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Definition
Ptosis refers to a drooping of the upper eyelid, which may affect one or both eyes to various degrees. In more severe cases, it may partially block vision.
Possible causes and related conditions
Ptosis is usually a congenital abnormality .Other eye problems may occur with the ptosis, such as squint and astigmatism.
It may, however, be the first sign of a more serious neurological disorder, such as
- Horner’s syndrome – caused by injury to part of the nervous system
- Myasthenia gravis – an auto-immune disorder causing weakened muscles which tire easily.
Weakness of the muscles and tendons retracting the upper lid may occur with age. In younger persons, repetitive stretching of the lid to insert contact lenses is thought to play a role.
Injury to the third cranial nerve, which regulates muscles around the eye, can cause ptosis. The injury, mild or severe, may occur anywhere along the path of the nerve from the brain to the eye muscle, and can cause ptosis of varying degrees. Causes of cranial nerve injury can include brain aneurysm, tumour or trauma.
Ptosis may also be a complication of Botox injected for medical or cosmetic purposes.
Treatment
Medical treatment is not successful, except in cases of myasthenia gravis. In these patients, surgery would be considered if ptosis remained disabling after several months of maximal medical therapy. For Botox-induced cases, the problem usually resolves after several months.
For cranial nerve disorders, the underlying problem must be identified and treated if possible.
Surgery remains the treatment of choice for the vast majority of patients. Techniques will vary according to the extent of weakness of the muscle concerned: tightening the muscle may not be enough, and a “sling” procedure may be needed. Surgery aims to give normal vision and symmetry with the normal eye when only one eye needs correcting, though sometimes full symmetry is not possible.
Plastic and reconstructive surgeons often perform this surgery, with a good result.
Complications
The most common complication of surgery is overcorrection, leading to the inability to completely close the eye, and subsequent dry eye and exposure keratopathy.
Bruising and swelling occur with any surgery, and usually resolve in one or two weeks. Bleeding and infection are also recognised risks, but seldom occur. Scarring is usually minimal, and often hidden in the eyelid crease.
(Dr AG Hall, Health24)
