Study of congenital and hereditary ptosis with special attention to accompanying congenital maldevelopment of the os sphenoidale

Cases of Congenital Ptosis may be divided into the following Categories: -1. Those in which the palpebral aperture is abnormally small, preventing the eyelids from being fully opened. The condition may be accompanied by epicanthus, and there may also be a congenital malformation of the os sphenoidale. There, is rarely external ophthalmoplegia, although paresis of the rectus superior may be present owing to lack of use of that muscle.In this Category it is rare for the condition to be unilateral.2. Those in which the palpebral aperture is of normal dimensions, and . the ptosis is due to paresis of the levator palpebrae superioris. In the majority of such cases there is also external ophthalmoplegia and the commonest cause is maldevelopment of the levator and of the other external ocular muscles involved.Such cases may be unilateral although the unilateral is much less common than the bilateral form.3. Cases due to birth-injury. These are generally unilateral.4. Cases of Jaw-Blinking, or the Phenomenon of Marcus Gunn. There are always unilateral.Ptosis of the upper eyelids may supervene in later life, and this is sometimes hereditary. It may be isolated symptom, or it may be accompanied by chronic external opthalmoplegia. The aetiology of this condition is unknown, but it is suggested that it may be due to a dystrophy of the levator and external ocular muscles