The literal meaning of the word 'ptosis' is downward displacement. In opthalmolgy, ptosis is the medical term for drooping of the upper eyelid. The surgery performed to correct drooping eyelids is called as ptosis surgery or eyelid lift. It is one of the most common disorders found in opthalmogly. A few probable causes for ptosis are birth defect, disease or injury to the eye and old age. When it is present from birth, ptosis is called as congenital ptosis. It can affect children and adults alike. Ptosis can affect one or both the eyes. Like most medical conditions, ptosis too occurs in degrees. When it is mild, it covers the pupils partially. In more severe cases, ptosis causes the eyelid to close the eyes completely.
The eyelid muscles are worked by the levator muscles, Muller's muscles and the frontalis muscle. If the nerve that supplies blood to these muscles (the oculomotor nerve) is affected, the result is ptosis. With an injury or age, these muscles do not function properly, resulting in ptosis. One more factor that can cause ptosis is cataract surgery. It can also be cased due to an injury to the tendon connecting the levator muscle to the eyelid.
The early symptoms of ptosis include eyebrow aching, eyestrain and a difficulty in keeping the eyes open. Fatigue while reading is also a common symptom. In some instances, ptosis may also signal the presence of a more serious underlying neurological disorder.
Ptosis can be broadly classified as:
Congenital ptosis, acquired ptosis (in which classes overlap), or psuedoptosis. Another method of classifying ptosis is myogenic, aponeurotic, neurogenic, neuromuscular, mechanical, neurotoxic, traumatic or pseudoptotic.
By far, the most common reason for ptosis is the weakness of the levator muscles. Ptosis surgery therefore involves tightening of the levator muscles. In cases where the levator muscles are too weak, the eyelids are suspended under the eyelids so that the forehead muscles prop them up.
Ptosis surgery is generally performed as an outpatient procedure under local anaethesia. It takes about an hour to perform.
It is important to understand that weakness of muscles cannot be fully reversed. Therefore, while ptosis surgery will improve the eyelid functionality, it may not exactly restore the working to 100%.