Cylindrical power is a type of refractive error that occurs when the shape of the cornea, the frontmost layer of the eye, is more oblate rugby ball-like than spherical. This shape causes the power to be manifested only in a particular orientation called the axis. Cylindrical power is also known as astigmatism. It is not harmful, but it can cause symptoms such as headaches, eye strain, and fatigue. If left untreated, it can also lead to amblyopia, or “lazy eye” and diplopia (double vision). Cylindrical power can be corrected through various methods such as glasses, contact lenses, and refractive surgery. The most effective way to reduce cylindrical power is through refractive surgery such as LASIK or PRK. However, it is always best to consult with an ophthalmologist.