in StemSocial2 months ago

Greetings to all and sundry,

It is a wonderful day today and the start of a wonderful weekend for which many of us if not all are excited about and looking forward to. I do hope you that the week has been gracious to you so far and that you are doing amazing and having a wonderful time.


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As usual i would be taking one topic about the eye for our discussion and for our discussion today we would be looking at the condition known as nystagmus. Stay glued to your screen and i do hope you enjoy the read as always.


The eye undergoes a lot of ocular movements which is critical to our ability to be able to focus on object and perceive what they are as impulses are sent to the brain. The movement of the eye has a lot of systems that come together to ensure that everything is done well.


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Previously we look at one of those systems which included the extraocular muscles and their functions and we came to understand how our eyes are able to move up and down and left and right. There's more to it that would be looked at later including the vergence and versions where both of the eyes are involved at the same time and their synergist and antagonist movements.

These movements have direct link with the various cranial nerves which ensure that things tend to function accordingly, including the trochlear nerve, the oculomotor nerve and abducens nerve, However, there are those movements that we do not control consciously which is regulated by the supranuclear and it ensures that there smoothness in our movement and that vision continues to remain clear for us even in the tracking of objects in motion. This is where nystagmus stems from.


The supranuclear controls highly accurate and smooth eye movements which may almost be undetectable unless one is actually looking for it. The supranuclear ensure simultaneous ocular movements such that the rays from the object continue to fall at the same point in both eyes making vision clear and possible even amidst a fast movement.


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The supranuclear controls the saccadic eye movements which the sudden movement of the eye from one object to another. It ensures that even as you quickly move your gaze from an object closer to you to one a bit farther the objects will remain clear and in focus. No one really think much about this however this movement may be voluntary or involuntary, in both cases the supranuclear does it job just fine.

Another one of its functions which is quite important as we always use it is the smooth pursuit movement. This occurs when we have to track an object in motion in space. And so you following that car far away as it goes or an athlete going round the track, the supranuclear ensures that the object continues to remain at the point on the retina where they can be seen and focused.


Nystagmus is one of the motions that also fall under the jurisdiction of the supranuclear. It is an involuntary rhythmic movement that takes the eye back and forth. It may be physiological or pathological, the physiological process is known as optokinetic nystagmus which occurs when we focus on an object going round or in circulation motion like a fan or a merry-go-round.


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The pathological ones are seen in sensory deprivation nystagmus and motor imbalance nystagmus where due to a pathological condition or anatomical anomaly the eye undergoes involuntary jerky eye movements. Because this is happening not to position an image well within the eye but due to something been wrong it may have detrimental effect on vision.

It is quite common in albinos and may also occur in congenital cataract, optic nerve hypoplasia, aniridia and leber's amaurosis. Not much can be done about the condition unless perhaps it's anatomical cause is correctable through surgery like in the case of cataract where it can be removed to improve the vision.


It is important that should you notice any jerky eye movements with your child which may be persistent, you report to your nearest eye care facility for evaluation. Knowing what may be wrong with him may enable your Optometrist or Ophthalmologist be able to do more for him or her.


As always i would end by reminding us to avoid over-the counter medication, taking our eye health serious and having regular eye examination. Remember that early detection saves sight. I wish you a wonderful weekend, stay safe and have a wonderful time.

Further Reading

Armstrong M. J. (2018). Progressive Supranuclear Palsy: an Update. Current neurology and neuroscience reports, 18(3), 12. https://doi.org/10.1007/s11910-018-0819-5.

Helmchen, C., Machner, B., von der Gablentz, J., Sprenger, A., & Zee, D. S. (2022). Downbeat Nystagmus Is Abolished by Alcohol in Nonalcoholic Wernicke Encephalopathy. Neurology. Clinical practice, 12(5), e129–e132. https://doi.org/10.1212/CPJ.0000000000001138

Wang, G., Wang, M., Wang, Q., Long, Y. L., & Li, S. Y. (2022). [Zhonghua yan ke za zhi] Chinese journal of ophthalmology, 58(11), 929–931. https://doi.org/10.3760/cma.j.cn112142-20220303-00092

Alafaleq, M., Sordello, L., & Bremond-Gignac, D. (2022). Congenital Aniridia and Ocular motility. American journal of ophthalmology, S0002-9394(22)00429-9. Advance online publication. https://doi.org/10.1016/j.ajo.2022.11.003


Great capture of the eye, nice technique.

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Close observation and early detection are key to early treatment and recovery. Thanks for sharing

Thank you too for reading

You are welcome

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