Hypertropia is a form of strabismus in which one eye turns upward, putting it out of alignment with the other eye.
Hypertropia may be constant, with the eye turning all the time, or it can be intermittent, with the eye turning only part of the time. Intermittent hypertropia may occur during times of stress or fatigue.
All forms of strabismus are most commonly diagnosed in children, but can also be found in adults. Often, adults are diagnosed with a form of hypertropia that has been latent for their entire lives, but doesn’t show up until late in life. This is called a “decompensated hypertropia.”
Will Children Outgrow Hypertropia or Strabismus?
Children will not outgrow most types of strabismus, including hypertropia. Treatment is usually required in order to avoid potential loss of sight in the affected eye.
What Causes Hypertropia in Children?
- Fourth nerve palsy (also called superior oblique palsy): Hypertropia can sometimes be caused by a weakening of the fourth cranial nerve. This nerve runs directly from the brain to the superior oblique muscle, which controls the movement of the eyeball. In fourth nerve palsy, this nerve is unable to move the eye down to the midline. Infants and children with this condition may be seen to tilt their heads downward when trying to focus on an object. Treating the hypertropia early in life is important because a head tilt can affect the growth of the face and the development of the muscles and bones in the neck. Other symptoms can include eyestrain or a headache.
- Brown syndrome: This condition, a rare form of strabismus, affects the muscles of the eyes. In people with Brown syndrome, the eye does not move properly, and may turn upward when the patient attempts to turn it inward. Hypertropia caused by Brown syndrome usually does not respond to treatment.
- Duane syndrome (also called Duane Retraction Syndrome): In this rare condition, the eye is unable to move outward due to a problem with the lateral rectus muscle (one of the six muscles that move the eye) and the sixth cranial nerve. In some cases treatment may not be necessary, but the condition should be closely monitored. If the eye turn is significant and is affecting vision, surgery is the preferred form of treatment. Surgery does not cure Duane syndrome, but can correct the hypertropia.
- Trauma: Although this is uncommon, hypertropia can also result from trauma to the eye. In some cases, when the eye muscle develops a hematoma (a localized blood clot) after suffering trauma, the hypertropia may resolve on its own. Other kinds of trauma may require treatment in order to reverse the hypertropia.
What Can Cause Hypertropia in Adults?
Most often hypertropia is seen in children. In some cases, however, hypertropia or other forms of strabismus may develop in adults.
- Stroke: In adults, the most common cause of a turning of the eye is a stroke. Hypertropia may occur if the blood vessels that supply the blood to the nerves that turn the eye burst or begin leaking.
- Graves disease (Graves ophthalmology): Hypertropia in adults may occur when thyroid disease affects the muscles in the eye. Upon testing, the thyroid gland could be found to be overactive, underactive, or even normal. This type of hypertropia could be treated with vision therapy or with surgery. Treating the Graves disease does not result in an improvement to the hypertropia.
- Surgical trauma: In rare cases, hypertropia can occur after surgery to repair cataracts. Certain types of trauma to the eye during surgery could result in the eye turning.
- Neurological disorders: Certain neurological disorders can cause the eyes to come out of alignment. In adults, an abrupt turning of the eye could be a result of a brain tumor pressing on the muscles and nerves of the eye. If a tumor is suspected, it is a cause for immediate evaluation and treatment.
- Decompensation of a congenital phoria: As mentioned above, some forms of hypertropia become apparent later in life
What Are the Symptoms of Hypertropia?
The most visible sign of hypertropia is a misalignment of the eyes — one eye may drift above the midline. It may be constant, or it may only show up at certain times.
In infants and small children, it may also be accompanied by a tilt or other movement of the head to correct for the lack of binocular vision (both eyes working together). In acute onset hypertropia, double vision may be a symptom if the patient is old enough to speak.
Complications of Hypertropia You Should Expect
When left untreated, hypertropia (and other forms of strabismus) can lead to lost sight in the affected eye. When one eye is misaligned, as it is with hypertropia, the eyes develop differently, with the stronger eye taking over for the weaker eye.
If the brain is then unable to reconcile the two different images it receives as a result, it begins to ignore the weaker eye. The eyes then do not work together properly, and another condition called amblyopia is the result.
In amblyopia, one eye has poorer vision than the other. People with amblyopia are at risk for losing sight in the healthy eye. Significant sight loss in the healthy eye could result in disability and a decreased quality of life.
What Are My Treatment Options for Hypertropia?
There are several treatment methods for hypertropia. The type of treatment or treatments used will be dependent upon the age of the patient, the cause of the hypertropia, and the risk of potential complications.
- Eyeglasses: Glasses may be used to bring the affected eye back into alignment. In some cases, prisms may also be used.
- Surgery: Surgery on the affected muscles in the eye is one way to treat hypertropia. During surgery, an incision is made on the white of the eye. The muscle causing the hypertropia is detached from the eye and reattached in a position that will help keep the eye at a more midline position and stop it from turning. In some cases the surgery may need to be repeated if it is found that the muscle has not been reattached in the most optimal spot. Potential complications from surgery include scarring on the white of the eye or an overcorrection that causes the eye to move out of alignment in the opposite direction (hypotropia). After surgery, blurred vision and discomfort are common. Most patients can return to regular activity within a week of the surgery.
- Patching: In order to prevent amblyopia, the healthy eye may be patched. This treatment involves putting a patch over the eye that does not have any deviation. This forces the hypertropic eye to become stronger. Problems with the patch include discomfort and a low level of compliance, especially in children. Choosing a patch that is comfortable and aesthetically pleasing can be helpful in getting children to wear the patch for the prescribed time.
How Can I Prevent Hypertropia?
Hypertropia is not preventable. In children, it is important to detect any eye problems before irreversible complications occur. If there is a family history of strabismus, children should be monitored closely and have an eye screening at the age of about six months.
Eye problems are often noticed when children start school, and a thorough eye exam is recommended for preschool-aged children (between the ages of 3 and 5). Any deviation of the eye, even one that is slight or intermittent, should be discussed with a pediatrician and/or an eye care professional.
In adults, an abrupt turning of the eye should be investigated as soon as possible in order to determine the underlying cause. In some cases, hypertropia in adults can indicate a very serious condition that requires immediate attention.