With metamorphopsia (perceptual distortion), the patient reports that linear objects appear curved or discontinuous. This symptom is characteristic of macular disease and may occur with epiretinal, intraretinal, or subretinal pathology (eg, proliferative vitreoretinopathy, cystoid macular edema, retinal pigment epithelial detachments, subretinal neovascular membranes, or choroidal circulatory problems).
With intraretinal edema, the retinal elements are often pushed apart, causing perceived image shrinkage (micropsia). Macropsia (perceived image enlargement) can occur if the photoreceptors are pushed together.
The retina may be the source of changes in color perception associated with drug effects (eg, digoxin-induced yellowing of vision, sildenafil citrate (Viagra)-induced blue tinge). Other changes of color perception may be related to choroidal or retinal ischemia (eg, giant cell arteritis), which can also lead to persistent afterimages.