Congenital ptosis is the presence of a droopy eyelid or eyelids since birth. While it may not be immediately recognized, it usually becomes more noticeable within a few months. It can be unilateral or bilateral. Ptosis can be mild, when the lid partially covers the pupil, or severe, when the lid completely covers the pupil. There is usually a higher position of the ptotic eyelid on downgaze. While the cause of congenital ptosis is often unclear, the most common reason is improper development of the levator muscle. The levator muscle is the major muscle responsible for elevating the upper eyelid. The condition of congenital ptosis is often associated with anisometropia, strabismus and amblyopia, refractive errors, astigmatism, or blurred vision:
- In a series of congenital ptosis cases incidence of amblyopia (lazy eye) was measured to be 20% of which 3% was attributable to droopy eyelid. In the past, the chin elevation posturing was considered a sign of fusion and, thus, indicating a low risk for amblyopia. However, it has recently been shown that the chin elevation does not rule out the presence of significant amblyopia.
- In a series of a113 patients, 31% were found to have strabismus and of these, 3% of the cases were believed to be caused by ptosis that disrupted binocular fusion. Because the superior rectus is often involved, full extraocular motion needs to be carefully evaluated.
In addition, drooping of the eyelid could lead to in an undesired facial appearance. Those with significant ptosis sometimes need to tilt their head back into a chin-up position, lift their eyelid with a finger, or raise their eyebrows in an effort to see from under their drooping eyelid(s). This also applies to adults who have not had surgical repair.
Marcus-Gunn Jaw-winking Ptosis
This type of ptosis does not generally improve with time, but adults/children do tend to learn how to minimize the appearance through modifying their facial expressions. The phenomenon is thought to be due to a congenital misdirection of the fifth cranial nerve fibers into a branch of the third cranial nerve that supplies levator muscle.
In 1883 Marcus Gunn reported an unusual type of congenital ptosis with a peculiar movement of the affected lid. Marcus-Gunn jaw-wink ptosis is an example of synkinesis, an abnormal innervation connecting two groups of normally unrelated muscles. This phenomenon is thought to be due to a congenital misdirection of the fifth cranial nerve fibers into a branch of the third cranial nerve that supplies levator muscle. Patients are classified according to the degree of two parameters in a 3 x 3 matrix to give 9 combinations of ptosis (mild, moderate, severe) in jaw-winking (mild, moderate, severe). Different positions of the matrix correspond to one of several operations which are abdicated for the correction of this defect. Some interesting statistics related to this jaw-winking ptosis are presented below:
- Roughly 75% of patients with Marcus-Gunn syndrome have an associated weakness of the superior rectus.
- Incidence of amblyopia in patients with Marcus-Gunn jaw-winking ptosis is reported to be approximately 35%.
- In a study in 1984 of 64 patients with jaw-winking ptosis, 60% were found to have amblyopia, 60% were found to have strabismus and 25% were found to have anisometropia. Twenty-five percent were found to have a double elevator palsy.
- It has been proposed that the Marcus-Gunn phenomena is secondary to supranuclear etiology. The prevalence of double elevator palsy in this study tends to support the theory of a supranuclear lesion. In this study of 1984, of 71 patients followed for approximately 5 years, they were unable to document any objective improvement in any of their patients; however, they felt that adults were able to control their lid position in excursion of masquerading their jaw-winking phenomenon.
Congenital ptosis is most often treated by ophthalmic plastic and reconstructive surgeons who specialize in disease and conditions affecting the eyelids, lacrimal (tear) system, the orbit (bone cavity around the eye), and adjacent facial structures. At Idaho Eyelid and Facial Plastic Surgery, our ptosis patients will undergo a complete ophthalmic exam with particular attention to visual acuity and motility. Congenital ptosis is treated surgically, with the specific operation based on the severity of the ptosis and the strength of the levator muscle. If the ptosis is not severe, surgery is generally performed when the child is between 3 and 5 years of age (the “pre-school” years). However, when the ptosis interferes with the child’s vision, surgery is performed at an earlier age to allow proper visual development. The surgical procedure is determined by the amount of levator function present and the severity of ptosis. Function is typically categorized as poor (less than 4 mm), fear (5 to 7 mm) and good (more than 8 mm). In cases of severe ptosis in less than 2 mm of levator function, suspension of the lid to frontalis muscle is the procedure of choice.