Ptosis is drooping of the upper eyelid. If severe, it can interfere with vision by covering the pupil of the eye.
Occasionally, ptosis is due to serious causes, mainly diseases affecting the muscles or nervous system. Examination in clinic determines whether tests need to be carried out to look for these conditions.
Myaesthenia gravis is an autoimmune condition affect the neuromuscular junction. The immune system produces antibodies to the acetylcholine receptor. Other facial muscles may be affected. The weakness may vary, being worse at night or after prolonged exercise. A Tensilon test may be necessary to make the diagnosis. I personally would refer you to a neurologist for this test if I thought that myaesthenia gravis was likely.
Third cranial nerve paralysis produces a drooping lid with weakness of some of the other muscles producing eye movement.
The drooping lid is therefore accompanied by diplopia (double vision). The pupil may or may not also be involved. Third cranial nerve paralysis may occur as an isolated entity, but it may indicate more severe problems such as diabetes or cerebral artery aneurysm. I personally would refer you to a neurologist or neurosurgeon if I felt you had third nerve paralysis.
Usually, though, ptosis is benign in nature and amenable to surgical treatment. The type of operation depends on the degree of weakness of the muscle lifting the eyelid (the levator muscle).
Both types of surgery can be done under local or general anaesthetic.
Brow suspension. If the levator muscle is very weak, then the eyelid may have to be suspended from the eyebrow by tunneling material under the skin. You then learn to control the height of the lid by moving the brow up and down. The material used may be fascia from the thigh, or a manufactured material.
Levator shortening. If the levator muscle is a little weak, or if the tendon has slipped, then I can raise the lid by operating on the muscle-tendon complex itself to shorten it.
Side-effects of surgery:
1. Bruising and swelling are very common. They can be reduced by pressure dressings after surgery, and subsequent use of icepacks. Raising the head of the bed also helps.
2. Hang-up: when you look down, the eyelid may not follow the eye as much as it did before.
3. Poor closure: when you blink, or fall asleep, the eye remains partially open and can become dry. In the worst cases, infection of the eye can occur. For this reason, I prescribe drops to be used for three months after surgery with ointment at night. Exceptionally rarely, if the eye becomes compromised, then the lid may have to be lowered again.
4. Unsatisfactory lid height: further surgery may be necessary to raise or lower the lid.
5. Infection is rare. It can be prevented by keeping the wound clean with hydrogen peroxide soaked cotton buds, and treated with antibiotic if it arises.
6. Loss of eyelashes can occur.
Childhood ptosis
If your child has ptosis, I normally defer surgery until the pre-school year in order to allow the tissues to develop. Occasionally it is necessary to operate earlier. This is usually because the droopy lid is causing amblyopia, or lazy eye. The priority then becomes the development of normal vision. Surgery may be necessary at a later date to give a good cosmetic result.
John Pitts is an oculoplastic surgeon in full-time privatepractice in London and Barbados following a substantive NHS consultantposition. He graduated MB ChB from Glasgow University in 1983 and,in 1987, after working in pathology and neurology, he trained in ophthalmologyin Glasgow, Nottingham and London. He has travelled extensively, workingin centres of excellence in Los Angeles, New Orleans, Melbourne, Barbados,Brunei and Vancouver. He has undertaken Fellowship training inoculoplastics at Moorfields Eye Hospital.
