Understanding Homonymous quadrantanopia
Quadrantanopia refers to a quadrant-like region of field loss. Homonymous means a corresponding side of space is affected in both eyes, usually from a posterior visual-pathway lesion. Actual field maps can be incomplete, irregular or less tidy than a diagram. [1] [2]
Acuity at the center may remain useful while navigation, reading or noticing objects in the affected region becomes difficult. The field defect describes location and extent, not the underlying disease or a fixed degree of disability. [1] [2]
One condition. Different experiences.
Explore different selected symptom features, then read how they may vary. These examples are not stages or a clinical test.
Original VisualSim schematic illustrations, informed by the cited clinical descriptions. These are not study figures, patient recordings or validated severity levels.
Objects can be missed
An item in the affected field may go unnoticed even though it is clear when viewed in a different direction. [1] [2]
Reading or navigation
The impact depends on the field location, task, coexisting deficits and adaptation, not only the category name. [1] [2]
Awareness varies
A person may not perceive a literal black patch. The experience can be difficult to describe and may be confused with a problem in one eye. [2] [3]
A shared region of visual space
Original educational schematic; it does not diagnose, predict an individual outcome or reproduce a patient’s perception. [1] [2]
Original VisualSim teaching diagram · © VisualSim. Clinical basis in linked sources; not a published study figure. Image provenance.- Clinical pattern
Measure the affected region in each eye.
- Assessment
Localize the posterior pattern and investigate the cause.
- Support
Support the tasks affected by the actual field profile.
What is happening—and what remains uncertain
After the optic chiasm, each side of the brain processes the opposite side of visual space from both eyes. Partial lesions of these pathways can produce corresponding quadrant-like deficits. [2]
Field shape and associated neurological findings help clinical localization, but a diagram cannot identify one exact lesion or cause. Stroke, injury and other posterior pathology require their own assessment. [1] [2]
What can look similar?
Monocular loss
Loss confined to one eye has a different localization question from a homonymous pattern across both eyes. [2]
Hemianopia
A half-field pattern is related but larger in its descriptive extent; an individual perimetry map may not fit a perfect geometric division. [2]
Neglect
Biased spatial attention is different from sensory field loss, although the two can coexist and affect rehabilitation. [4]
Similar-looking symptoms can have different causes. A matching picture cannot establish a diagnosis.
What an assessment may involve
- Measure the field in each eyeFormal perimetry where feasible and clinical field assessment establish the distribution rather than a subjective black-shape drawing alone. [1] [2]
- Assess ocular and neurological contextAcuity, eye health and neurological examination help interpret the pattern and other contributors. [2]
- Investigate cause and functionImaging and appropriate medical evaluation assess posterior pathology, while rehabilitation examines reading, mobility and the actual daily tasks affected. [2] [4]
What may help—and what is still being studied
Treat the underlying cause
The field label does not specify whether an acute stroke pathway, another neurological treatment or stable follow-up is appropriate. [2]
What this can mean for daily life
Make important items easier to locate
Discuss consistent placement, visual cues and purposeful scanning strategies with rehabilitation staff. The best strategy depends on the measured field and associated attention. [3] [4]
Assess reading directly
Text layout, field location and eye movements can create different reading barriers; request task-specific assessment rather than assuming enlargement solves it. [3] [4]
Bring a clearer description to your appointment
Choose the questions you want to discuss. These choices stay in this page’s memory.
Research, with the context left in
Selected studies and guidance, with their populations and limitations. These are curated educational summaries, not a complete systematic review or a formal evidence rating.
Visual Loss Due to Optic Chiasm and Retrochiasmal Visual Pathway Lesions
Explains corresponding field patterns and posterior-pathway interpretation. [2]
Limits and applicability: Localization patterns are not exact lesion diagnoses or personal prognosis estimates.
European Stroke Organisation guideline on visual impairment in stroke
Supports structured detection, specialist assessment and individualized rehabilitation across stroke visual impairments. [4]
Limits and applicability: Stroke evidence and recommendations differ by visual domain and cannot be assumed to prove field restoration.
SEARCH visual scanning training trial
Found no between-group advantage on the primary outcome at the specified follow-up. [5]
Limits and applicability: Participants had hemianopia; the finding is indirect for quadrantanopia and does not refute every individualized access strategy. Attrition and adherence also affect interpretation.
Questions researchers still need to answer
- Which compensatory strategies improve real-world outcomes specifically in quadrant defects?
- How do field location and coexisting attention problems modify rehabilitation benefit?
Trusted places to go next
Selected clinical references, research, practical support and ways to connect. Official pages checked 24 October 2026; each entry explains its scope and region.
Cleveland Clinic — Quadrantanopia
Condition-specific information to discuss with the treating team.
NANOS — Homonymous field loss
Explains the same-side-in-both-eyes principle; broader half-field context is distinguished from quadrant loss.
RNIB — Vision after stroke
Field and other stroke-vision support information.
Headway — Acquired brain injury support
Broader daily-life and rehabilitation support when acquired brain injury is the cause.
Connections listed by the organization.
Questions you may still have
Is this just losing a quarter of one eye?
A homonymous pattern affects corresponding visual space in both eyes; individual fields need measurement. [1] [2]
Will closing one eye fix it?
Not a true homonymous field defect, because the corresponding region is affected through both eyes. [2] [3]
Sources, image credits and review status
Compiled by VisualSim from clinical references and published research. Sources checked 24 October 2026. Independent clinical review has not been recorded; no named clinical reviewer or clinical validation is claimed. Research evidence and its limitations are linked below.
- Cleveland Clinic — Quadrantanopia (2023; institution).
Official clinical source checked for this topic; source checking is not clinical review.
Checked 2026-10-24 · Public page checked - Glisson — Visual Loss Due to Optic Chiasm and Retrochiasmal Visual Pathway Lesions (2014; review).
Official clinical source checked for this topic; source checking is not clinical review.
Checked 2026-10-24 · Abstract/indexed material checked; complete full-text review not claimed - NANOS — Homonymous hemianopia (n.d.; institution).
Official clinical source checked for this topic; source checking is not clinical review.
Checked 2026-10-24 · Public page checked - ESO guideline on visual impairment in stroke (2025; guideline).
Europe PMC XML read in the coverage audit; certainty and recommendation strength are outcome-specific.
Checked 2026-10-24 · Full text checked - SEARCH visual scanning training trial (2025; trial).
Official trial abstract checked; no primary between-group benefit and indirect quadrantanopia applicability retained.
Checked 2026-10-24 · Abstract/indexed material checked; complete full-text review not claimed - RNIB — Stroke-related eye conditions (n.d.; institution).
Official clinical source checked for this topic; source checking is not clinical review.
Checked 2026-10-24 · Public page checked
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