WATCH: Dr. Andrew Lee Shares 5 Key Visual Field Rules for Spotting a Brain Tumor

In a new whiteboard video released by Houston Methodist Hospital, Dr. Andrew G. Lee, chair of the Blanton Eye Institute and a leading neuro-ophthalmologist, breaks down the five essential visual field rules that can help clinicians avoid missing a brain tumor during patient evaluations.

In the video, Dr. Lee walks viewers through the anatomy of the visual pathway and explains how certain patterns of vision loss can be key indicators of underlying lesions in the brain.

"The most important rule is to respect the vertical meridian in the visual field," Dr. Lee emphasized. "Any visual field defect that respects the vertical midline is a red flag for a compressive brain tumor and should prompt immediate imaging."

Using hand-drawn illustrations and helpful terminology, Dr. Lee guides clinicians through the pathway from the eye to the occipital cortex, highlighting how disruptions along this path — from the optic nerve and chiasm to the geniculate body and radiations — produce distinct visual field patterns.

According to Dr. Lee, the most clinically relevant signs include:

• Junctional Scotoma of Traquair – a one-eye field defect at the junction of the optic nerve and chiasm that respects the vertical meridian
• Bitemporal Hemianopsia – a hallmark of chiasmal compression, most often due to a suprasellar mass like a pituitary tumor
• Homonymous Hemianopsia with RAPD and Atrophy – indicative of a lesion in the optic tract
• "Pac-Man" or Hourglass Defects – visual field clues pointing to damage at the lateral geniculate body
• Pie in the Sky / Pie on the Floor – superior or inferior quadrant loss linked to temporal or parietal lobe involvement, respectively

Dr. Lee also explains macular sparing in occipital lobe lesions, due to the dual blood supply from the middle and posterior cerebral arteries, a nuance that can help localize cortical strokes.

The video is part of Houston Methodist's ongoing whiteboard learning series, aimed at providing easily digestible, clinically actionable insights for frontline medical professionals.