Whatever the cause, the bodily related distortions can recur several times a day and may take some time to abate. Understandably, the person can become alarmed, frightened, and panic-stricken throughout the course of the hallucinations—maybe even hurt themselves or others around them. The symptoms of the syndrome themselves are not harmful and are likely to disappear with time.

Alice in Wonderland syndrome is a disturbance of perception rather than a specific physiological change to the body's systems. The diagnosis can be presumed when other causes have been ruled out and if the patient presents symptoms along with migraines and complains of onset during the day (although it can also occur at night).

Another symptom of Alice in Wonderland syndrome is sound distortion, such as every little movement making a clattering sound.

Macropsia is generally diagnosed once a patient complains of the characteristic symptoms, such as disproportionally large objects in their visual field. The Amsler Grid test can be used to diagnose macropsia, along with other visual maladies depending on the subjective disturbance reported by the patient after looking at the Amsler Grid. Outward bulging of the lines on an Amsler Grid is consistent with patients experiencing macropsisa. The New Aniseikonia Test (NAT) can quantify the degree of macropsia or micropsia independently in the vertical and horizontal meridians. The test consists of red and green semicircles on a black background with a white round fixation target. The size of the red semicircle is held constant while the green semicircle is varied in size in 1% increments. The patient wears a pair of red/green goggles so that one eye is tested at a time, and the patient attempts to determine when the semicircles are the same size. This is termed the reversal threshold and the size difference between the semicircles is reported as the degree of aniseikonia. A positive value indicates that the object was perceived bigger and thus corresponds to macropsia, and conversely a negative value indicates micropsia. The Aniseikonia Inspector contains an aniseikonia test based on the same principles as the NAT, but the test is run on a computer screen, it is based on a forced choice method, and it can measure the size difference as a function of the size of the objects. The functionality of being able to measure the size difference as function of the size (i.e. field dependent testing) is especially important when the macropsia (or micropsia) has a retinal origin.

The most common way to treat forms of aniseikonia, including macropsia, is through the use of auxiliary optics to correct for the magnification properties of the eyes. This method includes changing the shape of spectacle lenses, changing the vertex distances with contact lenses, creating a weak telescope system with contact lenses and spectacles, and changing the power of one of the spectacle lenses. Computer software, such as the Aniseikonia Inspector, has been developed to determine the prescription needed to correct for a certain degree of aniseikonia. The problem with correction through optical means is that the optics do not vary with field angle and thus cannot compensate for non-uniform macropsia. Patients have reported significantly improved visual comfort associated with a correction of 5-10% of the aniseikonia.

With regard to drug-induced or virus-induced macropsia, once the underlying problem, either drug abuse or viral infection, is treated, the induced macropsia ceases.