Visual Field Defect Patterns Associated With Lesions of the Retrochiasmal Visual Pathway

Area of Science:

• Neuroscience
• Ophthalmology
• Radiology

Background:

• Perimetry is crucial for localizing retrochiasmal visual pathway lesions.
• Traditional interpretations of visual field defects (macular sparing, homonymous paracentral scotomas, quadrantanopias, incongruous hemianopia) are being re-evaluated for specificity.
• Previous studies have questioned the definitive localization power of these patterns.

Purpose of the Study:

• To correlate specific magnetic resonance imaging (MRI)-defined retrochiasmal visual pathway lesions with visual field defect patterns.
• To assess the diagnostic accuracy of perimetry in localizing lesions within distinct segments of the retrochiasmal visual pathway.
• To clarify the association between incongruous hemianopias and anterior retrochiasmal lesions.

Main Methods:

• Retrospective review of patient records from an academic medical center.
• Inclusion criteria: reliable visual fields, high-quality MRI scans, and pertinent retrochiasmal lesions.
• MRI lesions were segmented by a neuroradiologist; visual fields were analyzed for 10 defect patterns by two independent reviewers.

Main Results:

• Of 83 included cases, specific lesion-defect correlations were analyzed.
• Macular sparing, homonymous paracentral scotomas, and quadrantanopias were associated with visual cortex and posterior optic radiations but not exclusively.
• Incongruous hemianopias predominantly resulted from optic tract lesions, though this pattern was uncommon.

Conclusions:

• The study refines the understanding of visual field defect patterns in localizing retrochiasmal lesions.
• Macular sparing, homonymous paracentral scotomas, and quadrantanopias are not exclusively indicative of posterior pathway lesions.
• Incongruous hemianopias are more strongly associated with optic tract lesions than previously suggested.