Isolated complete bitemporal hemianopia in traumatic chiasmal syndrome

Dear Editor, We read with great interest the article by Kim DW et al.[1] in the previous issue of your esteemed journal. We congratulate the authors for highlighting a rather complex but rather known entity, i.e. the traumatic chiasmal syndrome or the optic chiasmal cleavage syndrome. We share our experience with a report of five cases of blunt head trauma. The patients had no radiologically detected abnormality of the visual pathway, presented to the neuro-ophthalmology clinic at a tertiary eye center, without any neurological signs but had bitemporal hemianopia on visual field examination [Table 1]. Table 1 A profile of the five cases diagnosed with traumatic chiasmal syndrome As rightly pointed out by the authors, those few who survive the impact of chiasmal damage after severe head trauma develop a variety of neurological signs. We found no neurological abnormality in the five cases that we reviewed. Two out of the five had accompanying skull fractures. Literature reports nearly two-third of these patients might have associated skull fractures.[2] Intracranial hemorrhages are also common.[2] As far as the visual acuity is concerned, three out of the five had visual acuity better than 6/12. In the past series described in the literature, nearly 70% patients have good visual acuity (>6/12),[2,3] although some patients may have poor vision. The deteoration in visual acuity depends upon the extent of damage to the anterior visual pathway. Some of these patients may end up with total loss of vision in one eye with temporal loss in the other. All our patients had bitemporal hemianopia due to trauma that was complete as compared with other chiasmal syndromes.[4] Chiasma can be injured in upto 4.4% cases of trauma.[5] In the presence of bitemporal hemianopia, one would expect other neurological abnormalities in the form of cranial nerve palsies and hypothalamus and pituitary abnormalities. However, absence of any such finding, as in our cases, can also be observed.