Ptosis (ie, blepharoptosis) can be congenital or acquired. It is important to differentiate congenital ptosis from acquired cases with systemic associations (Table 17-1; see also BCSC Section 7, Oculofacial Plastic and Orbital Surgery). Congenital ptosis is usually caused by decreased levator muscle function. It may be familial. Anisometropic amblyopia and strabismus are common associations.
Table 17-1 Classification of Ptosis
Evaluation of ptosis requires assessment of the upper eyelid crease, the palpebral fissure height, and levator muscle function. In severe congenital ptosis, the eyelid crease is usually absent. The clinician can determine the amount of ptosis by measuring the distance between the upper and lower eyelids and the margin–reflex distance (MRD). MRD1 is the distance from the margin of the upper eyelid to the corneal light reflex when the eye is in primary position. Levator muscle function is assessed by measuring the distance that the upper eyelid moves when the patient shifts from downgaze to upgaze; during measurement, the examiner uses digital pressure on the brow to block recruitment of the frontalis muscle.
Tear function, corneal sensitivity, and the Bell phenomenon should also be evaluated because corneal exposure may occur after surgical repair, should it be necessary. Tear function can be assessed by evaluating the tear lake and tear breakup time, as well as checking for the presence of punctate keratitis. Corneal sensitivity can be assessed by the presence of a blink reflex when the cornea is touched with the tip of a cotton swab. In addition, the clinician should determine whether the globe is microphthalmic or whether a hypotropia is present, as either of these may produce pseudoptosis.
Marked congenital ptosis that obstructs vision must be corrected early in infancy to prevent deprivation amblyopia. Correction of severe ptosis usually requires frontalis suspension because of the lack of levator muscle function. Autologous or allogeneic fascia lata and synthetic material such as silicone rods are some of the materials used for suspension. Autologous fascia, however, cannot be obtained until the patient is 3 or 4 years old. Use of synthetic material or allogeneic fascia lata may lead to higher recurrence rates. Repair of mild or moderate ptosis can usually be performed when the patient is older, although the presence of a compensatory chin-up head position may justify earlier surgery. External levator muscle resection is typically performed for mild or moderate congenital ptosis.
Blepharophimosis–ptosis–epicanthus inversus syndrome
Blepharophimosis–ptosis–epicanthus inversus syndrome (BPES; also referred to as congenital eyelid syndrome or blepharophimosis syndrome) may occur as a sporadic or autosomal dominant disorder with features of blepharophimosis, epicanthus inversus, telecanthus, and ptosis. There are 2 types of BPES, both of which include abnormalities of the eyelid; type I also includes premature ovarian failure. Mutations in the FOXL2 gene have been found in both types. The palpebral fissures are shortened horizontally and vertically (blepharophimosis), levator muscle function is poor, and no upper eyelid fold is present (Fig 17-9). The length of the horizontal palpebral fissure, normally 25–30 mm, is only 18–22 mm in these patients. Repair of the ptosis, usually with frontalis suspension procedures, may be necessary early in life. Because the epicanthus and telecanthus may improve with age, repair of these defects is often delayed.
Figure 17-9 Blepharophimosis–ptosis–epicanthus inversus syndrome. Note telecanthus as well.
Marcus Gunn jaw-winking syndrome
Marcus Gunn jaw-winking syndrome (also known as co-contractive retraction with jaw–eyelid synkinesis syndrome [CCRS], type 5) is a synkinetic syndrome in which the eyelid elevates with movement of the jaw; it may present with ptosis. In Video 17-1, note elevation of the left eyelid with movement of the jaw. The synkinesis is thought to be caused by aberrant connections between the motor division of cranial nerve V and the levator muscle. The clinician may test an infant for this condition by having the child suck on a bottle or pacifier. Many patients do not require treatment. If the ptosis is amblyogenic or a chin-up head position develops, ptosis surgery may be indicated.
Marcus Gunn jaw-winking ptosis.
Courtesy of Mary A. O’Hara, MD.
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Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.