Image Magnification (Macropsia)

What macropsia is like

People describe:

• text or faces looking larger in one eye when the other is covered
• a mismatch between the two eyes that makes reading or judging distance tiring
• episodes in which their hands, the room or people suddenly seem huge or far too close
• straight lines also looking wavy, if the retina is distorted

The opposite, objects looking smaller, is called micropsia. Both are types of dysmetropsia and can occur together. Doctors also distinguish macropsia from distorted vision in general, though the two often occur together.

Causes in one eye: the retina and optics

Epiretinal membrane

A thin layer of scar tissue on the macula contracts and draws the cone cells closer together. More cones are stimulated by the same image, so the brain reads it as larger. Macropsia with wavy lines is typical. See epiretinal membrane.

Macular swelling and fluid

Macular edema from diabetes, retinal vein occlusion or after eye surgery can change the spacing of cells and alter image size. Fluid under the retina, as in central serous chorioretinopathy, more often makes objects look smaller, but size changes in either direction occur.

Glasses, contact lenses and surgery

• New or stronger glasses for farsightedness (plus lenses) enlarge images slightly. Most people adapt within 1 to 2 weeks.
• Aniseikonia: when the two eyes need very different prescriptions, or after cataract or retinal surgery in one eye, the image size can differ between eyes, causing strain, headaches and double vision.
• After retinal detachment repair or macular hole surgery, image size can be altered for months.

Causes in both eyes: the brain

Migraine and Alice in Wonderland syndrome

Alice in Wonderland syndrome is a set of brief perceptual changes in which body parts or objects seem to change size, shape or distance, and time may seem to speed up or slow down. It is most often linked with migraine, particularly in children, and may occur with or without headache. Episodes typically last minutes. It is usually harmless and often fades with age.

Infections

In children, Alice in Wonderland symptoms can appear with Epstein-Barr virus infection (mononucleosis) and other viral infections, then settle as the infection clears.

Seizures

Focal seizures arising in the temporal or occipital lobes can cause brief episodes of objects growing or shrinking, often with déjà vu, odd smells or tastes, or a rising feeling in the stomach. See epilepsy.

Other causes

• Stroke or other lesions affecting the visual pathways (rare, usually with other symptoms)
• Hallucinogenic drugs, cannabis and some medicines
• Very high fever, especially in children
• Sleep deprivation and drifting off to sleep, when brief size distortions can occur

How to tell eye causes from brain causes

How macropsia is diagnosed

An optometrist or ophthalmologist checks vision and glasses in each eye, uses an Amsler grid, and examines the retina. An OCT scan shows membranes, swelling and fluid. Special charts can measure size differences between the eyes. If both eyes are affected or there are episodes, a doctor may arrange a neurological assessment, an EEG for possible seizures, or brain imaging.

Treatment

• Lens-related causes: adjusting the prescription, switching to contact lenses, or special size-correcting lenses for aniseikonia.
• Epiretinal membrane: observation if mild; surgery (vitrectomy with membrane peel) if vision is significantly affected. Distortion usually improves but may not disappear completely.
• Macular edema: treating diabetes or vein occlusion, injections into the eye or laser.
• Migraine and Alice in Wonderland syndrome: reassurance, identifying triggers such as sleep loss and stress, and migraine treatment or prevention if attacks are frequent.
• Seizures: anti-seizure medicine.

Frequently asked questions

Why do things look bigger in one eye?

Usually because of a retinal problem such as an epiretinal membrane or macular swelling, or because the two eyes have different prescriptions or one has had surgery. Covering each eye in turn helps confirm it. An eye doctor can find the cause with an exam and OCT scan.

What is Alice in Wonderland syndrome?

It is a condition in which objects, people or your own body briefly seem too big, too small, too near or too far, and time may feel distorted. It is most common in children and is usually linked to migraine or viral infections such as mononucleosis. It is generally harmless.

Can new glasses make things look bigger?

Yes. Glasses for farsightedness slightly magnify images, and a big change in prescription can make things look larger or the floor seem closer. Most people adapt within one to two weeks. If not, have the prescription and fitting checked.

Is macropsia serious?

Usually not, but it is a symptom that needs explaining. New macropsia in one eye may reflect a retinal problem that benefits from treatment. Episodes with weakness, speech problems or seizures need urgent assessment.