Quadrantanopia is the loss of vision in one quarter of your visual field. Unlike hemianopia, which affects an entire half of what you see, quadrantanopia is limited to a single quadrant, either upper or lower, on one side. It results from damage to the brain’s visual processing pathways rather than a problem with the eyes themselves, and it typically affects the same quadrant in both eyes.
How the Visual Field Is Divided
Your full visual field can be split into four quadrants: upper left, upper right, lower left, and lower right. In quadrantanopia, one of these quadrants goes dark or becomes severely impaired. The word “homonymous” is often attached to the diagnosis, meaning the same-side quadrant is missing in both eyes. So if you have a right upper quadrantanopia, you’re missing the upper-right portion of vision in your left eye and your right eye simultaneously.
There are two main types:
- Superior quadrantanopia affects the upper quadrant on one side. It’s sometimes called “pie in the sky” because the missing area is above your line of sight.
- Inferior quadrantanopia affects the lower quadrant on one side, sometimes called “pie on the floor.”
Why It Happens: Brain Pathways, Not Eye Problems
Visual information travels from the eyes to the back of the brain through a bundle of nerve fibers called the optic radiation. This bundle splits into two routes. One set of fibers loops forward through the temporal lobe before curving back toward the visual cortex. This loop, called Meyer’s loop, carries information about what you see in the upper visual field. A second set of fibers travels through the parietal lobe and carries information about the lower visual field.
Damage to Meyer’s loop in the temporal lobe causes superior quadrantanopia, the “pie in the sky” pattern, because the fibers responsible for upper-field vision are disrupted. Damage to the parietal lobe pathway causes inferior quadrantanopia, since those fibers handle the lower field. The visual cortex at the very back of the brain is also divided: the lower portion processes upper-field vision and the upper portion handles lower-field vision. A lesion in either section of the cortex produces the corresponding quadrant loss.
Common Causes
Stroke is the most frequent cause. When blood supply to the temporal lobe, parietal lobe, or occipital lobe is interrupted, the resulting damage can knock out one of those fiber pathways or a section of the visual cortex. Tumors growing in or pressing on these regions can produce the same effect, as can traumatic brain injuries.
Brain surgery is another well-documented cause, particularly temporal lobe resections performed to treat epilepsy. In one study, 76% of patients who underwent anterior temporal lobe resection showed an upper-quadrant visual field deficit afterward, because the surgery unavoidably passes near Meyer’s loop. This complication can affect driving eligibility in roughly one in five of those patients.
What It Feels Like
Many people with quadrantanopia don’t immediately realize a quadrant is missing. The brain is good at filling in gaps, so the experience isn’t like seeing a black box in the corner of your vision. Instead, you might notice that you bump into objects on one side, miss words at the edge of a page, or feel uneasy in busy environments without understanding why. Driving can feel uncomfortable because cars or pedestrians seem to “appear out of nowhere” from the affected side.
An interesting phenomenon called statokinetic dissociation can occur: some people with quadrantanopia can perceive moving objects in the blind quadrant but completely miss stationary ones. On a formal vision test using still dots of light, the quadrant appears empty, yet the person may detect a hand waving in that same area.
How It’s Diagnosed
The standard diagnostic tool is automated perimetry, most commonly the Humphrey Visual Field test. You sit in front of a bowl-shaped screen, fix your gaze on a central point, and press a button each time you notice a small flash of light. The machine maps where you can and cannot see, producing a printout that clearly outlines which quadrant is affected. Patterns like the 24-2 or 30-2 are typically used to evaluate the central 24 or 30 degrees of vision on each side.
Goldmann perimetry, an older manual technique where a technician moves a light target along an arc, is still used in some settings. It’s particularly useful for mapping the outer boundaries of the visual field and for detecting cases of statokinetic dissociation, where moving targets are seen but static ones are not.
Once a quadrantanopia is confirmed on a visual field test, brain imaging (usually an MRI) follows to identify the underlying cause, whether it’s a stroke, tumor, or other lesion along the visual pathway.
Quadrantanopia vs. Hemianopia
Hemianopia means half the visual field is gone on one side. Quadrantanopia means only one quarter is gone. In practical terms, quadrantanopia is a less extensive deficit, but it can still significantly affect daily life, particularly driving, reading, and navigating crowded spaces. Some quadrantanopias gradually expand into a full hemianopia if the underlying brain damage progresses, which is why follow-up visual field testing matters.
Recovery and Outlook
Some degree of spontaneous visual field recovery does occur, but it’s unpredictable. Studies report recovery in anywhere from 7% to 85% of cases, a wide range that reflects differences in how recovery is measured and how severe the initial damage was. The window for natural improvement is relatively short. Most spontaneous recovery happens within the first three months after the brain injury, and the rate of improvement drops off sharply after that. Complete recovery is rare.
Rehabilitation Strategies
Because spontaneous recovery is limited, rehabilitation focuses on teaching you to compensate for the blind quadrant rather than restoring lost vision directly.
Visual scanning training is the most widely used approach. You practice making deliberate, repeated eye movements into the blind area so that scanning toward the affected side becomes automatic. Over multiple sessions, this can meaningfully improve your ability to spot objects, read across a full page, and move safely through your environment.
Prism glasses are another option. These use special lenses that shift images from the blind quadrant into the intact portion of your visual field. When wearing prismatic lenses with a deviation of around 10 degrees, many people learn to use the shifted image as a cue to turn their head and look into the affected area. The adjustment takes practice, typically across 10 to 20 sessions, and stronger prism prescriptions tend to produce better results than weaker ones.
Neither approach “cures” the field loss, but both can reduce the functional impact. Many people who don’t receive any rehabilitation never develop effective compensatory habits on their own, so working with a vision rehabilitation specialist or neuro-optometrist is generally worthwhile, especially in the first few months after diagnosis when the brain is most adaptable.