Anisometropia is a condition in which the lenses of the two eyes have different focal lengths; that is, are in different states of myopia (nearsightedness) and hyperopia (farsightedness).

Anisometropia is a concern in infants and young children, as the difference in prescription causes problems for the visual part of the brain. Eventually, the image from one of the eyes may be suppressed, a condition called amblyopia or lazy eye. If left untreated, the patient may become effectively blind in that eye despite its being physically healthy.

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