Visual field expansion after visual restoration therapy

Area of Science:

• Neuroscience
• Ophthalmology
• Rehabilitation Medicine

Background:

• Stroke-induced homonymous field cuts significantly impair vision and quality of life.
• Visual restoration therapy (VRT) is a home-based computerized treatment designed to address these visual field defects.
• The efficacy of VRT, particularly regarding true visual field expansion versus artifact, remains a subject of investigation.

Purpose of the Study:

• To objectively assess visual field expansion following Visual Restoration Therapy (VRT).
• To differentiate true visual field gains from potential artifacts caused by eye movements.

Main Methods:

• A longitudinal cohort study involving seven patients with stroke-induced homonymous field cuts.
• Visual fields were assessed before and after a three-month VRT intervention using both standard high-resolution perimetry and fundus-controlled microperimetry.
• Fundus-controlled microperimetry was employed to ensure accurate stimulus delivery to known retinal locations, independent of eye movements.

Main Results:

• An average improvement of 12.5% in stimulus detection rate was observed using microperimetry (P=0.033).
• Six out of seven patients demonstrated a clinically significant improvement (≥3%) in stimulus detection.
• These improvements were validated by fundus-controlled microperimetry, mitigating concerns about eye movement artifacts.

Conclusions:

• Visual restoration therapy leads to a modest but genuine expansion of visual fields in patients with homonymous hemianopia.
• The observed visual field gains are not a result of compensatory eye movements, confirming the therapeutic effect of VRT.
• Fundus-controlled microperimetry is a crucial tool for accurately evaluating visual field changes in VRT studies.