Strabismus

Strabismus is the medical term for an eye misalignment or commonly known in the local language as banlag or duling where one eye is not pointing in the same direction as the other eye. Some patients will have no symptoms except for an abnormal eye appearance. However, older patients tend to complain of seeing double, or they tend to close one eye from too much glare, giving rise to the term “squint.”

There are also instances when a child patient is brought in with straight eyes but with an abnormal head posture. This head turn may be the patient’s way to realign the eyes and eliminate the double vision.

Strabismus is common among infants but should disappear by six months of age. This form of strabismus is usually mild and intermittent. Some infants and kids may have an appearance of eye misalignment yet when examined, they are found to have straight eyes. This is called “Pseudostrabismus” or false strabismus. If the misalignment remains constant and persists beyond six months of age, further evaluation by an eye doctor is needed.

The terms used to describe strabismus depend on the direction of the misalignment. Esotropia is an inward displacement of the eyes. Exotropia, on the other hand, is an outward displacement. Hypertropia is a form of vertical misalignment where one eye is displaced upwards. Hypotropia is what you have if the displacement is downwards. It is also common to patients who have a combination of misalignments.

Strabismus may be congenital (inborn) where no other abnormality is present. The presence of abnormalities such as cataracts and disorders of the retina may diminish vision in one eye resulting to a sensory form of strabismus.

Other causes include muscle problems in the eyes that control movements like paralysis, tumors, post trauma, and inflammation. Refractive errors ( eye grade), if left uncorrected, may also cause some imbalances in vision and may lead to misalignment in the eyes.

Evaluation of patients with strabismus involves a thorough eye exam to rule out structural problems that may cause the eyes not to work together. In some cases, neuroimaging tests such as CT-scans or MRI (magnetic resonance imaging) may be needed for a definite diagnosis. Also, getting a good refraction may involve the use of an eye drop given the same day or a few days before the eye consult.

Certain types of strabismus may disappear without intervention, like those seen in infants or due to temporary paralysis. But for those whose strabismus remains constant, early treatment is advised. A misalignment, if left untreated, may lead to loss of depth perception and worsening of vision on the misaligned eye. Structural changes in the eye muscles can make future treatments more difficult. Aside from these, patients with long-standing abnormal head position due to strabismus may develop tightness of neck muscles and distortion of facial features. Patients are also noted to suffer psychological issues from having such eye conditions. Even though treatment can be done at any age, a more favorable response can be achieved if started early.

The treatment is focused initially on improving and restoring balance of vision on both eyes. This may involve surgical management of cataracts and other eye problems that cannot be corrected by glasses. Glasses, however, may be given to improve vision but may need to be adjusted differently, depending on the type of strabismus. If one eye fails to improve to the level of the better eye, additional intervention is given. This can be done by covering the better eye a few hours a day or by giving an eyedrop to blur the better eye and force the weaker eye to work and improve.

Those with on and off eye misalignment may respond well to eye exercises. These exercises aim to improve fusion or the ability of the eye to stay in alignment. Some are given in the clinic, while others can be done at home (manual or via a computer program).

For those who do not respond to the above treatments, surgery is advised. Surgery is usually decided once the alignment is stable after several visits in the clinic. The earlier the surgery is done, the better the chances of restoring the ability of the eyes to work together. The benefits of early surgery include restoration of fusion and depth perception, elimination of an abnormal face turn, and improvement of vision in the misaligned eye. Surgery can also help improve one’s appearance and alleviate the psychological effects of strabismus. Some patients respond well after one surgery, while others may need more to achieve favorable results.

In summary, strabismus is a misalignment of the eyes that is often caused by or leads to an imbalance in vision.

Many respond well to conservative management, but for those who will need further treatment, early surgery may yield better chances of long-term alignment. For more information, please call the St. Luke’s Medical Center Eye Institute II at 723-01010/0301 ext. 5422/4143 (Quezon City) or 7897700 ext. 2024 (Global City).