<unk>  may be a result of optical magnification differences between the eyes, retinal receptor distribution, or the cortical processing of the sampled image. The current hypothesis for the occurrence of dysmetropsia is due to the stretching or compression of the retina leading to the displacement of receptors.<unk>  arises from a compressed receptor distribution leading to a larger perceived image size and conversely,<unk>  results from stretching of the retina leading to a more sparse receptor distribution that gives a smaller perceived image size. In the case of<unk> , the greater density of photoreceptor cells leads to greater stimulation making the object seem larger. In some cases, the effects of<unk>  have been shown to be field dependent, in that the degree of visual distortion is related to the visual field angle. Non-uniform stretching or compression of the receptor distribution could explain the field dependency of the<unk> . If the compression forces were closer to the fovea the resulting compression would cause a greater amount of<unk>  at lower field angles with little effect at higher field angles where the receptor distribution is not as compressed. Alterations in receptor distribution can be the result of epiretinal membrane, neuroretina detachment and/or re-attachment, or retinoschisis.<unk>  caused by surgical re-attachment of macula-off rhegmatogenous retinal detachment is not symmetrical around the fovea, resulting in differences size changes in the horizontal and vertical meridians. Asymmetry has also been observed with retinoschisis, in which<unk>  generally results in the vertical direction while<unk>  presents in the horizontal direction.
Macropsia
Cerebral polyopia
Ocular dysmetria
Tunnel vision
Cyanopsia
Quadrantanopia
Photopsia
Optic disc pallor