Objective Perimetry in Diseases of the Visual Path in Childhood

Abstract

Abstract: : Purpose: To determine functional aspects in normal and diseased visual path as revealed by electrophysiological studies in children. Method:Having established multifocal VER normal data base in children under the age of 16yrs, to use this as a reference in the study of 8 cases of intrinsic tumours(chiasmal Hypothalamic Gliomas) of the visual path and 12 children with acute progressive optic neuritis (acute demelinating encephalo myelitis (ADEM)).The multifocal VEP was performed with Accumap perimeter. Results: Accurate objective fields of vision were performed in children as young as five years;an age when accurate subjective fields have been almost impossible to record. The fields were displayed as amplitude and latency. The cases with chiasmal Hypothalamic optic gliomas could be accurately followed with repeated fields allowing monitoring of tumour growth and regression.The cases of Optic neuritis showed an unsuspected extent of field loss. Conclusion: Accurate functional studies in children with Chiasmal Hypothalamic Tumours is important.10% of these tumours regress. Recognising spontaneous regression of these tumors avoids need for therapy. This has added impotantance because of the poor natural history with treatment. Recording fields in cases with severe visual loss accompanied by nystagmus remains an unanswered problem.We have not been able to convincingly delineate cases of Supected multiple Sclerosis from ADEM electrophysiologically. Severe visual loss accompanied by nystagmus present an unanswered problem in recording.

Keywords: 623 visual development: infancy and childhood • 393 electrophysiology: clinical • 511 perimetry