Definition
Ptosis is a drooping of the eyelid, and although it may occur in the lower eyelid, the term usually refers to the upper eyelid.

The eyelid can be only a little drooped or too drooped, occluding thus partially or totally the pupil. An 
extensive ptosis can restrict or even obstruct vision.

Ptosis may be hereditary and it can affect the upper eyelid of one or both eyes. It may be evident since birth – congenital ptosis, or it may appear later – acquired ptosis.
Both types of ptosis represent an aesthetic and a functional problem, especially in the most severe cases. But congenital ptosis is particularly important and dangerous, as it jeopardizes the normal development of visual function. Most of visual capabilities develop very rapidly during the first months of life, and therefore an obstruction of the visual axis, in this period, can cause visual disorders for life.

Congenital ptosis

It can be the result of several causes. The most frequent is a weakening or a dehiscence of the muscle and/or the aponeurosis that raise the upper eyelid. Normally it is due to an alteration in the development of the muscle itself.

Congenital ptosis may appear as an isolated alteration or it may be associated with other disorders, such as for example: alterations of ocular movements, muscular diseases, eyelid or orbit tumours and some neurological diseases.

Signs and symptoms

The most obvious sign is the existence of a drooped eyelid. In congenital ptosis, there is often an asymmetry of the upper eyelid fold.

Frequently, children with ptosis lean their head backwards and lift their chin in order to uncover the visual axis. Other times, they contract the eyebrows in an attempt to raise the eyelid above the visual axis. These movements of the head and face are indicative signs of the child’s attempt to see simultaneously with both eyes. In time, these vicious positions can cause deformities in the neck and head.

Problems due to ptosis

The visual system develops and matures during the first 6 – 8 years, and it is particularly sensitive to any obstruction of the visual axis in the first months of life. A significantly obstructive ptosis jeopardizes the normal development of eyesight and causes amblyopia (lazy eye).

Ptosis can also condition the occurrence of astigmatism, with a consequent decrease in visual acuity. This astigmatism, if not treated in due time, may contribute for the persistence of amblyopia.

Finally, the presence of ptosis can conceal the presence of strabismus, and thus it can also contribute for the development of amblyopia.

Treatment

The treatment of congenital ptosis is nearly always surgical (98% of the cases). Surgery is advised in case of obstruction of the visual axis by a ptotic eyelid, anomalous position of the head, retardation of the development, or unacceptable alteration of the face.

 

Surgery should be performed during preschool age (3 – 5 years), and even sooner in situations leading to alterations in the development of eyesight. The decision for surgical treatment is based on the severity of ptosis (eyelid height) and its cause. Other relevant factors for this decision are the presence of monolateral versus bilateral ptosis and the presence or absence of alterations in ocular movements.

The most common surgery consists in advancing and/or shortening the elevator muscle of the upper eyelid. However, if the function of this muscle is very insufficient (inferior to 3 millimetres), this surgical technique is not very effective.

Then another technique should be used, consisting in a suture joining the eyelid and the frontal muscle at eyebrow level – frontal suspension. This suture must be made with an appropriate material: the most used are the fascia lata collected in the thigh and a synthetic material of polytrifluoroethylene (PTFE), known as 
Ruban’s ribbon, commercially available. In case of monolateral ptosis, this technique involves some problems of decision, because it creates an asymmetry in the functioning of the two eyelids.

Slight and moderate ptoses may not need surgery during early infancy. In these cases, children should be regularly examined in order to prevent amblyopia, refractive errors and other associated alterations.