It can also be difficult for some people with CVI to look at an object and reach for it at the same time. Looking and reaching are sometimes accomplished as two separate acts: look, then look away and reach. People with CVI can sometimes benefit from a form of blindsight, which manifests itself as a kind of awareness of ones surroundings that cannot consciously be explained (for example, the person correctly guesses what they should do in order to avoid an obstacle but does not actually see that obstacle). However, this cannot be relied on to work all the time. In contrast, some people with CVI exhibit spatial difficulties and may have trouble moving about in their environment. Approximately one third of people with CVI have some photophobia. It can take longer than usual to adjust to large changes in light level, and flash photography can be painful. On the other hand, CVI can also in some cases cause a desire to gaze compulsively at light sources, including such things as candle flames and fluorescent overhead lights. The use of good task lighting (especially low-temperature lamps which can be placed at very close range) is often beneficial. Although people (with or without CVI) generally assume that they see things as they really are, in reality the brain may be doing a certain amount of guessing and "filling in", which is why people sometimes think they see things that turn out on closer inspection not to be what they seemed.
Micropsia is a condition affecting human visual perception in which objects are perceived to be smaller than they actually are. Micropsia can be caused by optical factors (such as wearing glasses), by distortion of images in the eye (such as optically, via swelling of the cornea or from changes in the shape of the retina such as from retinal edema, macular degeneration, or central serous retinopathy), by changes in the brain (such as from traumatic brain injury, epilepsy, migraines, prescription drugs, and illicit drugs), and from psychological factors. Dissociative phenomena are linked with micropsia, which may be the result of brain-lateralization disturbance.Micropsia is also commonly reported when the eyes are fixating at (convergence), or focusing at (accommodation), a distance closer than that of the object in accord with Emmerts law. Specific types of micropsia include hemimicropsia, a form of micropsia that is localized to one half of the visual field and can be caused by brain lesions in one of the cerebral hemispheres. Related visual distortion conditions include macropsia, a less common condition with the reverse effect, and Alice in Wonderland syndrome, a condition that has symptoms that can include both micropsia and macropsia. Signs and symptoms
Micropsia causes affected individuals to perceive objects as being smaller or more distant than they actually are.The majority of individuals with micropsia are aware that their perceptions do not mimic reality. Many can imagine the actual sizes of objects and distances between objects.