Ptosis

Ptosis is also called “drooping eyelid.” It is caused by weakness of the muscle responsible for raising the eyelid, damage to the nerves that control those muscles, or looseness of the skin of the upper eyelids.
This problem can have significant functional and aesthetic implications. Because it can be a difficult problem to correct, a variety of procedures have been developed to address ptosis.

Causes
Drooping eyelid can be caused by the normal aging process, a congenital abnormality (present before birth), or the result of an injury or disease.
Risk factors include aging, diabetes, stroke, Horner syndrome, myasthenia gravis, and a brain tumor or other cancer, which can affect nerve or muscle reactions.
Congenital ptosis typically involves isolated myogenic dystrophy resulting in an underdeveloped levator muscle with poor functions. Congenital presentation also can include neurogenic origins such as cranial nerve (CN) III palsy and Marcus-Gunn pupil. Acquired ptosis also can be of neurogenic pathology and include acquired CN III palsy and Horner cervical sympathetic nerve palsy. In older patients, myogenic ptosis is caused by a thinning, lengthening, or, less often, disinsertion of the levatoraponeurosis from the tarsal plate.
In addition, acquired muscular dystrophy, progressive external ophthalmoplegia, and myasthenia gravis all can be causes of late-onset ptosis. With the exception of the neurogenic and myasthenic types of ptosis, levator function is usually good in acquired ptosis. Traumatic ptosis varies according to the location of the injury to the levator muscle or lid mechanism. Mechanical ptosis is due to a tumor, cyst, or enlarged lacrimal gland pushing down the eyelid. Pseudoptosis refers to the drooping lid skin of blepharochalasis (An atrophy of the upper eyelids causing a fold of tissue which often hangs over the eyelid margins) and dermatochalasis (redundancy of the skin of the upper eyelids. It is often associated with a protrusion of fat through a defective orbital septum. The condition occurs usually in old people. In severe cases it may obstruct vision).
Grade of ptosis:
Upper eyelid ptosis is a lowering of the upper eyelid margin in relation to superior limbus. Normally, the eyelid covers 1-2 mm of the upper limbus of the cornea. When the ptotic lid covers enough of the upper limbus or pupil it can result in both functional and aesthetic deformities. The severity of ptosis is classified by determining how much of the upper limbus is covered by the lid margin: mild is 2 mm, moderate is 3 mm, and severe is 4+ mm. Levator function is classified based on the distance of lid margin excursion: excellent is 12-15 mm, good is 8-12 mm, fair is 5-7 mm, and poor is 2-4 mm.

Symptoms
Ptosis of the eyelids can have a subtle presentation and even go unnoticed by the patient. Presenting signs include a high tarsal fold, persistent wrinkles in the forehead due to contraction of the frontalis muscle, and asymmetric elevation of the eyebrows, greater on the affected side. In severe cases, patients complain of restricted visual fields. Patients presenting for cosmetic surgical procedures on the face also may demonstrate some degree of upper eyelid ptosis. In apparently unilateral cases, the “normal” appearing eye is checked by closing the affected one to see if a milder degree of ptosis is noted.

Treatment
If an underlying disease is found, the treatment will be specific to that disease. Most cases of ptosis are associated with aging and there is no disease involved.
Surgery can be done to improve the appearance of the eyelids in milder cases if the patient wants it. In more severe cases, surgery may be necessary to correct interference with vision. In children with ptosis, surgery may be necessary to prevent amblyopia.
Many techniques have been used to correct upper eyelid ptosis. Consider the degree of ptosis and levator function when weighing surgical options. Patients with poor levator function (< 10 mm of excursion) and moderate ptosis (< 3 mm) will likely require suspension of the lid from the frontalis muscle: A frontalis sling, or brow suspension, is where the muscle of the forehead (frontalis muscle) is used to help lift the eyelid by placing a sling of material, either taken from the patient or synthetic, between the forehead and the eyelid. Tissue taken from the patient is called autogenous fascia lata and is a small strip of tendon taken from the leg through little incision just above the knee, on the side of the leg. If the patient is too young to have this done, and a sling or brow suspension is required before the age of 4 years, synthetic material, such as silicone, or prolene, or gortex, may be used instead.Patients with poor levator function but severe ptosis (4 mm or greater) are managed with resection of a segment of the levator muscle. Patients who have good levator function (>10 mm excursion) can obtain long-term correction of the ptosis using plication or shortening of the distal levator muscle aponeurosis. Patients with minor ptosis (< 2 mm) and good levator function (>10 mm excursion) are candidates for the Fasanella-Servatmullerectomy.
In addition, when these patients also are undergoing cosmetic facial surgery, they can be treated successfully with transpalpebral blepharoplasty plication of the levatoraponeurosis. In most of these patients with senile ptosis, simple plication of the levator may suffice.

Anesthesia
Because ptosis correction can be performed under local anesthesia with o without sedation, with proper operative selection there are no specific surgical contraindications to surgery. Patients who are undergoing concomitant procedures may require general anesthetic; in these patients, careful preoperative evaluation with regard to the degree of ptosis and planned correction is required.

Possiblecomplications:
Bruising of the eyelids and around the eye.
A small risk of infection of the eyelid or the eye.
Possibility of under-correction or over-correction of the eyelid height, requiring a second operation.
Unable to close the eyelid completely, with the eye slightly open at night.