Brown syndrome refers to a rare disorder where one of the six muscles or tendons responsible for lifting the eye upwards, fails to work as it should. The eye has six muscles around it, which help to move it in different directions. With Brown syndrome, this tendon doesn’t move freely and limits the normal movement of the eyes.
The muscle that causes Brown syndrome is called the superior oblique muscle. The superior oblique tendon muscle attaches to a small eye muscle on the outside of the eye. This muscle helps rotate the eye, and pulls it to look down, and toward the midline. It passes through the trochlea, a ring of cartilage. If there is any problem with the system involving the superior oblique-trochlea path, the muscle will not pass through freely. The result is that the affected person is unable to look inwards or outwards. In some cases, one may notice a clicking sensation with inward and upward eye movements.
In most cases, only one eye is affected. The right eye is especially affected in very severe Brown syndrome cases.
Also Known As
- Tendon sheath adherence, superior oblique
- Superior oblique tendon sheath syndrome
Brown syndrome is subdivided into:
- Congenital, where Brown syndrome is present at birth
- Acquired, where the disorder develops later in life. Brown syndrome is linked to other conditions like trauma, eye surgery-related problems, sinus infection, and inflammatory diseases
- Primary Brown syndrome
- Secondary Brown syndrome
The severity of the condition can also be used to classify it into:
- Mild, where the affected eye has a reduced ability to look up
- Moderate, where the eye often moves downward as it moves inward
- Severe, where the affected eye often turns downward when the individual is looking straight ahead
Causes & Risk Factors
The causes of Brown syndrome remain unknown. However, it is thought to occur during the formation of the concerned tendon or its sheath. For instance, abnormalities may involve a short or thick muscle tendon or its sheath at birth.
Another cause may involve problems with the transfer of genetic information from parent to child. A few cases tend to run in families with Brown syndrome while many others have no Brown syndrome history. The disorder tends to affect more women than men.
Signs & Symptoms
The signs and symptoms may depend on which eye is affected. For instance, if the right eye is affected, it cannot look up when both eyes are looking left. An attempt to make this eye movement may cause mild pain. An affected left eye means the patient cannot look up if both eyes are looking to the right. The left eye, in this instance, may be slower than the right eye.
The affected eye has limited ability to move the eye toward the center or outward from the center.
Other symptoms may include:
- Double vision
- Droopy eyelid
- Widening of the eye when looking upward
- Strabismus, where the eyes are not aligned with each other
- In some cases, the eyes may turn outward when the patient is looking up
- With the patient looking straight ahead, the affected eye takes a downward appearance
- The patient tries to focus both eyes by tilting the head in and turning the chin up to compensate for the disorder
The following will assist with diagnosis:
- A history of the person’s health
- A physical exam and complete eye exam
- Imaging tests to view the superior oblique muscle tendon
Treatment depends on the patient’s age, health, symptoms, causes, and severity of the disorder. The condition doesn’t require treatment and will improve over time unless a squint or the need to wear eyeglasses arises. In mild cases, observation or close watching is recommended since the disorder is more likely to go away without treatment. This is especially for children who have eyes aligned when looking straight ahead. The ability to focus both eyes simultaneously and how well the patient can see is monitored. However, Brown congenital syndrome is unlikely to go away on its own.
Sometimes, treating the underlying condition may help. For instance, lupus may be treated with steroids. For Brown syndrome due to trauma or if recently acquired, medications to suppress the immune system such as corticosteroid injections may help. Steroids and non-steroidal medications help deal with inflammation.
Plastic prisms may assist adults who develop the syndrome and have double vision.
Surgery is recommended in severe cases, and if Brown syndrome patients portray:
- Significant diplopia
- Affected binocular vision
- A very abnormal head position
- Eyes not aligned when looking straight ahead
Surgery is not only performed in the affected eye but the other one as well in some cases. The surgeon cuts the superior oblique muscle tendon then lengthens it using a device. The procedure enables normal muscle-tendon movement.
Prognosis & Long-Term Outlook
Brown syndrome goes away in some patients and surgery to correct the syndrome is often successful. In some children, surgery may need to be repeated.
Prevention & Follow Up
The child needs close follow-up care. Parents or caregivers need to watch for symptoms closely.