ABSTRACT
The most relevant diseases and syndromes to be considered in the presence of ptosis or eye muscle pareses and some distinguishing features are listed in table 6.3. Some comments are given, but for more details the reader is referred to neurological and neuro-ophthalmological textbooks. Ptosis (3) is diagnosed if the upper-eyelid covers more than 2 mm of the cornea and is caused by a weakness of the m.levator palpebrae or the m.tarsalis superior. If no muscle weakness is involved, but an anatomical variation, either physiologic or pathologic (e.g. after orbital trauma, aberrant regeneration after facial nerve lesion), the condition is referred to as pseudoptosis. (Fig. 6.1)
11 9 2
44 56 12
62 29 31 2 20
If both upper-eyelids are 'drooping' symmetrically it is not always easy to determine whether this is due to muscle paresis. Especially in older people without complaints, the most obvious cause is a displacement of the eyeballs due to the lack of fat tissue. Central innervation may also be deficient in intoxications with sedatives, or in acute large hemisperic lesions, especially of the nondominant side (4). A diagnostic dendrogram of eyelid drooping is given in figure 6.2. The most frequent cause of senile ptosis is probably a dehiscence or disinsertion of the aponeurosis of the m.levator palpebrae, in a minority a degeneration of this muscle. This affection is slowly progressive, bilateral but often asymmetrical. It develops gradually, without external cause or general disease, occasionally occurring after local trauma including eye operations (6% following cataract operation [5]). It may also be the cause of ptosis in younger patients after a long period of wearing hard contact lenses (6). The main features are ptosis with a good levator function, a raised or absent upper lid skin crease and a thinning of the upper lid above the tarsal plate. A history of
increasing ptosis at the end of the day is a common finding and may falsely suggest MG (7). The therapy is surgical correction (8). Another condition in older people is the presence of excessive skinfolds
(dermatochalasis), which is most prominent at the lateral eye margin. (Fig. 6.3) A partial unilateral ptosis may be caused by a denervation of the m.tarsalis superior and relieved by a sympathicomimetic drug (9). In various myopathies, ptosis is slowly developing over years, bilateral, nearly symmetrical and rarely the chief complaint of the patient, except in the chronic progressive external ophthalmoplegia (CPEO). Confusing is the pseudoptosis in extrapyramidal disorders, especially at the onset of the Meige syndrome (10). These patients are not aware of active closure or spasm of the eyelids but report very fluctuating drooping of the eyelids. This may be influenced by 'tricks', such as laying down, vigorous chewing, manual work, or changing of environment. Their complaints are often worse in the course of the day and may react promptly but short-lasting to a new drug, e.g. pyridostigmine per os or Tensilon, as was my own experience. Not exceptionally some blepharospasm is also seen in MG patients with ptosis and the coexistence of MG and Meige has been reported (11).
