Esotropia

Esotropia is the most common form of strabismus in infants, a condition that refers to any misalignment of the eyes. In the case of esotropia, one eye deviates inward toward the nose while the other fixates normally. Exotropia is the condition where one eye deviates outward, away from the nose. Strabismus, also called "cross-eye," occurs in about four percent of all children in the United States. It happens equally in males and females and is sometimes hereditary. Esotropia can also affect teenagers and adults, and it is usually related to systemic conditions such as high blood pressure, diabetes, strokes, or brain injuries.
The brain's ability to see three-dimensional objects depends on proper alignment of the eyes. When both eyes are properly aligned and aimed at the same target, the visual portion of the brain fuses the forms into a single image. When one eye turns inward, outward, upward, or downward, two different pictures are sent to the brain. This causes loss of depth perception and binocular vision.

When does esotropia occur?

• Pseudoesotropia (false esotropia) is actually the physical appearance of cross-eye when the eyes are perfectly aligned. Infants and young children often have a wide, flat nose with a fold of skin at the inner eyelid that makes the eyes appear crossed. This appearance usually disappears as the child grows.
• Congenital or infant esotropia can be present at birth or may develop anytime during the first 6 months of life. Although it is common for an infant's eyes to be intermittently misaligned, if the condition persists beyond the first few months, it should be checked by a physician. One to 2 percent of children have congenital esotropia, and the condition usually does not improve with age. Surgical correction is usually recommended between 6 and 14 months of age.
• Accommodative esotropia is a common form that occurs in farsighted children, usually 2 years old or older. Young children can often overcome farsightedness by focusing their eyes to adjust to the condition, but the effort required for this focusing causes the eyes to cross. Eyeglasses can reduce the focusing effort and sometimes straighten the eyes. In addition, special eyedrops, ointments, and lenses called prisms may also be effective. Eye exercises can also be helpful, especially in older children. Sometimes bifocals can correct the excessive turning in of the eyes for close work.
• Acquired esotropia occurs after infancy. Children who have been farsighted and have not had glasses, or children who were responsive to glasses but later developed an additional eye-crossing, are the most commonly affected. Children with acquired eye-crossing require prompt evaluation and treatment to correct the deviation and to restore binocular vision.

The causes of some forms of esotropia are not fully understood. There are six muscles that control eye movement, four that move it up and down and two that move it side to side. All these muscles must be coordinated and working properly in order for the brain to see a single image. When one or more of these muscles doesn't work properly, some form of strabismus may occur. Strabismus is more common in children with disorders that affect the brain such as cerebral palsy, Down syndrome, hydrocephalus, and brain tumors.

What are the symptoms of esotropia?

Symptoms of esotropia are decreased vision, double vision, and misaligned eyes. Children with esotropia do not use their eyes together and often squint in bright sunlight or tilt their heads in a specific direction to use their eyes together. They may also rub their eyes frequently. Children rarely tell you they are experiencing double vision, although they may close one eye to compensate for the problem. You may also notice signs of faulty depth perception.
When a young child has strabismus, the child's brain may learn to ignore the misaligned eye's image and see only the image from the best-seeing eye. This is called amblyopia, or lazy eye, and results in a loss of depth perception. In adults who develop strabismus, double vision sometimes occurs because the brain has already been trained to receive images from both eyes and cannot ignore the image from the turned eye.

What are the cures for esotropia?

Treatment depends on the type of esotropia. Accommodative esotropia can be treated successfully by correcting a refractive error with glasses, patching to force the use of the less-preferred eye, or other forms of therapy. Congenital and acquired esotropia usually require surgery for proper and permanent correction.
The surgeon makes a small incision in the tissue covering the eye in order to reach the eye muscles. Then either tight inner muscles are placed farther back to weaken their pull, or the loose outer muscles are tightened by shortening their length to allow the eye to move outward. The procedure is usually done under general anesthesia. Recovery time is rapid, and normal activities can usually be resumed within a few days. Following surgery, corrective eyeglasses may be needed and, in some cases, further surgery is required later to keep the eyes straight.

Posted in Eye health