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Nystagmus is a rapid, involuntary and rhythmic eye movement. These trembling, shaking and\u00a0 \u201cdancing\u201d movements usually occur in horizontal or vertical directions.<\/p>\n
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There are congenital and acquired types of nystagmus. The latter presents several subcategories.<\/p>\n
Congenital nystagmus usually occurs between 6 weeks and 6 months of age. From then on, it is considered acquired nystagmus and may demand complementary exams according to your clinical standard. Congenital nystagmus tends to be divided into two groups with clearly different evolution and treatment needs: children with abnormal vision (sensorial nystagmus) and children with normal vision (motor nystagmus).<\/p>\n
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This means that if a child manifests nystagmus during his\/her fist months of life, it is then fundamental to develop clinical evaluation with an experienced Paediatric Ophthalmologist who can evaluate all visual anatomical elements, thus excluding other associated pathologies (like listed above ones) and assuring visual function health.<\/p>\n
Acquired nystagmus comes a bit later, around 6 months, but it may also occur anytime after that. It may have many etiologies \u2013 structural and functional brain anomalies, medication side effects, neoplasms, genetic and metabolic disorders among others. Acquired nystagmus may be associated to severe medical conditions and usually demands an extra evaluation with imaging exams \u2013 such as magnetic resonance imaging \u2013 and auxiliary analytical exams to define a potential cause as well as interdisciplinary supervision like Paediatric Neurology and other medical specialties.<\/p>\n
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It usually happens spontaneously in a child, meaning it was not present in none of the parents. Nevertheless, there are families who have several nystagmus-affected members, which helps us identifying possible relations between genes and nystagmus \u2013 that may have several inheritance forms: dominant, recessive and X-linked. It may also manifest in several ways between family members, meaning they are not absolutely similar between people.<\/p>\n
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Answer differs according to the type of nystagmus! Therefore, clinical evaluation is primordial. If a child suffers from congenital sensorial nystagmus, vision will be damaged and will probably become poor, but not necessarily because of nystagmus: because of the underlying cause that may be (for instance) related to the retina or the optical nerve. Example: a child with bilateral optic nerve hypoplasia (or abnormal optic nerves\u2019 development) will mainly be visually impaired due to the abnormality of optic nerves and not because of subsequent nystagmus. For a child suffering from congenital or idiopathic motor nystagmus, vision may be very good once eyes are healthy and normal.<\/p>\n
Children suffering from nystagmus often see the world in a similar way to other children. It depends on how old they were when disease started. In congenital nystagmus, the world does not seem like \u201cshaking\u201d due to the high neural adaptation ability of brain \u2013 the child was always like this\u2026 In contrast, when it emerges later or as an acquired nystagmus, patients often relate feeling of movement and oscillopsia, an experience characterised by the instability of images captured by visual field.<\/p>\n
Amplitude and speed of an eye movement may vary according to gaze direction. This means that a child suffering from nystagmus may perceive that his\/her eyes move more when looking to the right side and less when looking to the left side (for example). Therefore, once the decreasing of eye movement or trembling is directly related to an improvement in vision stability, that child will turn his\/her head right to allow an easier look to the left side. This is called the \u201cnull point\u201d. Not all nystagmus cases have a null point.<\/p>\n
If there is a vicious head position<\/a> because of this null point, it means child has identified a way of improving vision. Therefore child should not be encouraged or forced to turn head into the opposite direction once it will only decrease visual capacity. You should communicate this fact to your Paediatric Ophthalmologist.<\/p>\n <\/p>\n In most cases, surgery aim is to help relieving a significant abnormal head position or to decrease nystagmus amplitude when there is a null point. In such cases, surgery is recommended once it may improve visual capacity.<\/p>\n <\/p>\n Firstly, it depends on the underlying cause of nystagmus (if there is one) and its treatment. For example, if a child has a refractive error, then eyeglasses prescription<\/a> is fundamental. If a child suffers from congenital cataract, surgery is recommended. Botolinum Toxin may be useful for some individuals suffering from severe and untreatable oscillopsia.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n <\/p>\n American Association for Pediatric Ophthalmology and Strabismus – https:\/\/aapos.org\/glossary\/nystagmus<\/a>;<\/span> <\/p>\nIs it possible to choose surgery?<\/strong><\/h3>\n
What are the available treatments?<\/strong><\/h3>\n
Adapted from:<\/span><\/strong><\/h4>\n
\nAmerican Academy of Ophthalmology – https:\/\/www.aao.org\/eye-health\/diseases\/what-is-nystagmus<\/a><\/span><\/p>\nRead more:<\/strong><\/span><\/h4>\n