Visual Restoration for Hemianopia

Inclusion criteria

• Ages 21-75 years old
• Ability and willingness to sign informed consent
• Willingness to participate in both the training and evaluation sessions
• MRI or CT scan demonstrating lesion in the occipital lobe of the brain and/or affecting white matter tracts that provide visual input to the occipital lobe of the brain
• Brain injury due to ischemic or hemorrhagic causes that occurs after age 18 and at least 90 days prior to screening visit
• At least two reliable HVF's demonstrating good fixation and a stable homonymous incomplete (e.g., quadrantanopia or relative defect) or complete hemianopia
• Reliable HVFs with repeat HVFs if randomization takes place more than 4 weeks after screening visit
• A homonymous, contiguous visual deficit measured by the 24-2 HVF to be a minimum of two testing locations high and two testing locations wide, where impaired locations are any that measure a threshold of less than 15 dB.
• Demonstration of good fixation on visual training task - able to fixate the small targets presented as fixation letters reliably for 1000ms with jitter over less than 1 degree of visual angle in any direction away from target edge

Exclusion criteria

• Physical, neurological or mental disability that would interfere with study intervention
• Concurrent participation in "vision therapy" other than standard occupational or physical therapy
• Unreliable visual fields on prior testing, indicated by greater than 20% fixation losses, false positives, or false negatives.
• Inability to discontinue medications judged to affect training and/or assessment (e.g., Ritalin, amphetamines, dopamines, or chemotherapeutic agents)
• Physical condition likely to preclude completion of the clinical trial (e.g. end-stage or uncontrolled cancer, uncontrolled epilepsy, or end-stage heart disease)
• Ocular or neurological condition that would interfere with training or assessment (e.g. damage to the optic nerves or lateral geniculate nucleus, any degenerative ocular condition)
• Best corrected vision worse than 20/40
• Impaired foveal Humphrey sensitivity as indicated by the HVF tests.
• Presence of vision loss resulting from ocular disease or disorder
• Presence of bilateral visual acuity loss from any source
• Inability to demonstrate fixation stability on eye movement monitored testing
• Inability to follow training instructions