Ptosis, commonly known as a drooping eyelid, is a condition where the upper eyelid sags or droops, potentially covering part of the pupil and obstructing vision. It can affect one eye (unilateral ptosis) or both eyes (bilateral ptosis) and can be present at birth (congenital) or develop later in life (acquired).
Causes:
Ptosis occurs due to weakness or damage to the muscles that lift the eyelid (levator palpebrae superioris muscle) or the nerves that control them, or due to issues with the eyelid’s supporting structures. Causes vary depending on whether it’s congenital or acquired:
- Congenital Ptosis (present at birth):
- Poor development of the levator muscle: This is the most common cause, where the muscle responsible for lifting the eyelid doesn’t develop properly.
- Genetic factors: Can sometimes be inherited.
- Acquired Ptosis (develops later in life):
- Aponeurotic Ptosis (Involutional Ptosis): The most common acquired type, caused by stretching, thinning, or detachment of the levator aponeurosis (the tendon that connects the levator muscle to the eyelid) due to aging.
- Neurological Conditions: Damage to the nerves controlling the eyelid muscles:
- Oculomotor nerve palsy (third nerve palsy): Damage to the nerve that controls several eye muscles, including the levator.
- Horner’s Syndrome: Damage to sympathetic nerves that affect the eye and face.
- Myasthenia Gravis: An autoimmune disease that causes muscle weakness, including the eyelid muscles.
- Stroke or brain tumor: Can affect nerve pathways.
- Muscle Diseases (Myogenic Ptosis): Conditions that directly affect the eyelid muscles:
- Oculopharyngeal Muscular Dystrophy.
- Chronic Progressive External Ophthalmoplegia (CPEO).
- Trauma: Injury to the eyelid or eye muscles.
- Tumors: Tumors in or around the eyelid can cause drooping.
- Inflammation/Swelling: Swelling from infection, inflammation, or allergic reactions can temporarily cause ptosis.
- Complication of eye surgery: Rarely, ptosis can occur after cataract or other eye surgeries.
Symptoms:
The primary symptom of ptosis is a visible drooping of the upper eyelid. Other symptoms may include:
- Reduced field of vision: The drooping eyelid can block part of your vision, especially your upper field of vision.
- Eyestrain: Due to the effort of trying to lift the eyelid.
- Head tilt or eyebrow raise: Children and adults may tilt their head back or constantly raise their eyebrows to see better, which can lead to neck pain or headaches.
- Asymmetry of the eyes: One eye may appear smaller than the other.
- Fatigue of the eyelids: Eyelids may feel heavy.
- Amblyopia (lazy eye): In children, severe ptosis that obstructs vision can lead to amblyopia if not treated early.
Diagnosis:
Diagnosing ptosis involves a comprehensive eye examination by an ophthalmologist, often with specialized tests:
- Detailed medical history: The doctor will ask about the onset of symptoms, any associated conditions, medications, and family history.
- Physical examination of the eyes and eyelids:
- Measurement of eyelid height (marginal reflex distance – MRD).
- Assessment of levator muscle function (how well the eyelid lifts).
- Evaluation of eye movements and pupil size.
- Slit-lamp examination: To examine the eye structures in detail.
- Visual field testing: To assess if vision is obstructed.
- Blood tests: To rule out underlying systemic conditions like Myasthenia Gravis or other muscle/nerve disorders.
- Imaging studies: MRI or CT scans may be ordered if a neurological cause, tumor, or other structural abnormality is suspected.
- Tensilon test: If Myasthenia Gravis is suspected, a medication called Tensilon (edrophonium) may be injected to see if it temporarily improves eyelid lift.
Treatment:
Treatment for ptosis depends on the cause, severity, and whether vision is affected.
- Observation: For very mild cases that don’t affect vision or are temporary, observation may be sufficient.
- Addressing the underlying cause: If ptosis is due to a treatable medical condition (e.g., Myasthenia Gravis, infection, tumor), treating that condition may resolve or improve the ptosis.
- Medications: For certain neurological causes (e.g., specific eye drops for Horner’s syndrome).
- Ptosis Crutch: A non-surgical option where a small attachment is added to eyeglasses to hold the eyelid up. This is a temporary solution and not suitable for everyone.
- Surgery: This is the most common and effective treatment for persistent ptosis, especially when vision is affected or for cosmetic reasons.
- Levator Resection/Advancement: The most common surgery, where the levator muscle is tightened or reattached to lift the eyelid.
- Frontalis Sling: For severe ptosis or very poor levator function, the eyelid is connected to the eyebrow muscles, allowing the eyebrow to lift the eyelid.
- Müller’s Muscle Conjunctival Resection: For mild ptosis, a small muscle inside the eyelid (Müller’s muscle) is shortened.
The goal of ptosis surgery is to achieve a good functional and cosmetic outcome, ensuring clear vision and a symmetrical appearance. In children with congenital ptosis, early surgery may be necessary to prevent amblyopia.
