STRABISMUS

One eye remains focused on an object while the other deviates. When the deviation is inward towards the nose, it is called esotropia, when the misaligned eye turns outward, it is called exotropia. Strabismus is a relatively common condition that occurs in about 4% of the child population.

Pseudostrabismus is when baby’s eyes appear misaligned, when they are in fact fine. This is often seen in babies having a low nose and wide bridge between the upper and lower eyelids. These features can make a baby seem cross-eyed, when in fact they are normal.

Congenital esotropia occurs within the first 6 months of an infant being born, and is a condition where one or both eyes turn inwards. In order to ensure normal vision development, corrective surgery must be performed before the age of 2. Although the eyelids may also appear abnormal, no special treatment is required because as the development of the child’s face and nose will naturally pull the eyelids into a more normal shape.

Accommodative esotropia is a common form of strabismus, and occurs in children around 2-3 years of age. This condition can be corrected with farsightedness glasses in order to prevent amblyopia and restore normal binocular visual development.

Exotropia is the most common form of strabismus in children found in Korea. This condition results in one eye deviating outward when looking at a distance, although both eyes may align when focusing straight ahead. It commonly occurs just after waking up in the morning, after watching TV for a long time, or when looking far into the distance when tired. If there are signs of amblyopia or a decrease in visual acuity, then surgery should be performed immediately, in less severe cases of exotropia corrective surgery can be performed later when the child becomes 3 or 4 years of age.

In cases of strabismus, the most prominent symptom in the early stages is seeing double, and to overcome this the brain begins to ignore signals from the deviant eye (amblyopia), resulting in loss of visual acuity and bad eyesight. Another observable method a child relies on to overcome double vision is tilting the head to one side or turning it in a particular direction.

In the examination room, visual acuity tests will be administered to precisely measure eye movement and angle of vision. The doctor uses a prism, a blindfold, and flashlight to examine angle of vision in degrees and tests eye movement in different directions to determine any deviation or impediments preventing the eye from moving naturally.

Additionally when examining children, cycloplegic eye drops that temporarily paralyzes the ciliary body are administered, allowing the doctor to fully measure the patient’s vision. Various complex instruments and spectacles are also utilized to examine whether the patient has double vision or only using one eye to see—instead of normal binocular vision.

Misalignment of the eyes is often quite noticeable by family members. However, other warning signs are squinting in the sunlight, having trouble focusing when looking afar, eyes deviating when sleepy and seeming dazed, or complaints of double vision. If these symptoms appear when looking at an object, your child needs an ophthalmic examination as soon as possible. In cases of latent or periodic strabismus, it may be difficult to detect during a medical examination, so parental observation is essential in diagnosing these types of strabismus. Another form called congenital paralytic strabismus, where the face tilts to one side or seems asymmetrical—and it can be observed that the eye remains stationary and cannot gaze in a certain direction.

When treating strabismus, the primary goal is to preserve vision; the secondary concern is correcting the misalignment of eyes; and the third aim is to restore normal binocular vision and visual development, thus preventing amblyopia. The earlier strabismus is detected and treated, the better the results, so it is ill-advised for parents to refrain from having a young child undergo corrective surgery, thinking the problem can be easily corrected when they grow older with an operation.