Types of Strabismus
Hidden Strabismus
What are the types of strabismus?
Strabismus is paralytic (slide angle is different in every direction) and non-paralytic (slide angle is the same in every direction), in one eye (only one eye is used) or alternating (both eyes can be used alternately) depending on the fixation status of the eyes, which can be corrected with glasses or surgery. It can be classified according to the sliding direction.
Could it be a congenital slide?
Congenital slides can occur in a period from 3-6 months to 1 year. The slide angle is very high, it can be noticed by almost everyone. This type of slide does not generally develop due to a refractive error (hypermetropia, etc.). Infants may have low or moderate hyperopia, but it does not correct the misalignment, even with glasses. Such slides may be accompanied by upward slides. It is important not to wait and act early in their treatment. Ideally, the slide is surgically corrected in the first 1.5 years. Thus, the baby can continue his life by catching a point of view where he can use both eyes, not just one eye.
What is pseudostrabismus?
Babies' eyes look inward. The reason for this may be that the root of the nose is wider or there is a skin fold (epicanthus) on the inside of the eyelid. Especially in sideways glances, it gives the impression that the child's eye is sliding inward. This condition, which disappears with age, is called pseudostrabismus. The difference between pseudostrabismus and strabismus can only be diagnosed by a doctor. However, it is seen that the corneal light reflections are symmetrical in the examination to be made with the light test. With closure tests, no movement occurs in the eyes. In addition, unilateral exophthalmos, high myopia, and facial asymmetry are other causes of pseudostrabismus.
Why does double vision happen?
In an adult with a slide, the image in one eye falls on the fovea, while in the other it falls on a point outside the fovea. Unlike children, adults cannot ignore or suppress the image from the eye looking to the different side. This causes double vision. The treatment of this is provided by closing one eye, giving special prismatic glasses, or putting the eyes back to the correct position by surgery.
What is lazy eye syndrome (amblyopia)?
The development of vision is a process that continues increasingly after the birth of the child, and this process develops rapidly in the first 2 years. This development continues gradually until the age of 7. If a child cannot use one of his eyes adequately, that eye's vision will not develop. Since the visual system completes its development at the age of 9 at the latest, vision no longer develops after this time. A healthy level of vision in children occurs when both eyes are in a normal position and equal stimulus is delivered to both eyes. Laziness of vision is vision loss due to failure to develop normal vision in one eye during early childhood. It is seen in 2-3% of the population. The most common causes are strabismus, eye disorders (myopia, hyperopia, astigmatism), and rare cataract in children.
Lazy eye syndrome is treated by closing the well-seeing eye for certain periods. Amblyopia can be successfully treated in patients with early diagnosis. The later the treatment starts, the less chance of success.
Remember that the success of treatment of amblyopia depends on the severity of the amblyopia and the age at which treatment is started. Treatment continues until the age of 9. After this age, treatment is no longer successful. For this reason, it is important to have an eye examination in children at the age of 3 and before they start primary school.
Eye slides due to refractive error
Eye slides due to refractive errors occur mostly in the period between 1-1.5 years and 3 years old. In these children with moderate and high hyperopia, the slide can be corrected either completely or partially with glasses. Their stories are typical. The slide may start suddenly or may occur after a fever or fall. They often have a higher number of dioptres in one eye and carry the risk of lazy eye syndrome. Most of these types of slides can be treated with glasses and occlusion therapy. If the slide is not completely corrected and vision deteriorates when both eyes are looked at at the same time, then strabismus surgery may be required for sliding.
Eye slides due to muscle paralysis
Muscle paralysis can be seen after traumas in childhood and infancy, especially after head trauma, difficult births, and high fever. Rarely, it may occur due to tumors, cysts, or structural disorders in the skull. In adults, it can occur after trauma, as well as in diseases related to the central nervous system such as diabetes, thyroid diseases, and MS.
This type of slide typically has double vision and disappears quickly at younger ages, but is permanent in older age groups. Typically, the head is tilted to the side and one eye is squinted. If the eye angle is too high in children, the brain immediately disables the slid eye to eliminate double vision in a short period and laziness begins in that eye. In adults, double vision is present as long as there is a slide and causes head position. Double vision is a condition that makes life very difficult. Most of the slides due to strokes may disappear within a year. Therefore, it is necessary to wait. In this period, no surgical intervention is usually performed, but botox application is frequently applied for the early recovery of the slide and the improvement of double vision. If the eye slide angle is low, double vision can be prevented with special prismatic glasses.
Eye slides in the older age group
Although it is rarely encountered in infancy, it is usually slides of the eye that begins in childhood and adolescence. They are usually seen in the form of outward displacement. They start intermittently, not always sliding occurs when the eye is squinting or looking away. It can be caused by overwork of the external muscles or weakness of the internal muscles. Fixed slides that affect vision in both eyes require surgical intervention. In some cases, orthoptic treatments may be beneficial in intermittent slides.
Special strabismus
Sometimes, there may be congenital structural and functional disorders in the eye muscles or the nerves that move these muscles, and this may lead to slides. If it causes lazy eye syndrome and causes prominent head position, they should be treated to regain vision with both eyes in the child. Glasses, closure, and orthoptic treatments, surgical treatments are applied in these slides when necessary.
Prepared by the Dünyagöz Hospital Editorial Board.
*The content of this page is for informational purposes only. See your doctor for diagnosis and treatment.
Last Update Date: 15.02.2023
