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Strabismus

Shooting It Straight with Strabismus

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Also known as “cross-eyed”, strabismus is a visual condition in which the eyes point in different directions and are not properly aligned. Under normal conditions, the individual isn’t able to align both eyes simultaneously. With strabismus, one eye may turn upward, outward, inward, or downward; while the other eye looks straight ahead. The turn of the eye may come and go or it may be consistent. In addition, the eye that is straight or misaligned may alternate or switch.

Strabismus is a very common condition among children with approximately 4% in the United States being affected — according to the American Association for Pediatric Ophthalmology and Strabismus. In addition to childhood, strabismus can occur later in life. While it can be a genetic eye disorder that runs in families, many have no relatives with the problem. 

People often believe children with the condition will outgrow it. However, this isn’t true. In reality, strabismus left untreated will tend to get worse. Any child who is older than four months whose eyes are not straight all the time should be examined by a doctor of optometry. Let’s take a closer look at strabismus to understand 

What Are the Different Types of Strabismus?

There are several different types of strabismus:

The most common type of strabismus in infants is infantile esotropia, which involves the eye turning inward. Children with esotropia are unable to use their eyes together. 

  • Accommodative esotropia typically occurs in children two and older. This type of strabismus explains when the child’s eyes turn inward when they focus them to see clearly. The crossing can occur when focusing up close, at a distance, or both.
  • Exotropia is a type of strabismus where the eyes or eye turns outward. Exotropia typically happens when the child focuses on distant objects. It can occur sporadically from time to time, or it may happen the child is tired, ill, or daydreaming. Many parents have noticed their child squints a single eye when in bright sunlight.

What Causes Strabismus ?

Eye movement is controlled by six muscles that are connected to the exterior or outside of the eye. In each eye, one muscle is responsible for moving the eye to the left, while another muscle is tasked with moving the eye to the right. The other four muscles work to move the eye down, up, and at an angle. 

For the eyes to focus straight on a single object, the eye muscles must be working together and balanced. The muscles in both eyes must be effectively coordinated for the eyes to move together. All of the muscles are controlled, of course, by the brain. 

With normal vision, both eyes focus on the same spot. Then the brain merges the two pictures into one, 3D image. The 3D image allows us to create accurate depth perception. However, two different pictures are sent to the brain whenever one eye is out of alignment. 

In infants, toddlers, and children; the brain is trained to ignore the image of the misaligned eye and only sees the image presented from the better-seeing or straight eye. This causes the child to then lose depth perception. 

Because of the way the eyes and brain function, adults who develop strabismus will typically have double vision. This is due to the fact the brain has already learned how to receive images from both eyes and is unable to ignore the image transmitted from the turned eye. Children, however, do not see double.  

Strabismus is particularly common for children with disorders and conditions that affect the brain, such as:

  • Down syndrome
  • Brain tumors
  • Cerebral palsy
  • Hydrocephalus
  • Prematurity

Strabismus can also be caused by injuries and cataracts. The majority of children with the condition, however, do not suffer from either. 

What Happens if Strabismus is Untreated? 

Strabismus can cause reduced vision (amblyopia) in the eye that is misaligned. In this case, the brain pays attention to the image presented by the straight eye and then ignores the image presented by the crossed eye. 

When the same eye is consistently ignored throughout childhood, the eye that is misaligned will lose vision power or fail to develop. This condition — strabismic amblyopia — happens in approximately half of children with the strabismus condition.

Treating Amblyopia

Strabismic amblyopia can typically be treated by blurring or patching the stronger eye, which will improve and strengthen the weaker eye’s vision. Whenever this condition is detected during the initial few years of life, treatment is typically successful. If treatment isn’t received, however, amblyopia can become permanent. Simply put, the earlier the condition is treated, the better the vision results will be. 

What Are the Treatment Options for Strabismus? 

Thanks to innovations in technology, there are a range of different treatment options designed to improve eye coordination and alignment. These options include:

  1. Contact lenses or eyeglasses are the only treatment required for some patients with strabismus. 
  2. Prism lenses are special lenses that are thicker on one side than the other. The prisms work to change the way light enters the eye and minimize the amount of turning the eye has to do to view objects. In some instances, the prism can eliminate the turning of the eye. 
  3. Vision therapy can be used to improve eye focusing and coordination. This structured program works to train the brain and eyes to work more effectively together. These strategic eye exercises can help with eye movement problems, eye teaming, eye focusing, and reinforce the brain-eye relationship. Vision therapy can be conducted at home as well as in the optometry’s office. 
  4. Eye muscle surgery is a procedure that can alter the position or length of the eye muscles to make them appear straight. In many instances, those who require eye muscle surgery will need to undergo therapy to prevent the eyes from being misaligned again and to improve coordination.

Contact Keeler OPhthalmic Instruments

For over 100 years, Keeler has been manufacturing cutting edge equipment and empowering optometric professionals to treat conditions like diabetic retinopathy. Contact us today for the premier ophthalmic equipment and instrumentation.

About the Author Eugene VanArsdale

Eugene is the Director of Marketing Communications at Keeler Instruments. He has been with Keeler since 1982 and is co-holder of two patents for the company. Eugene has a true passion for the eye care industry and has dedicated himself to understanding the ins and outs of the optometric and ophthalmic equipment market.