In a human body, 12 cranial nerves are present, which lead directly to various parts of the head, neck, and trunk starting from the brain. The special senses that we have as humans are because of the presence of these cranial nerves. These help us to see, hear, and taste. These 12 cranial nerves are also responsible for controlling the facial muscles and regulating the glands.
The 12 cranial nerves are named and numbered depending on their location/position from the front of the brain to the back. While the first cranial nerve is the olfactory nerve, the last one is called the hypoglossal nerve. In between the first and the twelfth nerve, there are 10 more cranial nerves present. One of them is the third cranial nerve, which is known as the oculomotor nerve. This nerve controls the movement of your eye muscles.
Among the six eye muscles, four are under the control of this third cranial nerve. Your eyes move inward, and up and down with the help of this nerve. It also helps it to rotate. The constriction of the pupil, the ability of your eyes to focus, and the position of the upper eyelid are completely under the supervision of the third cranial nerve.
Oculomotor Nerve Palsy
Until your third nerve is working fine, everything seems perfect but the oculomotor nerve palsy may destruct your easy-going life. It is the disease that leads to the closed eyelid and also causes deviation of the eye from both outward and downward. You are unable to move your eye inward or up and your pupils get enlarged and insensitive to light in many cases of oculomotor nerve palsy. Palsy can either be complete or partial.
In children, however, the third nerve palsy may lead to the development of amblyopia, which can only be treated by patching the unaffected eye. The patching process may require being continued for many years until the child turns 12. Kids suffering from severe palsy may not have binocular vision as well as stereopsis or three-dimensional vision. However, the head is moved in an abnormal position, the binocular vision may be retained in kids.
Third nerve palsy, in some cases, also leads to double vision when they look in a certain direction. It also causes the drooping of the eyelids.
Some of the main causes of oculomotor nerve palsy have been listed below:
- The palsy normally occurs when the nerve is under extreme pressure
- The nerve does not get enough blood supply
- Head injury
- Brain tumor
- High blood pressure
- Aneurysm because of compression
- Herniation because of compression
- Blood vessel disorders
The signs and symptoms that indicate the third nerve palsy are as follows:
- The affected eye turns outward causing double vision
- The eye will move only in the middle when if you look inward
- No up-down movement
- A severe headache
- Less responsive
- Lack of response to light
- Enlarged pupil
The doctors conduct neurological examination and Magnetic Resonance Imaging or MRI to diagnose the oculomotor nerve palsy. CT scan of the brain is yet again an important diagnosis conducted by medical experts.MRI and CT scans are done to find out the exact cause of the disease. Through these tests, the pupil is tested. These two tests are immediately conducted if there is an indication of some serious underlying disease.
In case the cause is a ruptured aneurysm, the MRI or CT scan is unable to detect blood. In that case, other diagnosis methods are applied. These include a spinal tap or lumbar puncture, CT angiography, magnetic resonance angiography or cerebral angiography.
The treatment opted for third nerve palsy completely depends on the cause of it. Emergency treatment is opted for in case a life-threatening disorder causes it. If your palsy is n acquire one, the chances are that it will get resolved sooner or later depending on the cause of the disease. Surgery is prescribed if your third nerve palsy has been there for more than 6 months.
The sooner you get the palsy diagnosed, the better it is. Thus, if you’re experiencing any of the above mentioned symptoms, visit an ophthalmologist immediately.