What is 'isometropia' characterized by?

Isometropia is characterized by the condition in which both eyes have the same refractive power and sign, meaning that if one eye is, for example, +2.00 diopters, the other eye is also +2.00 diopters, or if one eye is -2.00 diopters, the other eye is also -2.00 diopters. This uniformity in refractive error indicates that both eyes can focus light similarly, which typically results in better coordination and visual comfort.

In contrast, differences in refractive power or signs, as indicated in the other options, lead to conditions such as anisometropia where the eyes do not have equal refractive power. General vision impairment can occur due to various conditions beyond just refractive differences and is not a defining characteristic of isometropia. Understanding these distinctions is vital for opticians in diagnosing and treating patients effectively.