Visual discrimination training improves Humphrey perimetry in chronic cortically induced blindness

Area of Science:

• Neuroscience
• Ophthalmology
• Rehabilitation Medicine

Background:

• Chronic stroke can lead to cortical visual impairment due to damage in the visual cortex.
• Cortical blindness significantly impacts daily functioning and quality of life.
• Current vision restoration strategies for cortical visual impairment are limited.

Purpose of the Study:

• To evaluate the efficacy of visual discrimination training in improving visual field performance in chronic stroke patients.
• To determine if targeted training can enhance visual function in areas affected by cortical blindness.

Main Methods:

• Seventeen chronic stroke patients with cortical blindness underwent visual discrimination training (direction, orientation, or both) in their blind visual field.
• Humphrey visual fields (24-2 and 10-2) were assessed before and after training.
• Gaze-contingent eye tracking ensured accurate stimulus presentation during training and testing.

Main Results:

• Trained patients demonstrated an average visual field recovery of approximately 108 degrees squared.
• Untrained control patients showed minimal spontaneous improvement (around 16 degrees squared) with some areas of worsening.
• Visual field gains were proportional to the amount of training and extended beyond trained locations, particularly along the blind field border.

Conclusions:

• Gaze-controlled visual discrimination training can effectively leverage the plastic potential at the blind field border to expand the visual field in adults with chronic cortical visual impairment.
• This approach offers a promising avenue for vision restoration in stroke survivors.
• Further research with larger cohorts is warranted to validate these findings and explore broader applications.