Keratoconus (KC) is a bilateral progressive disease that often begins in young adulthood. Advanced KC significantly impairs patients’ quality of life, making early detection of the condition a critical goal for specialists. Early identification of KC greatly influences both the treatment strategy and the outcomes. This review focuses on the ocular wavefront in KC, which is of interest from the perspective of early diagnosis. The article outlines the nature of optical aberrations in the eye, particularly in KC, and the principles of wavefront aberration analysis. An increase in higher-order aberrations is one of the earliest signs of incipient KC and a key contributor to reduced visual quality. Some of the widely used KC treatment methods, such as corneal cross-linking and the implantation of intracorneal segments, has been established to positively impact many aspects of KC pathogenesis, including reduction in higher-order aberrations, which in turn improves visual quality. Monitoring of the outcomes of treatment or optical correction in KC using higher-order aberrations is a delicate approach, as vision improvements following treatment are often unexplained by routine eye examination methods. However, the choice of the optimal method of visual rehabilitation for KC patients remains unresolved. Efforts to find new treatment methods, primarily through combinations and modifications of existing techniques, are ongoing. The article discusses this promising approach of using wavefront as an additional criterion for assessing the performance of the optical system in the diagnosis, treatment, and optical correction of KC.