<unk>  is when two eyes have unequal refractive power. Generally, a difference in power of two diopters or more is the accepted threshold to label the condition<unk> . In certain types of<unk> , the visual cortex of the brain will not process images from both eyes together (binocular summation), and will instead suppress the central vision of one of the eyes. If this occurs often enough during the first 10 years of life while the visual cortex is developing, it can result in amblyopia, a condition where even when correcting the refractive error properly, the person's vision in the affected eye is still not correctable to 20/20. The name is from four Greek components: an- "not," iso- "same," metr- "measure," ops "eye." Antimetropia is a rare sub-type of<unk> , in which one eye is myopic (nearsighted) and the other eye is hyperopic (farsighted). Around 0.1% of the population may be antimetropic.
Anisometropia
Hypertropia
Emmetropia
Cyclotropia
Physiological anisocoria
Exotropia
Ocular dysmetria
Heterotopia 