All ptosis procedures may be classified into five groups: (1) simple resection of the skin and/or orbicularis, (2) operations utilizing the superior rectus muscle, (3) operations utilizing the frontalis muscle, (4) operations enhancing the effect of the levator muscle, and (5) procedures which artificially suspend the lid, as in suturing it to the orbital wall.
The first group is without permanent effect, and the fifth group is dangerous in that a lid suspended high enough to correct the ptosis will not protect the cornea and will not follow the eye on looking down.
If an infant has a normal muscle balance and a ptosis operation utilizing the superior rectus muscle is performed, a sufficient impairment of the muscle balance may occur that amblyopia will ensue. This type of procedure also carries with it the risk of corneal exposure. These two complications contraindicate superior rectus procedures in most instances.
BETTMAN JW. A Modification of the Friedenwald-Guyton Ptosis Operation. AMA Arch Ophthalmol. 1956;56(6):819-824. doi:10.1001/archopht.1956.00930040827002