A guide to making a natural eyelid margin curvature in blepharoptosis surgery

Sir, Blepharoptosis surgery aims to enlarge the palpebral fissure height in patients showing a narrowed fissure (Landa & Bedrossian 2002). The levator aponeurosis (aponeurosis) is fixed to the tarsus in a 2-dimensional plane, so attention needs to be paid not only to the longitudinal direction of fissure enlargement, but also to the horizontal direction, for which part of the eyelid is principally raised by the aponeurosis. We have devised a method to create a natural eyelid margin curvature in blepharoptosis surgery by fixing the position of the centre of the aponeurosis (COA) to the position corresponding to the supra-pupillary point (SPP) when the eye is open. A 66-year-old woman with aponeurotic ptosis underwent blepharoptosis surgery (levator resection) in the right upper eyelid. First, we detached the aponeurosis from the tarsus and the orbicularis muscle. We kept the eyelid open by holding the eyelid margin on the SPP with forceps and marked this point (Fig. 1A). Turning over the upper eyelid, we confirmed the centre of the tarsus (COT) and marked this point on the tarsal surface of the skin side (Fig. 1B). We fixed the COA in different places on the tarsus (the COT or the tarsus of the SPP) in a horizontal direction and observed each curvature of the eyelid margin on eye opening. We fixed the COA at half the height of the tarsus in the longitudinal direction. Normal positional changes of the SPP in the blinking right eye of a 27-year-old woman were observed to further refine our theory. (A) Right eyelid margin raised with forceps. The peak fissure height is located on the SPP, the position corresponding to the supra-pupillary point on eye opening. (B) Outline of the tarsus in the operation field. A string mark indicates the COT. (C) An SPP located more medially. On eye closure, the COT seemed to be located on the centre of the upper eyelid (Fig. 1B, C) while the SPP was located more medially (Fig. 1C). When the COA was fixed to the COT, the peak fissure height was located laterally (Fig. 2A); when the COA was fixed to the tarsus on the SPP, the peak fissure height was located on the position of the SPP (Fig. 2B). (A) Fixation of the COA to the COT. Peak fissure height is located laterally. Note the lateral side of the fissure is raised (lateral triangle). (B) Fixation of the COA to the tarsus of the SPP. Peak fissure height is located on the SPP. Blepharoptosis surgery achieves enlargement of the fissure height but the lateral side is sometimes raised; this is known as the ‘lateral triangle’ (Fig. 2A). A report by Callahan & Beard (1990) described the fixing of the aponeurosis to the medial side of the tarsus, but gave no explanation as to how this method prevented occurrence of the lateral triangle. We consider that the lateral triangle is partially caused by fixing the COA to the tarsus without considering the relationship between the COT and the SPP. When a normal eye blinks (Fig. 3A, B), the SPP is moved inferomedially on eye closing, so the SPP, observed in the centre of the eyelid on eye opening, can move medially on eye closure. As the palpebral fissure is longer than the tarsal horizontal dimension, the SPP is located more medially than the COT (Shore & McCord 1984). When detaching the aponeurosis, as the COA is located above the COT near the SPP on eyelid opening, it is then located laterally to the SPP on eye closure. Accordingly, to make a normal eyelid margin curvature, the COA needs to be fixed inferomedially to the tarsus of the SPP. When the COA is fixed to the COT, the lateral side of the fissure is raised as the upper eyelid moves superolaterally on eye opening, causing the lateral triangle (Fig. 2A). (A) Eyelid on normal eye opening. The SPP is observed just over the pupil. The asterisk indicates the SPP. (B) Eyelid on normal eye closure. Note the asterisk on the SPP and the black dot next to it moves inferomedially on eyelid closure. There is also the concept of ‘tarsal shift’ (Shore & McCord 1984). This describes the condition that arises when the tarsus changes laterally and a peak fissure height is present laterally. However, as the tarsus is then located in the normal position without shifting laterally, ‘lateral triangle’ may be a more appropriate term than ‘tarsal shift’. In blepharoptosis surgery, if attention is paid to the horizontal direction of the fixing position, as well as to the quantity of aponeurotic resection, an aesthetically pleasing curvature can be created for the eyelid margin.