Fourth nerve palsy is a condition where the fourth cranial nerve responsible for eye movement is damaged or malformed, causing the affected eye to drift and resulting in double vision. It can be congenital or acquired through head trauma, and surgery is usually required to correct eye placement. Head tilt is a common sign, and diagnosis involves physical evaluation and imaging scans. Surgical repair focuses on regulating the tension of the superior oblique muscle to improve alignment.
Fourth nerve palsy refers to a birth defect or acquired injury of the fourth cranial nerve, which is responsible for eye movement. When the nerve is damaged or malformed, the superior oblique muscle in the skull behind the eye can’t keep it aligned forward. The affected eye tends to drift vertically, horizontally, or both from the center, causing double vision that can only be relieved by tilting the head to one side. Vision problems and self-awareness about the problem can significantly impair a person’s ability to engage in normal daily activities. Surgery is typically needed to correct eye placement and minimize eye strain.
Most cases of fourth nerve palsy are the result of developmental abnormalities in pregnancy. The causes of congenital paralysis are not well understood, and there are no clear connections between paralysis and the maternal use of medications, diet, or other environmental factors. When fourth nerve palsy develops later in life, it is usually due to severe head trauma after a fall from a height or a high-impact car accident. The condition can be unilateral or confined to one side or bilateral, affecting both eyes. Most cases of both congenital and acquired fourth nerve palsy are unilateral.
The eye’s deviation from central alignment is pronounced in some people and very subtle in others. When the eye does not appear to be out of alignment, the primary sign of fourth nerve palsy is a tendency to tilt the head to one side. For example, an infant or child may be observed tilting their head to compensate for distorted double vision. Head tilt is usually consistent with unilateral paralysis, although a child with bilateral problems may adjust the head frequently to try to even out vision.
A doctor can diagnose fourth nerve palsy in a child by evaluating the physical appearance of the eye and determining the degree of head tilt. Imaging scans and electroencephalograms may also be done to look for abnormalities in the muscles, nerves, and other structures in the skull. Accident victims are similarly evaluated before or after treatment for other injuries. After a diagnosis is confirmed, a team of doctors and surgeons can discuss treatment options.
In most cases, a severely damaged or dysfunctional nerve cannot be corrected. Surgical repair instead focuses on regulating the tension of the superior oblique muscle. A surgeon can sever the muscle and reattach it lower on the eye to help pull the organ into better alignment. After successful surgery, head tilt and central vision tend to improve significantly.
Protect your devices with Threat Protection by NordVPN
