Sentence:  As parents are often opposed to surgery on the normal eye, considerable improvement may be obtained and further surgery deferred or avoided if a maximal aponeurotic resection (Whitnall's sling) procedure with a superior <WSD>tarsectomy</WSD> is performed first. 
Meaning of the word marked with <WSD> tags:  The operation of removing one or more tarsi (plates of connective tissue, one found in each eyelid).