What is strabismus?
Strabismus is a visual disorder where the eyes do not align correctly. Strabismus usually causes one eye to fixate on an object while the other eye does not fixate causing the misalignment.
The eye has six muscles that control movement. Normally, the eyes receive messages from the brain that cause them to work together so they both point at the same object. For individuals with strabismus, the eyes do not work together. In some cases, the eye that fixates may switch, and the disorder may come and go.
Globally, it is estimated that between 3-5% of all children are diagnosed with strabismus. Although usually diagnosed in children, it can also occur later in life.
What are the different types of strabismus?
There are different types of strabismus, however in all types, one eye fixates on an object while the other eye misaligns. The misalignments are titled as follows:
· An eye that turns in is called esotropia
· An eye that turns out is known as exotropia
· An eye that turns up is titled hypertropia
· An eye that turns down is referred to as hypotropia
Additionally, Strabismus is classified as “comitant” if the problem is present when looking in all directions or “incomitant”, if the problem varies by the direction the eye is viewing.
What causes strabismus?
Strabismus has several different causes, including issues with the eye muscles, the nerves that transmit information to the muscles, or the control center in the brain that directs eye movements. It can also develop due to other general health conditions or eye injuries. Most cases of strabismus are issues in the brain, not the eye muscles themselves. Additionally, a family history of strabismus, uncorrected farsightedness and medical conditions including Down syndrome, cerebral palsy, stroke, or head injury are also risk factors.Enquire with our ophthalmologists.
Did you know?
In 2012, the “Strabismus, Amlyopia and Refractive Error in Singaporean Preschoolers Study (STARS)” recruited 3009 children to identify the risk factors for developing strabismus. It found that family history and refractive errors play an important role in predicting a strabismus diagnosis in young children. Families with a medical history of Strabismus should pay particular attention to eye health.¹
What are the possible complications of strabismus?
Improper eye alignment can lead to several issues including double vision, changes in depth perception, and also poor vision in the turned eye. When the eyes are misaligned, the brain receives two different images. Initially, the two images may create double vision. After an unknown time period, the brain will ignore the image from the turned eye which may lead to permanently reduced vision in that eye. The longer strabismus is untreated, the more challenging it will be to return the vision to normal.
When should I see a specialist for strabismus?
Early detection and treatment of strabismus is very important for optimal treatment. Seek an eye care specialist whenever the eye wanders even for brief periods of time or when looking in one particular direction.
How should I prepare for my appointment?
Adults and adults accompanying their children should bring all necessary information including eye test results, and the family medical history. If glasses have been prescribed, please bring the glasses. If the patient has undergone any procedures or surgeries, you should be prepared to discuss the diagnosis and treatment with the specialist. A list of current and past medications including doses is also important.
How do specialists diagnose strabismus?
A specialist can diagnose strabismus through a thorough eye exam. The specialist will look at how the eyes focus, move and work together. Exams include observing how a light reflects from the patient’s eyes. The specialist will determine if the vision and visual acuity is being affected. You will be asked to look at letters on reading charts, both at a distance and closer to the patient.
In young children or those who cannot speak or read letters, the specialist will use other methods to measure vision. The eye care specialist will look at the internal and external structures of the eyes. Using the test results, the specialist will determine if the patient has strabismus and will discuss treatment options.
What treatments are available for strabismus?
There are several different treatment options including eyeglasses, prisms, vision therapy, or eye muscle surgery. Surgery is often indicated if the turn of the eye is constant or if the turn is significant. Frequently, multiple procedures will need to be performed to achieve perfect alignment of the eyes.
In some cases, the surgery will only address the cosmetic benefits and will not achieve two-eyed vision if the brain does not use the information from both eyes. Post-surgical therapy including eye teaming and tracking may be necessary. If detected and treated early, strabismus can often be corrected with excellent results.Request an appointment with an ophthalmologist today.
 Chia Audrey, Lin XiaoYu, Dirani Mohamed, Gazzard Gus, Dharani Ramamurthy, Quah Boon-Long, Chang Benjamin, Ling Yvonne, Leo Seo-Wei, Wong Tien-Yin, Saw Seang-Mei. Risk Factors for Strabismus and Amblyopia in Young Singapore Chinese Children. Journal of Ophthalmic Epidemiology. 2013, Volume 20