Spent whole day to understand this eye thingy. ARGH.
Internuclear Opthalmoplegia or ataxic nystagmus. All the same.
Essentially, in this babi, the problem is HORIZONTAL gazing.
IE: the Cranial Nerve 3 and contralateral 6. I dun care, thats how i remember it. To look to the right, i need right CN6 - Lateral rectus, left CN3 - Medial rectus.
And the two nuclei are connected by Medial Longitudinal Bundle.
And that connection, the Medial Longitudinal Bundle, is the crux of the pathology.
So, when you have INternuclear Opthalmoplegia, the affected side/eye cannot gaze INward.
If you ask the patient to look to his left, so now his left eye would gaze outward, and right eye would gaze inward.
But if the lesion is on his right, his right eye is affected, it cannot gaze inward.
SO you have a right eye stays at the middle.
And your left eye, normal unaffected left eye, due to your right eye staring at the middle, it has to come to middle to align with it, but ur head is asking it to go outward, therefore..NYSTAGMUS!
But if you ask the patient to look to his right, the affected eye has no problem to look outward, and the unaffected eye has no problem to look inward as normal.
And there's no problem for affected eyes to gaze inward if you are doing accomodation test.
And, If the affected eye cannot look outward as well, you have this syndrome, called...the One-and-half-syndrome. BODO PUNYA NAMA.
So in conclusion, Affected Side punya eye, stays in the middle, when patient try to gaze inward, unaffected eye nystagmus.
Causes of this Medial Longitudinal Buddle defect or Internuclear Opthalmoplegia or Atazic nystagmus - bapak ar...from now onwards is called the Ang's Palsy, senang kan! babi betul. EMO SIAL.
Answer: If affect one eye - Stroke. If affect two eyes - usually MS.