Anisometropia is the condition in which the two eyes have unequal refractive power; that is, are in different states of myopia (nearsightedness) or hyperopia (farsightedness), the unequal refractive states cause unequal rotations thus leading to diplopia and astenopia.

Anisometropia can adversely affect the development of binocular vision in infants and children if there is a large difference in clarity between the two eyes. The brain will often suppress the vision of the blurrier eye in a condition called amblyopia, or lazy eye.

For those with large degress of anisometropia, spectacle correction may cause the person to experience a difference in image magnification between the two eyes which could also prevent the development of good binocular vision.

The name is from four Greek components: an- "not," iso- "same," metr- "measure," ops "eye."

Ophthalmology