116 Chapter 15

Table 15-1 Classification of

Levator maldevelopment (dysmyogenic) ptosis Aponeurotic ptosis (dehisced or disinserted aponeurosis • Simple (defect isolated to levator muscle) secondary to the following) • With superior rectus muscle weakness • Age • syndrome • or other ocular surgery • Congenital fibrosis of the • Local blunt trauma Myogenic (myopathic) ptosis • Blepharochalasis • Oculopharyngeal dystrophy • Chronic (Graves’ disease, allergy, etc) • Chronic progressive external ophthalmoplegia Mechanical ptosis • Muscular dystrophy • Excess lid weight (lid or orbital mass) • Myasthenia gravis • Scarring • Trauma to the muscular levator Pseudoptosis Neurogenic ptosis • Due to lack of posterior support • (third nerve) • Due to hypotropia • Misdirected oculomotor nerve regeneration • Due to • Marcus-Gunn jaw-winking ptosis • Due to malposition • Horner’s syndrome • Ophthalmoplegic migraine

Adapted from Rathbun JE. Eyelid Surgery. Boston, MA: Little, Brown; 1990:203.

Table 15-2 Table 15-3 Amount of Ptosis Levator Muscle Function

Amount of Levator Muscle Ptosis (mm) Classification Function (mm) Classification <2 Mild 15 Normal 3 Moderate >8 Good >4 Severe 5 to 7 Fair <4 Poor

Surgical Procedure Step 4 Step 1 A 4-0 silk traction suture is placed centrally in the After sterile skin preparation and sterile draping, upper eyelid just above the lash line, and the lid the upper eyelid crease is marked at the desired is placed on traction. This is done after the eyelid height so as to be symmetric with the opposite incision is carried to the tarsus so as to not distort upper eyelid crease. the various layers of the anterior lamella. Step 2 Step 5 Local anesthesia is injected subcutaneously along The orbicularis muscle is dissected inferiorly 3 to the eyelid crease and subconjunctivally along the 4 mm to expose the superior tarsus and approxi- superior border of the tarsus. mately 10 mm superiorly to expose the levator apo- Step 3 neurosis and the orbital septum. The skin is incised along the marked eyelid crease Step 6 with a blade. The incision is made deeper through At the medial and lateral ends of the tarsus, scissor the orbicularis muscle to expose the superior bor- incisions are made through the remaining eyelid at der of the tarsus from medial to lateral with scissors the edge of the tarsal border (Figure 15-2). (Figure 15-1).