Pathophysiology

Levator palpebrae superioris and Mueller muscle Blepharoptosis are the upper eyelid elevator muscles.
The levator palpebrae superioris originates from orbital apex and continues anteriorly, and at the Whitnall ligament, it travels inferiorly as an aponeurosis. . The aponeurosis inserts into the anterior aspect of the tarsal plate. It also sends attachments to the skin, forming the upper eyelid crease. The levator palpebrae superioris is a striated muscle that is innervated by the superior division of the oculomotor nerve. This muscle is the major elevator of the upper eyelid.
The Mueller muscle, a sympathetically innervated smooth muscle, has its origins from the undersurface of the levator superioris. Approximately 12 mm long, it inserts superiorly on the tarsal border and elevates the upper eyelid by approximately 2 mm.
Blepharoptosis results from dysfunction of one or both upper eyelid elevator muscles.

Diagnosis

History

Patients usually present with complaint of the involved eye being small, tired appearance, limitation of the field of vision, and headache.
Acquired blepharoptosis can occur at any age, but it is commonly seen in older adults. Congenital blepharoptosis presents from birth. There is no racial or gender in predilection blepharoptosis.
More details are needed in regards to the onset of ptosis, alleviating or aggravating factors, family history of ptosis, recent botulinum injection, and history of trauma or ocular surgery. History usually provides very good clue for the etiology of the belpharotposis.
It is important to ask about any anticoagulant use or bleeding, a family history of malignant hyperthermia and cardiac disorders such to avoid potential complications during surgery.
Physical examination

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Signs

Visual acuity and refractive error should be documented. Eye brow position and presence of eyelid extra-skin need to be noted. Careful external examination along with palpation of the eyelids and the orbital rim should be performed. A lid mass can cause extra weight in the lid, resulting in blepharoptosis. Before using topical eye drops, the following measurements need to be done:
 The palpebral fissure, which is the distance between the upper and lower eyelid in vertical alignment with the center of the pupil.
 The marginal reflex distance-1 (MRD-1), which is the distance between the center of the pupillary light reflex and the upper eyelid margin with the eye in primary gaze.
 The marginal reflex distance-2 (MRD-2), which is the distance between the center of the pupillary light reflex and the lower eyelid margin with the eye in primary gaze.
 Levator function, which is the distance the eyelid travel from downgaze to upgaze while the frontalis muscle is held inactive at the brow. A measurement of greater than 10 mm is considered excellent, whereas 0-5 mm is considered poor.
 Presence of eyelid crease and its height.
In patients with unilateral blepharoptosis, the involved eyelid should be lifted manually and the contra-lateral eyelid needs to be observed for any masked blepharoptosis.
Patient needs to be examined for proptosis or enophthalmos, lagophthalmos, and presence of Bell phenomenon.
Ocular motility needs to be evaluated as some patients with blepharoptosis may have limited ocular motility such as in myasthenia gravis and chronic progressive external ophthalmoplegia. Patients with congenital blepharoptosis need to be examined for presence of Marcus Gunn jaw-winking syndrome. The pupillary size and the iris color differences between the eyes should be examined for Horner's syndrome.
It is very important to examine for presence of dry eye with fluorescein stain to examine the cornea, tear meniscus, and tear break-up time.
Sympathomimetic eyedrops can be used to stimulate the Mueller muscle. If a good response is observed, the ptosis may be repaired by Mueller muscle–conjunctival resection.

Diagnostic procedures

Clinical examination is enough in majority of patients. Visual field is usually requested to show the impact of the blepharoptosis peripheral field of vision. In few patients laboratory and imaging studies are needed to find out the cause of the blepharoptosis.

Laboratory test

 Serum assay for acetylcholine receptor antibodies and an edrophonium chloride (Tensilon) test or single-fiber electromyography may be ordered for patients suspected to have myasthenia gravis
 In patients with chronic progressive external ophthalmoplegia, an electrocardiogram, electroretinogram, electromyography, and mitochondrial assay should be considered.

Diagnostic Imaging

 Patients having neurologic deficits along with blepharoptosis should undergo imaging of the brain, orbits, or cerebrovascular system.
 Patients suspected to have inflammatory or infiltrative orbital process as a cause of blepharoptosis need to have orbital CT or MRI scanning.
 In acquired Horner's syndrome, imaging of the head and neck is required.

Differential diagnosis

 Pseudoptosis, which may result from microphthalmos, enophthalmos, anophthalmos, or contralateral eyelid retraction.
 Blepharochalasis
 Brow ptosis
 Dermatochalasis
 Old facial nerve palsy resulting in narrow palpebral fissure
 

Management

Management of blepharoptosis is primarily surgical. Observation is only required in mild cases of congenital ptosis if no signs of amblyopia, strabismus, and abnormal head posture are present. If there is risk for amblyopia, strabismus, and substantial abnormal head posture, surgery is done as soon as possible. Blepharoptosis surgical correction can be done at any time for improving the field of vision or the aesthetic appearance.
If blepharoptosis represents a sign of systemic disease such as myasthenia gravis and Kearns-Sayre disease, the patient should be referred to the appropriate physician for further management.
External photographic documentation is good to obtain especial before attempting surgical correction.

