Abstract Details

Non decussating retinal-fugal fiber is a very rare disorder of isolated absence of optic chiasmal fibers. The clinical hallmark is the presence of a unique infantile seesaw nystagmus. Etiology is unknown but genetic factors have been proposed. Structural and functional Neuroimaging are the gold standard for finalizing the diagnosis. Long term outcomes data are sparse, but some patients will ultimately retain near normal visual acuity. 

To expand the available knowledge of a very rare cause of congenital nystagmus, Non Decussating Retinal-fugal Fiber Achiasmatic Syndrome by adding three patient reports to the current available literature. And also to conduct a review of all previously reported 47 patients in 27 scientific articles and compare their main neuroradiological characteristics. 

Case description:

Case 1: A 6-week-old male term infant was referred to the neurology clinic in consultation for assessing congenital horizontal pendular nystagmus and unilateral torticollis. Brain MRI was arranged and showed complete absence of the optic chiasm with intact optic nerves and optic tracts. 

Case 2: a 4-week-old term female infant with surgically corrected cyanotic heart disease was noted to have rhythmic rotatory eye movements. A concern for epileptic seizures led to neurology service consult and ultimately brain MRI which showed isolated absence of the optic chiasm. 

Case 3: A 34-week-old preterm twin male was reported at term equivalency to have increased fussiness and random eye movements. He was also noted to have small nasal septum cystic mass. MRI was obtained to evaluate for intracranial extension and showed evidence of absent optic chiasm. 

A supplemental summary of those patients intracranial and extracranial findings is attached (Table -1). 

Our reported small case series illustrate the diagnostic value of MRI neuroimaging techniques in cases of Achiasmatic syndrome. Clinical suspicion and appropriate imaging studies are crucial for early, prompt and accurate diagnosis.