title: Visual loss with inner retinal dysfunction, after snake bite: two case reports.
abstract: OBJECTIVE
  To report two cases of visual loss following snake bite.
  
  
  METHODS
  Retrospective review of medical records including history, examination finding, fundus details and investigation reports (visual field, electroretinogram, visual evoked potential and optical coherence tomogram) at two centers.
  
  
  RESULTS
  Two cases of snake bite presented to us with reduction of vision at 1 and 3 months after the incident. The subnormal b wave and abnormal pattern electroretinography in one case pointed at inner retinal dysfunction and neurotoxicity as the cause of visual loss in an apparently normal-looking fundus. The electronegative b wave in the other gave us a clue that the optic atrophy was consecutive (secondary to inner retinal dysfunction due to central retinal artery occlusion).
  
  
  CONCLUSIONS
  When presented late, diagnosis of visual loss secondary to snake bite becomes difficult and puzzling due to the absence of classical findings. Electrophysiological tests in such cases give us important clue to reach at a definite diagnosis.
authors.affiliation: Srimati Kanuri Santhamma Centre for Vitreo-Retinal Diseases, L V Prasad Eye Institute, Kallam Anji Reddy Campus, Hyderabad, India.
authors.forename: Subhadra
authors.initials: S
authors.lastname: Jalali
authors.forename: Tapas Ranjan
authors.initials: TR
authors.lastname: Padhi
authors.forename: Reema
authors.initials: R
authors.lastname: Bansal
authors.forename: Kalyani
authors.initials: K
authors.lastname: Sahoo
authors.forename: Soumavaya
authors.initials: S
authors.lastname: Basu
authors.forename: Annie
authors.initials: A
authors.lastname: Mathai
mesh_terms: D000328:Adult; D001766:Blindness / Q000209:etiology* / Q000503:physiopathology; D004596:Electroretinography; D005074:Evoked Potentials, Visual / Q000502:physiology; D005451:Fluorescein Angiography; D006801:Humans; D008297:Male; D009896:Optic Atrophy / Q000209:etiology / Q000503:physiopathology; D015356:Retinal Artery Occlusion / Q000209:etiology / Q000503:physiopathology; D012164:Retinal Diseases / Q000209:etiology* / Q000503:physiopathology; D055351:Retinal Neurons / Q000502:physiology*; D012189:Retrospective Studies; D012909:Snake Bites / Q000209:etiology* / Q000503:physiopathology; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology; D058609:Visual Field Tests; D014794:Visual Fields; D055815:Young Adult