What is the major cause of vertical imbalance?

Vertical imbalance refers to a phenomenon where there is a difference in the amount of vertical prism effect between the two eyes, leading to misalignment that can cause visual discomfort or double vision. Anisometropia is the major cause of vertical imbalance because it involves a significant difference in the refractive power of each eye. When one eye requires a different lens prescription than the other, it can result in unequal amounts of vertical prismatic effect, particularly if the prescribed lenses are incorrectly compensated for the differences in refractive error.

For instance, if one eye needs significantly more plus or minus power compared to the other, it can cause vertical misalignment, leading to the symptoms associated with vertical imbalance. This condition specifically and directly affects how images are perceived vertically, making it the primary concern when diagnosing and treating vertical imbalance in patients.

Presbyopia, astigmatism, and hyperopia all relate to different aspects of vision correction and may contribute to visual disturbances, but they are not directly associated with the specific issue of vertical imbalance as anisometropia is. In essence, anisometropia stands out as the central factor in creating discrepancies in visual alignment between the two eyes, thus leading to vertical imbalance.