These letters of the alphabet denote ocular motility pattern that have a similarity to the respective letter: in the A-pattern there is (relatively speaking) more convergence when the gaze is directed upwards and more divergence when it is directed downwards, in the V-pattern it is the contrary, in the  λ-, Y- and X-patterns there is little or no strabismus in the middle position but relatively more divergence in one or both of the upward and downward positions, depending on the "shape" of the letter.Types of incomitant strabismus include: Duane syndrome, horizontal gaze palsy, and congenital fibrosis of the extraocular muscles.When the misalignment of the eyes is large and obvious, the strabismus is called large-angle, referring to the angle of deviation between the lines of sight of the eyes. Less severe eye turns are called small-angle strabismus. The degree of strabismus can vary based on whether the person is viewing a distant or near target. Strabismus that sets in after eye alignment had been surgically corrected is called consecutive strabismus. Differential diagnosis
Pseudostrabismus is the false appearance of strabismus. It generally occurs in infants and toddlers whose bridge of the nose is wide and flat, causing the appearance of esotropia due to less sclera being visible nasally. With age, the bridge of the childs nose narrows and the folds in the corner of the eyes become less prominent. Management
Retinoblastoma may also result in abnormal light reflection from the eye.
Diagnosis
Besides the clinical picture, fasting VIP plasma level may confirm the diagnosis, and  CT scan and somatostatin receptor scintigraphy are used to localise the tumor, which is usually metastatic at presentation.Tests include:

Blood chemistry tests (basic or comprehensive metabolic panel)
CT scan of the abdomen
MRI of the abdomen
Stool examination for the cause of diarrhea and electrolyte levels
Vasoactive intestinal peptide (VIP) level in the blood

Treatment
The first goal of treatment is to correct dehydration. Fluids are often given through a vein (intravenous fluids) to replace fluids lost in diarrhea. The next goal is to slow the diarrhea. Some medications can help control diarrhea. Octreotide, which is a human-made form of the natural hormone somatostatin, blocks the action of VIP.The best chance for a cure is surgery to remove the tumor. If the tumor has not spread to other organs, surgery can often cure the condition.For metastatic disease, peptide receptor radionuclide therapy (PRRT) can be highly effective. This treatment involves attaching a radionuclide (Lutetium-177 or Yttrium-90) to a somatostatin analogue (octreotate or octreotide). This is a novel way to deliver high doses of beta radiation to kill tumours. Some people seem to respond to a combination chemo called capecitabine and temozolomide but there is no report that it totally cured people of VIPoma. Prognosis
Surgery can usually cure VIPomas. However, in one-third to one-half of patients, the tumor has spread by the time of diagnosis and cannot be cured. References

Jensen RT, Norton JA. Endocrine tumors of the pancreas and gastrointestinal tract. In: Feldman M, Friedman LS, Brandt LJ, eds.