title: Visual discrimination training improves Humphrey perimetry in chronic cortically induced blindness.
abstract: OBJECTIVE
  To assess if visual discrimination training improves performance on visual perimetry tests in chronic stroke patients with visual cortex involvement.
  
  
  METHODS
  24-2 and 10-2 Humphrey visual fields were analyzed for 17 chronic cortically blind stroke patients prior to and following visual discrimination training, as well as in 5 untrained, cortically blind controls. Trained patients practiced direction discrimination, orientation discrimination, or both, at nonoverlapping, blind field locations. All pretraining and posttraining discrimination performance and Humphrey fields were collected with online eye tracking, ensuring gaze-contingent stimulus presentation.
  
  
  RESULTS
  Trained patients recovered ∼108 degrees2of vision on average, while untrained patients spontaneously improved over an area of ∼16 degrees2. Improvement was not affected by patient age, time since lesion, size of initial deficit, or training type, but was proportional to the amount of training performed. Untrained patients counterbalanced their improvements with worsening of sensitivity over ∼9 degrees2of their visual field. Worsening was minimal in trained patients. Finally, although discrimination performance improved at all trained locations, changes in Humphrey sensitivity occurred both within trained regions and beyond, extending over a larger area along the blind field border.
  
  
  CONCLUSIONS
  In adults with chronic cortical visual impairment, the blind field border appears to have enhanced plastic potential, which can be recruited by gaze-controlled visual discrimination training to expand the visible field. Our findings underscore a critical need for future studies to measure the effects of vision restoration approaches on perimetry in larger cohorts of patients.
authors.affiliation: From the Flaum Eye Institute, University of Rochester, NY.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Cavanaugh
authors.affiliation: From the Flaum Eye Institute, University of Rochester, NY. huxlin@cvs.rochester.edu.
authors.forename: Krystel R
authors.initials: KR
authors.lastname: Huxlin
mesh_terms: D000328:Adult; D000368:Aged; D019575:Blindness, Cortical / Q000209:etiology* / Q000473:pathology / Q000534:rehabilitation*; D004192:Discrimination, Psychological; D053483:Eye Movement Measurements; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D012189:Retrospective Studies; D020521:Stroke / Q000150:complications* / Q000473:pathology; D000071939:Stroke Rehabilitation; D016896:Treatment Outcome; D014793:Visual Cortex / Q000473:pathology; D058609:Visual Field Tests; D014796:Visual Perception