Congenital ptosis is a partial or complete ptosis of the upper eyelid that obscures the pupil due to weakness or mutilation of the levator muscle or congenital hypoplasia of the innervated nerve and nucleus. The incidence is 0.12% and can be unilateral or bilateral, with 75% being unilateral. In mild cases, it affects the appearance of the eye and has a negative impact on psychological and personality development during the child’s growth. In severe cases, the pupil is blocked, which can affect visual development and lead to form-deprived amblyopia (often combined with refractive error), especially in monocular patients, whose amblyopia is deeper and more difficult to correct.
I. Classification of the disease
Depending on the degree of ptosis, it is classified as
1. complete.
2. Incomplete.
According to the characteristics of the disease, it is classified as follows
1. simple ptosis, which accounts for about 77% of cases.
2. with paralysis of the extraocular muscles, such as the superior rectus and inferior oblique muscles, which account for about 12% of cases, with nerve nucleus hypoplasia being the most common.
3. with congenital anomalies of the eyelid or other parts of the eye such as congenital microtia syndrome
4. Marcus-Gunn (central nuclear anomaly association).
II. Pathogenesis
The etiology of congenital ptosis is complex and is mainly divided into.
1. muscular origin: as hypoplasia or deficiency of the levator aponeurosis muscle.
2. neurogenic: including central and peripheral nerve disorders.
Clinical manifestations
Ptosis is classified as mild, moderate, or severe depending on the degree of ptosis. In mild cases, the lid fissures are small and the eyes are dull, and in monocular cases, the size of the two eyes is different.
Differential diagnosis
Congenital ptosis needs to be differentiated from pseudo ptosis due to vertical strabismus, acquired myasthenia gravis, and congenital microphthalmia and ocular atrophy.
In those with vertical strabismus, the lower eye has a similar appearance to ptosis. When the gazing eye is covered and the lower eye is allowed to gaze forward, the lid fissure can open to normal. Microphthalmia and ophthalmoplegia also show ptosis due to the lack of eyelid support and can be confirmed by ancillary testing.
V. Ancillary examinations
The diagnosis of ptosis is not difficult and can be basically confirmed by taking a medical history, observing the appearance of the eyelid, measuring the height of the lid fissure, and examining the eye position and eye movements. In cases of ptosis not present at birth and with symptoms that are mild in the morning and severe in the afternoon, a neostigmine test is required to rule out myasthenia gravis. In cases of suspected microphthalmia, a thorough ophthalmologic examination and imaging tests such as ultrasound or CT are required to confirm.
VI. Disease Treatment
The only treatment for congenital ptosis is surgical correction.
The timing of surgery varies depending on the degree of the disease.
1. Severe ptosis must be surgically corrected early to avoid any impact on visual development.
2. If the ptosis is mild or moderate, similar in both eyes, does not obscure the pupil, and generally does not cause amblyopia, surgery can be delayed or performed under local anesthesia in adulthood.
Since the levator muscle can also gain some development with age after birth, making it less symptomatic, surgery can be scheduled after the age of 3 to 5 years if possible, and some conservative treatment can be taken before surgery to avoid amblyopia. In addition, if the child’s psychological development is taken into account, mild to moderate ptosis may be treated earlier.
Some conditions are not suitable for surgery, such as combined oculoconjunctival palsy, where the child’s eyes cannot turn upward when closed (Bell phenomenon does not exist), and postoperative exposure keratitis is likely to occur, so surgery should be performed with special caution.
There are two main types of surgical approaches.
1. Incomplete ptosis: an upper eyelid muscle strengthening procedure can be performed, including an upper eyelid muscle shortening, upper eyelid muscle folding, and an upper eyelid muscle anterior migration procedure.
2. Complete ptosis: The levator muscle no longer has motor function and can only be used to lift the lid with the help of the frontalis muscle, which includes alternative suspensions and frontalis flap suspensions.
VII. Prognosis of the disease
The more severe the ptosis, the more pronounced the regression will be if the frontalis is suspended with the aid of a substitute. For this reason, surgeons will usually do an appropriate amount of overcorrection depending on the condition to ensure long-term results. However, the result of overcorrection is often the development of transient motor deficits and eye closure disorders in the immediate postoperative period.
In conclusion, no current surgical procedure can perfectly address the deficiencies of an eye with a developmental defect in the eyelid motor muscles, and the choice of surgical approach and volume is a matter of finding a balance between surgical outcomes and reducing the risk of complications.
VIII. Disease follow-up
Outpatient follow-up visits are made every 1-2 weeks in the immediate future, mainly to observe for signs of infection and exposure keratitis. In addition, inversion of the eyelid and conjunctival prolapse can also cause ocular surface damage, and after 1-3 months, eyelid motility and eye closure will improve significantly, so follow-up can be extended at your discretion until the cornea is not exposed at bedtime, or under medical supervision.
Children with combined amblyopia will also continue outpatient follow-up for treatment of amblyopia.
IX. Precautions
1. The skin sutures are usually removed 7-10 days after surgery, during which the surgical incision has not yet healed, so the eye must be avoided when bathing or washing hair to avoid infection of the incision, and swimming is not recommended.
After surgery, you should take antibacterial eye drops as prescribed by your doctor to prevent infection.
3. Special attention should be paid to preventing complications after ptosis surgery. The most common complication is exposure keratitis. Even if Bell’s sign is present in the preoperative examination, the dryness of the ocular surface due to incomplete eye closure during sleep, especially if there is pain recently after surgery, and some children rarely have transient eyes even during the day, are all causes of exposure keratitis. If the cornea is exposed during sleep, eye ointment needs to be applied to protect the cornea from drying out. If the transient is significantly reduced, remind the child to close the eyes, transient or turn the eyes.
4. If it is confirmed in the past that the patient is a keloid, choose surgical treatment with caution.