Retinal image size is determined by many factors. The size and position of the object being viewed affects the characteristics of the light entering the system. Corrective lenses affect these characteristics and are used commonly to correct refractive error. The optics of the eye including its refractive power and axial length also play a major role in retinal image size.<unk>  can occur naturally or be induced by the correction of a refractive error, usually anisometropia (having significantly different refractive errors between each eye) or antimetropia (being myopic (nearsighted) in one eye and hyperopic (farsighted) in the other.) Meridional<unk>  occurs when these refractive differences only occur in one meridian (see astigmatism). One cause of significant anisometropia and subsequent<unk>  has been aphakia. Aphakic patients do not have a crystalline lens. The crystalline lens is often removed because of opacities called cataracts. The absence of this lens left the patient highly hyperopic (farsighted) in that eye. For some patients the removal was only performed on one eye, resulting in the anisometropia /<unk> . Today, this is rarely a problem because when the lens is removed in cataract surgery, an intraocular lens, or IOL is left in its place. Retinal<unk>  occur due to forward displacement, stretching or edema of retina.
Aniseikonia
Coprolalia
Synkinesis
Hypermastigia
Echolalia
Acrodynia
Hyperekplexia
Choreoathetosis