Congenital Brown syndrome (superior oblique tendon sheath syndrome)

Brown syndrome is a problem with a tendon that attaches to the eyeball. The tendon is called the superior oblique muscle tendon. In Brown syndrome, this tendon can't move freely. This limits the eye's movement. Brown syndrome is a rare disorder. In some cases, it occurs later in life (acquired). But this condition is often present at birth (congenital).

Eye movement is done with muscles and tendons attached to the eye. The superior oblique muscle tendon passes through a small pulley-like structure called the trochlea near the upper inner corner of the eye socket. The tendon normally moves smoothly through this area as the eye moves. In Brown syndrome, a problem involving the superior oblique muscle-tendon-trochlea complex restricts the eye's movement.

Congenital Brown syndrome is caused by problems with the superior oblique muscle tendon or its sheath. The muscle tendon or its sheath might be too short or thick. Experts don't know what causes Brown syndrome. It may be passed down from parent to child. Brown syndrome that's acquired is rare. But it can happen after surgery or trauma, or with an inflammatory disease. Your child may be at greater risk for Brown syndrome if another member of your family has it.

Brown syndrome most often affects only one eye. In rare cases, both eyes are affected. The symptoms can range from mild to severe.

The main sign of Brown syndrome is difficulty moving the affected eye upward when it is turned toward the nose. For example, a child with Brown syndrome in the right eye may have trouble moving that eye upward when looking to the left.

Other signs and symptoms of Brown syndrome include:

• One eye sitting lower than the other when looking straight ahead.
• Eyes that don't line up normally (strabismus).
• Reduced ability to use both eyes together.
• Double vision, although young children may not report it.
• An unusual head position, such as lifting the chin or turning or tilting the head, to help the eyes work together.

If these problems are present from birth, they are often constant. They may improve over time.

Diagnosis begins with a health history and physical exam. This includes a thorough eye exam. It can be hard to diagnose Brown syndrome in a young child. They may have trouble responding to instructions from a healthcare provider during a normal eye exam. Your child may need to see an eye care provider. Your child may also need imaging tests. These can help give more information about the superior oblique muscle tendon.

Treatment of Brown syndrome may vary based on how severe the symptoms are. If your child has only mild symptoms from Brown syndrome, they may not need any treatment right away. Alignment of the eyes may improve with age.

More severe cases of Brown syndrome may need surgery. Your child may be more likely to need surgery if their eyes are out of alignment when looking straight ahead. Your child might also be more likely to need surgery if they have double vision, or if your child has a very abnormal head position. During surgery, the surgeon cuts the superior oblique muscle tendon and uses a device to lengthen it. This can allow the muscle tendon to move normally. The surgery is often a success. But some children need repeat surgery.

Keep track of your child's symptoms. They will need close follow-up care. If symptoms get worse, take your child to their healthcare provider.