Drooping eyelid needs attention
Q: I think my left eyelid is drooping. At first I thought maybe I had a sty, but I don't think that is really the case. It has been this way for about a week and it has not gotten any better. Any ideas?
A: Ptosis, short for blepharoptosis, is drooping of the upper eyelid. You should see an eye doctor (ophthalmologist) right away to confirm the diagnosis and to be evaluated for it.
The muscles called the levator palpebrae superioris and the Mueller muscle are responsible for lifting the upper eyelid.
The levator muscle attaches to the eyelid by something called an aponeurosis, which is a tendon-like structure, kind of like a ribbon or flattened string, and this muscle does the lion's share of lifting the upper eyelid. The nerve that sends the signal to activate this muscle is called the oculomotor nerve (also called the third cranial nerve).
Part of the sympathetic nervous system - which is responsible for our fight or flight reflex and helps open our eyes extra wide when we are in danger - is responsible for stimulating the Mueller muscle. The nerves that do this leave the spinal cord in the neck (the cervical spine), and after traversing through the upper chest join up with a branch of the third cranial nerve and go to the eye. They then help lift the eyelid extra high (by stimulating the Mueller muscle), widen the pupil opening (so we can see in less light), and make the skin around the eye sweat; all part of the fight or flight response of the body.
The eyelid not rising as it should can be due to the muscles not working or the nerves that should be telling the muscles to lift not working. In either case the net result is that the eyelid is not lifted and a droopy eyelid results.
Ptosis is a very uncommon congenital (meaning a baby is born with it) condition. Although the data I could find on the incidence of this was quite limited, it appears to affect less than 1 in 1,000 babies, and likely much less than this. The droopy eyelid can block the baby's vision and this can lead to amblyopia (lazy eye), so it is very important that a baby with ptosis is evaluated by an ophthalmologist who specializes in children.
Most cases of ptosis are acquired; that is, they develop later in life. Mild droopy eyelids are often just a cosmetic issue; however, more severe ptosis can block part of a patient's visual field, preventing them from seeing normally.
Ptosis is a very common malady in the elderly, but for younger adults acquired ptosis is uncommon and an immediate evaluation for the cause is indicated.
The best way to discuss the possible causes of acquired ptosis is to note whether the ptosis is caused by the muscles or the nerves controlling those muscles being affected.
There are many possible causes of ptosis that make the eyelid droop by directly affecting the muscles that lift the eyelid. In fact, this is the most common cause of acquired ptosis, and the aponeurosis is the part of the mechanical system most often affected. This is usually the cause of ptosis in the elderly and typically affects both eyes; although not always symmetrically, so it will sometimes appear that only one side is affected. This loss of "tone" of the aponeurosis can be considered part of the normal aging process, and hence the reason this is so common in the elderly. If this is only a cosmetic issue and does not block any of the visual field, then no treatment is typically indicated.
Ptosis due to mechanical reasons is also a common complication of eye surgeries. As many as 6 percent of cataract surgery patients (cataract surgery is one of the most common surgeries performed in the U.S.) develop ptosis as a complication of the surgery. Ptosis can occur as a complication of eye surgery in younger patients as well, and one reference I found noted that up to 5 percent to 10 percent of radial keratotomy surgeries are complicated by some amount of ptosis.
Trauma can affect the levator muscle, whether it is from an acute blow to the eye or from long-term repetitious trauma such as chronic eyelid rubbing or from long-term contact lens use (holding the eye open to put the lens in as well as from direct mechanical effects from the lens, more common with hard contact lens use than soft lens use), and this can be a contributing or causal factor in developing ptosis.
Certain muscle wasting diseases, for example myotonic dystrophy, can affect the levator muscle and cause ptosis.
The other major category of causes of ptosis is those that interfere with the signal from the nerves that tell the eyelid to lift.
Anything that interferes with the function of the third cranial nerve can manifest as ptosis. This includes mechanical impingement on this nerve from a tumor or brain aneurysm as well as systemic diseases that can affect nerves such as diabetes, multiple sclerosis, myasthenia gravis (MG) and even botulism.
Horner's syndrome is a condition that includes ptosis from the sympathetic nerve that innervates the Mueller muscle being compromised. The triad of symptoms of Horner's syndrome includes the pupil being small, ptosis and loss of sweating in the skin, all on the affected side. Horner's syndrome can be caused by trauma, including surgical trauma from neck surgeries, as well as from nerve compromise from a tumor or infection (such as tuberculosis) in the upper chest or lungs.
Ptosis that gradually develops in the elderly should be evaluated and then monitored by an ophthalmologist. However, new onset or rapidly changing ptosis can be a symptom of an underlying emergent condition, and so needs to be evaluated immediately. The emergent evaluation will concentrate on the possible underlying severe causes, and so it will be important to note whether the pupil or the muscles that move the eye are also involved - these may indicate a cranial nerve or sympathetic nerve problem. Other clues from the history, such as if the ptosis gets worse later in the day when the patient is fatigued, may point to an underlying medical condition such as MG.
Although MG can respond to medications, so the ptosis will improve with appropriate medical treatment for this disease, most of the other causes of ptosis do not respond to medical treatments and so may require other treatments. These may include special eyeglasses that can help "lift" the eyelid or, more commonly, surgery.
If you develop ptosis, see an ophthalmologist immediately for appropriate evaluation and to determine what, is any, treatment or referral is needed.
Jeff Hersh, Ph.D., M.D., F.A.A.P., F.A.C.P., F.A.A.E.P., can be reached at DrHersh@juno.com.