Medical therapy

Patients with myasthenia gravis may improve with medical treatment. Sympathomimetic topical eye drops such as apraclonidine and phenylephrine provide short temporary lift of the upper eyelid in some patients.

Surgery

Surgical correction of congenital ptosis can be done at any age depending on the severity of the disease and early intervention is required if there is a risk for development of amblyopia or significant abnormal head position. Different surgical techniques are available for blepharoptosis correction. Depending on treatment goals, the underlying diagnosis, surgeon preference, and the degree of levator function, the appropriate technique is chosen. Patients need to be aware that symmetry is not easy to achieve. Great care should be taken for patients with dry eyes, decrease corneal sensation, absent Bell phenomenon, double elevator palsy, or progressive external ophthalmoplegia to avoid exposure keratopathy postoperatively. If the patient has strabismus and blepharoptosis, strabismus needs to be corrected first.
Müller muscle–conjunctival resection
This technique is appropriate for patients with mild to moderate aponeurotic blepharoptosis (these patients have very good levator function). This surgery doesn’t work that good for patients with congenital blepharoptosis even with good levator function as the levator palpebrae superioris muscle is not normal. Good response to sympathomimetic topical eye drops provides a good indicator for the success of this type of surgery. This technique has the least chance of changing the eyelid contour compared with the other surgical techniques
The surgery is done from the conjunctival side where, the conjunctiva and the Müller muscle are marked (around 4mm of conjunctiva for 1mm correction of blepharoptosis from the tip of the upper tarsus), the marked conjunctiva and the Müller muscle area is clamped. Suture is passed under the clamp in continuous manner and externalized through the skin at both ends of the marked area, then, tissues above the clamp are resected.
Fasanella-Servat ptosis correction is similar technique. However, it involves resection of conjunctiva, Mueller muscle and part of the upper tarsus.

Levator advancement or resection
This technique involves shortening of the levator aponeurosis according to the severity of blepharoptosis. It works for patients with good and fair levator function
The surgery is done through an eyelid crease incision. The orbital septum may be opened and preaponeroutic fat is retracted away levator aponeurosis. Dissection is done through orbicularis muscle to find the levator aponeurosis. Once it is identified, levator aponeurosis is disinserted from the tarsus and dissection may be continued between levator aponeurosis and Müller muscle. Levator aponeurosis is then advanced and/or resected, and fixed temporarily with 1 to 3 sutures to the tarsus with anterior lamellar bites. The amount of advancement and/or resection depends on the degree of blepharoptosis. If the patient is awake, the lid height and contour are examined at this stage. . Once a good height and contour are achieved, the tarsal lamellar bits are then tightened permanently. The skin is closed with incorporating part of the levator aponeurosis to reform the crease.

Frontalis slings
This is done for patients with poor (<4 mm) or absent levator function. Many autogeneic and allogeneic materials are available be used as a sling. Fascia lata and frontalis muscle flaps, preserved (tissue bank) fascia lata, Gore-Tex suture, frozen dura mater, silicone, and Alloderm have been used. Autogeneous fascia lata was found to give the most favorable surgical result. The sling connects the eye lid with eye brow, and with the elevation of the eyebrow, the eye opens. Following surgery, patients may need several months to be able close their eyelids during sleep. A lot of lubrication is needed during this period.
For patients with unilateral severe blepharoptosis, bilateral frontalis sling provide the best cosmetic outcome. However, it is often difficult to persuade the parents and the patient to perform surgery on the normal contralateral levator muscle.
For patients with Marcus Gunn jaw-winking syndrome, the surgical correction technique of jaw-winking blepheroptosis is controversial. If the jaw-winking is insignificant, blepharoptosis correction alone (with levator advancement or frontalis sling) depending on the severity of the ptosis and levator function may be enough. If the jaw-winking is significant, extirpation of the levator muscle and placement of frontalis sling may be needed.

Surgical follow up

The surgical correction of blepharoptosis is generally done as an outpatient procedure. While the patient is awake, apply cold compresses to the eyelids for 20 minutes every 1-2 hours for 2-3 days to decrease swelling and bruising. A topical antibiotic ointment (with or without a steroid) is given for the patients to be applied on the eye and the incision site twice daily for 5-7 days. For patients who are expected to have postoperative lagophthalmose, excessive lubrication is needed. Patients usually are seen 1 to 2 weeks following surgery. The patients are evaluated for signs of exposure keratopathy, infection, granuloma formation, and overcorrection and undercorrection. Patients with amblyopia, they need to continue amblyopia treatment.