Anisometropia is a condition where there is a significant difference in the refractive errors of the two eyes.

If this condition is present in infancy and is undetected or untreated, it often results in the development of lazy eye or amblyopia in the more hyperopic (far-sighted) eye. The greater the amount of the difference, the more likely the development of lazy eye will be.

Another problem can occur when glasses are made for an anisometropic individual. The difference in the powers of the lenses induce a prismatic difference that can cause double vision in off-center areas of the lens, which can be compensated for by the use of slab-off prism.