title: Visual Function 20 Years After Childhood Hemispherectomy for Intractable Epilepsy.
abstract: OBJECTIVE
  To investigate visual function in adults post hemispherectomy in childhood.
  
  
  METHODS
  Noncomparative case series.
  
  
  METHODS
  All participants underwent visual acuity, binocular function, visual field, optical coherence tomography (OCT) of the retinal nerve fiber layer (RNFL), and monocular pattern reversal visually evoked potentials (prVEP).
  
  
  METHODS
  Six adults who had a hemispherectomy in childhood (median 21.5 years postoperative).
  
  
  METHODS
  Comparison was made of visual acuity, visual field height, global RNFL thickness, and prVEP amplitude evoked by full- and half-field stimulation. Comparison of the eye ipsilateral to the side of surgery to the contralateral eye was achieved employing paired t tests to the visual function measures.
  
  
  RESULTS
  All participants had homonymous hemianopia. The residual seeing visual field was constricted in all cases when compared with normative data despite crossing the midline into the blind hemifield in 11 of 12 eyes. This observation was supported by prVEP to stimuli presented in the blind half field. The height of the visual field was smaller in the eye contralateral to the side of surgery compared with the ipsilateral side (P = .047). Visual acuity and RNFL thickness also showed greater diminution in the contralateral eye (P = .040 and P = .0004). Divergent strabismus was found in 4 participants with greater field loss.
  
  
  CONCLUSIONS
  Adults post hemispherectomy in childhood may have better visual function in the eye ipsilateral to the side of the hemispherectomy compared with the contralateral eye. Possible mechanisms of the interocular difference are discussed. Though visual fields and prVEP responses demonstrate evidence of reorganization into the blind half field, they also reveal significant unexpected constriction of the functional field.
authors.affiliation: Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children, London, United Kingdom; Institute of Child Health, University College London, London, United Kingdom.
authors.forename: Sian E
authors.initials: SE
authors.lastname: Handley
authors.affiliation: Cognitive Neuroscience and Neuropsychiatry Section, University College London Institute of Child Health, and Great Ormond Street Hospital, London, United Kingdom.
authors.forename: Faraneh
authors.initials: F
authors.lastname: Vargha-Khadem
authors.affiliation: Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children, London, United Kingdom; Institute of Child Health, University College London, London, United Kingdom.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Bowman
authors.affiliation: Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children, London, United Kingdom; Institute of Child Health, University College London, London, United Kingdom. Electronic address: alki.liasis@gosh.nhs.uk.
authors.forename: Alki
authors.initials: A
authors.lastname: Liasis
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D000069279:Drug Resistant Epilepsy / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D005074:Evoked Potentials, Visual / Q000502:physiology; D005260:Female; D005544:Forecasting; D006423:Hemianopsia / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D038421:Hemispherectomy / Q000379:methods*; D006801:Humans; D008297:Male; D011184:Postoperative Period; D015203:Reproducibility of Results; D012165:Retinal Ganglion Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence; D015348:Vision, Binocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology*; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology*; D055815:Young Adult