Ptosis

Ptosis is the abnormal drooping of one or both upper eyelids. When it occurs at birth, it is called congenital ptosis. The condition commonly results from weakness of the levator palpebrae superioris muscle which is one of the extraocular muscles. Ptosis is most harmful when it obstructs a developing child's vision and impedes his or her visual development.

Definition & Facts

Ptosis is a sometimes congenital condition that causes one or both upper eyelids to droop or fall lower than normal. This condition can develop in adults and the elderly, in which case it is considered acquired. It may be a result of underlying disease or a result of the aging process.

If ptosis in a child is severe and goes untreated, the child may be deprived of necessary visual input and develop astigmatism and amblyopia both of which involve vision loss. It is important to diagnose and address ptosis as soon as possible to ensure the child avoids these complications.

Symptoms & Complaints

Individuals with ptosis tend to have one eye that is slightly more obscured by the eyelid than the other. In the more serious cases, the eyelid will droop so low that vision will be significantly hindered.

Individuals with ptosis will sometimes attempt to mitigate the issues caused by this condition by either tilting the head so that the drooping eyelid no longer serves as an obstruction, or using the forehead muscles to add extra lift to the eyelid, so that the individual can see more normally. This causes the individual with ptosis to appear to be arching their eyebrows continuously, but it’s a technique that is used to remove the eyelid obstruction.

In addition to these methods of dealing with the condition, individuals with ptosis may even have to use their hands to force the eyelid to a more natural level in order to see.

Causes

Ptosis is usually caused by an impaired muscle that controls the eyelid, which is called the levator muscle. The reasons why the muscle may become impaired are numerous in cases of acquired ptosis. It is less clear why the muscle is impaired in cases of congenital ptosis.

Kearns-Sayre syndrome is a cause of ptosis. It is a type of genetic disorder that causes paralysis of the muscles around the eyes. This type of paralysis is called progressive external ophthalmoplegia. Kearns-Sayre syndrome involves genetic mutations of the mitochondria.

Ptosis can be caused by life-threatening conditions like brain tumors or eye cancer. Certain cancers of the eye socket can cause dysfunction of the levator muscles, leading to the condition. Injury as well as the aging process may also cause ptosis in adults.

In addition to cancers and tumors, neurological disorders such as strokes and nerve damage can lead to ptosis. A common condition associated with ptosis is Horner’s syndrome. Horner’s syndrome can be caused by a stroke or other disorders that affect the central nervous system (brain and spinal cord).

Myasthenia gravis, which is an autoimmune disease can negatively affect how the muscles and nerves communicate with each other; in this case, the loss of muscle and nerve control in and around the eyes leads to ptosis. 

Another condition that can lead to ptosis is diabetes, which affects blood sugar, which in turn can lead to diabetic neuropathy which can then involve damage of the eyes and optic nerves.

Diagnosis & Tests 

Eye examinations will help an optometrist diagnose a drooping eyelid and determine whether or not it is directly affecting the vision. Because untreated ptosis can lead to astigmatism and vision loss among children, testing for the condition is of utmost importance. Typically, a health professional will utilize a simple eye chart to test visual acuity.

Because diabetic neuropathy is a risk factor for the condition, many health professionals will administer a blood test to identify whether or not a patient has either diabetes mellitus type 1 or diabetes mellitus type 2. In addition to this, a doctor can also use the same blood tests to identify any other underlying autoimmune disorder that may be causing ptosis.

Finally, since cancer is a direct albeit rare cause of this condition, a doctor may utilize imaging studies like X-rays to diagnose risk factors if he or she believes cancer may be a potential cause. These X-rays can detect the tumors or the weakening of the levator muscles sometimes even before the condition manifests, allowing for preventative measures to be taken.

Treatment & Therapy

For the most part, the majority of corrective measures to treat ptosis include surgery with the goal being to raise the drooping eyelid and reduce visual obstruction. Surgeries will also aim to ensure the symmetry between the two eyelids. Surgery typically involves elevating the eyelid by tightening the muscles or slinging the muscles from the forehead.

Surgery may attach the eyelid under the eyebrow using a material grafted from the patient's body or a synthetic as a 'sling'. This will allow the forehead muscles to be used to control the vertical movement of the eyelids, rather than the levator muscle group. The surgical removal of excessive tissue around the eyelid may also occur.

Since myasthenia gravis causes ptosis by causing problems in the way muscles and nerves communicate, pharmaceutical therapies like neostigmine and pyridostigmine may be used. These drugs are acetylcholinesterase inhibitors which prevent the breakdown of acetylcholine, a neurotransmitter, thereby stimulating nerve receptors and nerve impulses and resulting in reduced and sometimes eliminated ptosis.

Prevention & Prophylaxis

Since treatment typically involves surgery, the final result may still be asymmetrical eyelids, but if executed correctly, surgery yields positive outcomes for an individual's visual acuity.