Children with congenital ptosis may develop amblyopia, particularly if the ptosis is unilateral and occludes the pupil. These children should be referred to a pediatric ophthalmologist to determine whether surgical treatment is indicated. Mild-to-moderate ptosis usually is not an immediate threat to vision, but evaluation is important due to its possible association with systemic diseases. Children with new onset of acquired ptosis, particularly if associated with signs of third nerve palsy or orbital mass, should be referred promptly for further evaluation.

What Shouldn’t Be Missed

Acquired ptosis may be the initial sign of a serious underlying disorder, such as a third nerve palsy or an orbital tumor. Prompt diagnosis improves the outcome of most of these disorders (Table 14–1).

• 1. Congenital ptosis. Congenital ptosis is present at birth. It may be unilateral or bilateral, and varies in severity from mild to severe. Congenital ptosis may be familial or associated with an underlying syndrome, but is often an isolated finding in an otherwise healthy child. Severe congenital ptosis requires early repair due to the risk of amblyopia (Figure 14–1A and B).
  
• 2. Myasthenia gravis. Myasthenia gravis is rare, but ptosis is often the presenting complaint. It may be present at birth due to transplacental maternal antibodies, or may be acquired. The hallmark of myasthenia gravis is variability. It is worse when the child is fatigued. Variable strabismus is also commonly present.
  
• 3. Horner syndrome. The ptosis in patients with Horner syndrome is usually mild to moderate. Patients have unequal pupils (smaller on the affected side), and may demonstrate decreased sweating of the brow on the affected side (Figure 14–2). Horner syndrome itself does not cause vision problems. Its importance lies in possible associations with systemic diseases, such as neuroblastoma.
  
• 4. Third nerve palsy. Patients with complete third nerve palsies usually have marked ptosis on the affected side, severe strabismus with the eye out and down, and a larger pupil on the affected side (although the pupil in some patients with congenital third nerve palsy may be smaller) (Figure 14–3). Severe ptosis from a third nerve palsy may cause amblyopia in young patients. The presence of an acquired third nerve palsy requires prompt evaluation.
  
• 5. Eyelid or orbital mass. A large number of eyelid and orbital lesions may cause secondary ptosis. In most eyelid lesions, this is a mechanical effect due to the increased weight of the eyelids, and the etiology is obvious on examination. Early orbital lesions may cause ptosis without marked proptosis, and this possibility should be kept in mind in patients with acquired ptosis.
  
• 6. Pseudoptosis. This may occur for a variety of reasons (Table 14–2).
  
  
  
  • a. Excess brow skin on the affected side may produce mild apparent eyelid asymmetry. This is benign.
    
  • b. Eyelid retraction of the opposite eye. This may be an isolated finding, or a secondary effect of proptosis (usually due to an orbital mass).
    
  • c. Voluntary closure of the eye due to ocular irritation or light sensitivity.
    
  • d. Vertical strabismus, in which the eyelid on the side with the lower eye appears to have ptosis (Figure 14–4A and B).